TECHNOLOGICAL INSTITUTE OF PHILIPPINES

College of Engineering and Architecture

1338 Arlegui Street, Quiapo, Manila

In Partial Fulfillment of the Requirements for the

Subject

Electrical Standards and Practices

EE400 – EE41S1– S. Y. 2022-2023

“MOTORS: OPERATIONS AND MAINTENANCE AND

BEST PRACTICES”

Submitted to:

Engr. ARTURO M. ZABALA, PEE

Faculty-In-Charge (EE 400/EE41S1)

Submitted by:

Mr. Alfoque, Marvin Jay

Mr. Cinco, Khail Jann Glenn
Mr. Gaspar, Kriztan Mark B.
Mr. Portilla, Leonel

17 September 2022
 Motors: Operations and Maintenance and Best Practices

Honor Pledge for Group Projects

“I accept responsibility for my role in ensuring the integrity of the work submitted by the group in
which I participated.”

Title of the Report: Motors

Group No.: 9

Member: Alfoque, Marvin Jay

Member: Cinco, Khail Jann Glenn

Member: Gaspar, Kriztan Mark B.

Member:
Portilla, Leonel

Table of Contents
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 Motors: Operations and Maintenance and Best Practices

I. Introduction……………………………………………………………………………………4
I.1 Working Principles………………………………………………………………………...4
I.2 Magnetic Field……………………………………………………………………………..5
I.3 Electromagnetism………………………………………………………………………….5
I.4 Types of Motors…………………………………………………………………………...6
I.4.1 DC Motor……………………………………………………………………...6
a. Brushed DC motor…………………………………………………….7
b. Brushless DC motor…………………………………………………...7
I.4.2 AC Motor……………………………………………………………………...8
a. Induction motor…………………………………………………
b. Synchronous motor…………………………………………………
I.5 Key Components…………………………………………………………………
I.5.1 DC Motor……………………………………………………………………
a. Pole…………………………………………………………
b. Armature……………………………………………………………
c. Commutator…………………………………………………………
I.5.2 AC Motor……………………………………………………………………
a. Rotor………………………………………………………………
b. Stator…………………………………………………………………
I.6 Safety Issues…………………………………………………………………………….
I.7 Cost and Energy Efficiency……………………………………………………………..
I.8 Maintenance of Motors…………………………………………………………………
I.9 Diagnostic Equipment…………………………………………………………………
I.9.1 Thermography……………………………………………………………
I.9.2 Ultrasonic Analyzer…………………………………………………………..
I.9.3 Vibration Analyzer……………………………………………………………
I.10 Available Software Tools…………………………………………………………….
I.10.1 MotorMaster+………………………………………………………………
I.11 Relevant Operational Energy Efficient Measures……………………………………
I.11.1 Replace standard motors with energy efficient motors………………….
I.11.2 Sizing to variable load…………………………………………………………
I.11.3 Improving power quality……………………………………………………
I.11.4 Improving maintenance……………………………………………………….
I.11.5 A checklist of good……………………………………………………
I.11.6 Multi-speed motors……………………………………………………………
I.11.7 Variable speed drives (VSDs)………………………………………………
I.12 Electric Motors Checklist………………………………………………………
I.13 Energy Audit…………………………………………………………………………
I.13.1 What is a Motor Energy Audit?...............................................................
I.13.2 Relevant Tools…………………………………………………………………
I.13.3 Energy audit planning…………………………………………………..
I.13.4 Opening meeting & Data collection………………………………………..
I.13.5 Measurement plan………………………………………………………..
I.13.6 Data-Analysis………………………………………………………..
I.13.7 Energy Audit reporting………………………………………………..
I.13.8 Closing meeting…………………………………………………………..
II. Abbreviation…………………………………………………………………………………….
III. Definition of Terms…………………………………………………………………………
IV. Report Content…………………………………………………………………………………
V. Reference…………………………………………………………………………………

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 Motors: Operations and Maintenance and Best Practices

I. Introduction
Motor is an electrical machine that converts electrical energy into mechanical energy. Most
electric motors operate through the interaction between the motor's magnetic field and electric
current in a wire winding to generate force in the form of torque applied on the motor's shaft.
An electric generator is mechanically identical to an electric motor, but operates with a reversed
flow of power, converting mechanical energy into electrical energy. Motor systems consume
about 70% of all the electric energy used in the manufacturing sector of the United States. To
date, most public and private programs to improve motor system energy efficiency have focused
on the motor component. This is primarily due to the complexity associated with motor-driven
equipment and the system as a whole.

The electric motor itself, however, is only the core component of a much broader system of
electrical and mechanical equipment that provides a service. Numerous studies have shown that
opportunities for efficiency improvement and performance optimization are actually much
greater in the other components of the system-the controller, the mechanical system coupling,
the driven equipment, and the interaction with the process operation. Despite these significant
system-level opportunities, most efficiency improvement activities or programs have focused on
the motor component or other individual components.

Introduction to Electric Motors

Figure 1 Different Parts of Electric Motors

I.1 Working Principles of Motor

The working principle of a motor is based on the current-carrying conductor that

experiences a force when it is kept in the magnetic field. The working principle of the
generator is based on and operates using principles of electromagnetism, which shows
that a force is applied when an electric current is present in a magnetic field. This
force creates a torque on a loop of wire present in the magnetic field, which causes the
motor to spin and perform useful work.

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 Motors: Operations and Maintenance and Best Practices

I.2 Magnetic Field

Magnetic field is a vector field in the neighborhood of a magnet, electric current, or

changing electric field in which magnetic forces are observable. A magnetic field is
produced by moving electric charges and intrinsic magnetic moments of elementary
particles associated with a fundamental quantum property known as spin. Magnetic
field and electric field are both interrelated and are components of the electromagnetic
force, one of the four fundamental forces of nature. The magnetic field is the area
around a magnet in which the effect of magnetism is felt. We use the magnetic field
as a tool to describe how the magnetic force is distributed in the space around and
within something magnetic in nature.

The stronger the magnetic field, the greater the

number of lines of flux
Figure 2 Magnetic Flux Properties

I.3 Electromagnetism

Many common electronic devices contain electromagnets. An electromagnet is a coil

of wire wrapped around a bar of iron or other ferromagnetic material. When electric
current flows through the wire, it causes the coil and iron bar to become magnetized.
An electromagnet has north and south magnetic poles and a magnetic field. Turning
off the current turns off the electromagnet. To understand how electromagnets are
used in electric devices, we’ll focus on two common devices: doorbells and electric
motors like the one that turns the blades of a fan.

The strength of the magnetic field is directly proportional

to the amount of current flowing through the conductor

Figure 3 Fleming's Left-Hand Rule

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 Motors: Operations and Maintenance and Best Practices

The left-hand conductor rule is essential rules applicable in magnetism and

electromagnetism. John Ambrose Fleming developed them in the late 19th century as
a simple way of working out the direction of electric current in an electric generator
or the direction of motion in an electric motor. It is important to note that these rules
do not determine the magnitude; instead show only the direction of the three
parameters (magnetic field, current, force) when the direction of the other two
parameters is known. If the thumb and first two fingers of the left hand are arranged at
right angles to each other on a conductor and the hand oriented so that the first finger
points in the direction of the magnetic field and the middle finger in the direction of
the electric current, then the thumb will point in the direction of the force on the
conductor.

I.4 Types of Motors

1.4.1 DC Motor

A direct current (DC) motor is an electrical machine that converts electrical

energy into mechanical energy by producing a magnetic field generated by direct
current. When a direct current motor is turned on, a magnetic field is formed in its
stator. The field attracts and repels magnets on the rotor, causing it to revolve. The
commutator, which is coupled to brushes connected to the power source, supplies
current to the motor's wire windings in order to maintain the rotor revolving
continuously.

When electric current passes

through a coil in a magnetic field,
the magnetic force produces a
torque which turns the DC motor

Figure 4 DC motor

One of the advantages of DC motors over other types of motors is their ability to
precisely adjust their speed, which is essential for industrial machines. DC motors
can start, stop, and reverse instantly, which is critical for managing the operation
of manufacturing equipment.

Figure 5 DC motor view

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 Motors: Operations and Maintenance and Best Practices

1. Brushed DC motor

DC motors generate a magnetic field by winding wire coils. In a brushed

motor, these coils are free to rotate and drive a shaft; they are the "rotor" of the
motor. The coils are usually coiled around an iron core, although there are also
"coreless" brushed motors with self-supporting wrapping. The "stator" is the
motor's permanent component. Permanent magnets are used to create a
magnetic field that is stationary. These magnets are often placed on the inner
surface of the stator, outside of the rotor.

Figure 6 Brushed DC motor

A brush DC motor generates a magnetic field by passing current via a

commutator and brush linked to the rotor. Brushes are constructed of carbon
and may be stimulated singly or simultaneously. The stator is the container
that houses the motor's components and the magnetic field. The coil on the
rotor can be coiled in series or parallel to generate a series wound DC motor or
a shunt wound DC motor.

2. Brushless DC motor

Brushless DC motors work on the same magnetic attraction and repulsion

principle as brush motors, but they are built differently. Instead of a
mechanical commutator and brushes, electronic commutation rotates the
stator's magnetic field. Active control electronics are required for this. A
brushless motor has permanent magnets attached to the rotor and windings on
the stator. Brushless motors can be built with the rotor on the inside of the
windings, as illustrated above, or with the rotor on the outside.

Figure 7 Brushless DC motor

Brushless direct current motors are made up of a permanent magnet rotor and
a coil wrapped stator. Brushes are not required in this DC motor design. The
benefit of a brushless DC motor is that it eliminates brush wear and tear since
the moving magnet produces very little heat. Brushless DC motors are costlier
due to their efficiency.

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 Motors: Operations and Maintenance and Best Practices

1.4.2 AC motor

An alternating current motor (AC motor) is a type of electric motor that comprises
of a stator and a coil that is powered by alternating current to transform electric
current into mechanical power. The stator is the motor's fixed component, while
the rotor is its revolving component. Single-phase or three-phase AC motors are
available, with three-phase motors mostly utilized for bulk power conversion.
Single phase alternating current motors are utilized for low-power conversions.

Figure 8 Ac motor

AC motors are classified into two types: synchronous and induction. In a

synchronous motor, the shaft rotates at the same rate as the supplied current
frequency, thanks to multiphase AC electromagnets on the stator that generate a
revolving magnetic field. An induction motor, also known as an asynchronous
motor, is a single excited motor in which current is supplied to only one
component of the motor, the stator. Flux from the stator short circuits the short-
circuited coil in the rotor, creating torque that causes the rotor to revolve.

Figure 9 AC motor view

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 Motors: Operations and Maintenance and Best Practices

1. Induction Motor

In an induction machine, the armature winding functions as both the armature

winding and the field winding. Flux is formed in the air gap when the stator
windings are linked to an alternating current supply. The flux rotates at a
consistent pace, which is referred to as synchronous speed. Voltages are
created in the stator and rotor windings as a result of the revolving flux.

Induction Motor
Figure 10 Induction motor

When the rotor circuit is closed, current flows through the rotor winding and
reacts with the spinning flux, producing torque. The rotor rotates at a speed
extremely near to synchronous speed in the steady condition.

2. Synchronous motor

A synchronous motor is a motor that transforms alternating current electrical

power into mechanical power and operates exclusively at synchronous speeds.
When power is applied to a synchronous motor, a rotating field is created.
This field attempts to drag the rotor with it but is unable to do so due to rotor
inertia. As a result, no beginning torque is created. As a result, an intrinsically
synchronous motor is not self-starting.

Synchronous Motor
Figure 11 Synchronous motor

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 Motors: Operations and Maintenance and Best Practices

1.5 Key Components

1.5.1 DC motor

1. Field Poles
The magnetic poles of a DC motor are screwed into the inside wall of the
yoke. Magnetic poles are made up of two pieces. The pole core and pole shoe
are piled together under hydraulic pressure and then joined to the yoke. The
pole core has a limited cross-sectional area and serves just to keep the pole
shoe over the yoke, whereas the pole shoe has a relatively greater cross-
sectional area and spreads the flux produced over the air gap between the
stator and rotor to decrease reluctance loss. The pole shoe also has slots for the
field windings that generate the field flux.

Figure 12 Field Pole

2. Armature
The armature winding of a DC motor is connected to the rotor, or the spinning
portion of the machine, and as a result is subjected to a changing magnetic
field in the route of its revolution, resulting in magnetic losses. As a result, the
rotor is built of an armature core consisting of numerous low-hysteresis silicon
steel laminations to decrease magnetic losses such as hysteresis and eddy
current loss. The cylindrical structure of the armature core is formed by
stacking these laminated steel sheets together.

Figure 13 Armature winding

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 Motors: Operations and Maintenance and Best Practices

3. Commutator
The commutator of a direct current motor is a cylindrical construction
comprised of copper segments stacked together but separated by mica. As far
as the DC motor is concerned, its primary duty is to commute or relay the
supply current from the mains to the armature winding housed over a spinning
structure via the brushes of the DC motor.

Figure 14 Commutator

1.5.2 AC motor

Figure 15 2 Parts of AC motor

1. Rotor
Unlike a DC motor, the rotor of an AC motor is not connected to any external
power source. It gets its energy from the stator. The rotor of a three phase
induction motor can be squirrel cage or wound.
a. Induction Motor
The rotor in the squirrel cage variant is made up of rotor bars with end
rings at both ends. The squirrel cage rotor is available in split phase,
capacitor start, capacitor start and run, permanent split phase capacitor
run, and shaded pole configurations with A, B, C, D, and E classes.
The squirrel cage is almost often composed of aluminum or copper.

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Motors: Operations and Maintenance and Best Practices

Squirrel Cage Motor

Figure 16 Squirrel cage motor

The rotor bars interact with the electromagnetic field of the stator
during squirrel cage motor operation (EMF). As the current fluctuates,
so does the EMF, forcing the rotor to revolve and generate rotational
motion. The rotor does not revolve at the same frequency as the AC
current and is continually attempting to catch up, which is how the
rotation is created. If the frequencies were the same, the rotor would
freeze and there would be no motion.

Parts of Squirrel Cage Motor

Figure 17 Parts of Squirrel Cage motor

b. Synchronous Motor
The primary distinction between synchronous and induction motors.
The rotor of a synchronous motor moves at the same speed as the
revolving magnetic field of an induction motor. This is achievable
because the magnetic field of the rotor is no longer generated. When
met with another magnetic field, the rotor's permanent magnets or DC-
excited currents are forced to lock into a specific position.

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 Motors: Operations and Maintenance and Best Practices

2. Stator
A revolving magnetic field is produced by the stator. It features a solid metal
axle, a wire loop, coils, a squirrel cage, and connectors. Though squirrel cages
are not present in all AC motors, they are the most frequent. Electricity is sent
directly to the stator's outer coils in alternating current motors. The stator is
made up of numerous plates connected by copper magnetic wire that stretch
out from its center.

Figure 18 Stator

a. Induction Motor

The stator is the motor's stationary component that produces a rotating

magnetic field that interacts with the rotor. A "pole" within the stator is
made up of one or more copper windings, and a motor always has an
odd number of poles. The electric current alternates between the poles,
resulting in a revolving magnetic field.
b. Synchronous Motor

The stator has the same number of poles as the rotor and is powered by
a three-phase alternating current source. The three-phase alternating
current source generates a revolving magnetic field in the stator.

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 Motors: Operations and Maintenance and Best Practices

1.6 Safety Issues

Motors can be purchased for varying application areas such as for operating in a
potentially gaseous or explosive area. When purchasing a motor, be sure to check the
classification of the area, you may have a motor that does not meet the classification it
is presently in.

Figure 19 Safety issues

Electric motors are a major driving force in many industries. Their compact size and
versatile application potentials make them a necessity. Motors are chosen many times
because of the low vibration characteristics in driving equipment and of the potential
extended life of the driven equipment. The higher rpm and small size of a motor will
also make it a perfect fit for many applications. These were developed because of the
chemical plant setting in which highly corrosive atmospheres were deteriorating steel
housings. They are, for the most part, the same motors but have an epoxy or
equivalent coating.
1.7 Cost and Energy Efficiency
An electric motor performs efficiently only when it is maintained and used properly.
Electric motor efficiencies vary with motor load, the efficiency of a constant speed
motor decreases as motor load decreases. Below are some general guidelines for the
efficient operations of electric motors.
a. Sizing motors is important – Do not assume an existing motor is properly sized for
its load, especially when replacing motors. Many motors operate most efficiently
at 75% to 85% of full load rating. Under-sizing or over-sizing reduces efficiency.
For large motors, facility managers may want to seek professional help in
determining the proper sizes and actual loadings of existing motors. There are
several ways to estimate actual motor loading: the kilowatt technique, the
amperage ratio technique, and the less reliable slip technique.

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 Motors: Operations and Maintenance and Best Practices

b. Replacement of motors versus rewinding – Instead of rewinding small motors,

consider replacement with an energy-efficient version. For larger motors, if motor
rewinding offers the lowest life-cycle cost, select a rewind facility with high-
quality standards to ensure that motor efficiency is not adversely affected. For
sizes of 10 HP or less, new motors are generally cheaper than rewinding. Most
standard efficiency motors under 100 HP will be cost-effective to scrap when they
fail, provided they have sufficient run-time and are replaced with energy-efficient
models.
c. Turn off unneeded motors – Locate motors that operate needlessly, even for a
portion of the time they are on and turn them off. For example, there may be
multiple HVAC circulation pumps operating when demand falls, cooling tower
fans operating when target temperatures are met, ceiling fans on in unoccupied
spaces, exhaust fans operating after ventilation needs are met, and escalators
operating after closing.

Figure 20 Energy Losses

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 Motors: Operations and Maintenance and Best Practices

1.8 Maintenance of Motors

The goal of predictive maintenance programs is to reduce maintenance costs by detecting

problems early, which allows for better maintenance planning and fewer unexpected
failures. Predictive maintenance programs for motors observe the temperatures, vibrations,
and other data to determine a time for an overhaul or replacement of the motor (Barnish et
al. 2001).

Figure 21 Maintenance of Motors

Preventative and predictive maintenance programs for motors are effective practices in
manufacturing plants. These maintenance procedures involve a sequence of steps plant
personnel use to prolong motor life or foresee a motor failure. The best safeguard against
thermal damage is avoiding conditions that contribute to overheating. These include dirt,
under and over-voltage, voltage unbalance, harmonics, high ambient temperature, poor
ventilation, and overload operation.

1.9 Diagnostic Equipment

1.9.1 Thermography
An infrared thermometer or camera allows for an accurate, non-contact
assessment of temperature. Applications for motors include bearing and electrical
contact assessments on motor systems and motor control centers.

Figure 22 Thermography

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 Motors: Operations and Maintenance and Best Practices

Thermography detects infrared energy emitted by an electrical circuit or an

electrical part through which an electrical current passes (wire, cable, transformer,
contactor, electrical motor, breaker, etc.)

Figure 23 Thermography Infrared

1.9.2 Ultrasonic analyzer

Electric motor systems emit very distinct sound patterns around bearings. In most
cases, these sounds are not audible to the unaided ear or are drown-out by other
equipment noises. Using an ultrasonic detector, the analyst is able to isolate the
frequency of sound being emitted by the bearing. Changes in these ultrasonic
wave emissions are indicative of changes in equipment condition-some of these
changes can be a precursor to component degradation and failure.

Figure 24 Ultrasonic analyzer

a. An ultrasonic motor rotates a rotor by using ultrasonic waves with high

frequencies more than 20,000Hz which a human cannot hear. The ultrasonic
motor generates ultrasonic waves using piezoelectric elements, while
conventional motors use permanent magnets or coils to rotate a rotor.

b. Ultrasonic testing is done in materials to determine whether there are flaws or

defects present in a material, and also to determine the thickness of a material.
Ultrasonic testing methods use sound waves to find defects and measure
thickness.

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 Motors: Operations and Maintenance and Best Practices

1.9.3 Vibration Analyzer

The rotational motion within electric motors generates distinct patterns and levels
of vibration. Using a vibration analyzer and signature analysis software, the
analyst can discern the vibration amplitude of the point on the motor being
monitored. This amplitude is then compared with trended readings. Changes in
these readings are indicative of changes in equipment condition.

Figure 25 Vibration analyzer

Vibration may influence the durability and reliability of machinery systems or

structures and cause problems such as damage, abnormal stopping and
disaster. Vibration measurement is an important countermeasure to prevent
these problems.
1.10 Available Software Tools
1.10.1 MotorMaster+ Version 4.0 for Motor Replace/Rewind Decisions
MotorMaster+ Version 4.0 for Motor Replace/Rewind Decisions Developed by
the DOE Industrial Technologies Program, this software tool handles everything
from calculating the simple payback on a single motor purchase to
comprehensive, integrated motor system management.

Figure 26 Motor Master

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 Motors: Operations and Maintenance and Best Practices

1.11 Relevant Operational Energy Efficient Measures

1.11.1 Replace Standard Motors with Energy Efficient Motors

High efficiency motors have been designed specifically to increase operating

efficiency compared to standard motors. Design improvements focus on reducing
intrinsic motor losses and include the use of lower-loss silicon steel, a longer core
(to increase active material), thicker wires (to reduce resistance), thinner
laminations, smaller air gap between stator and rotor, copper instead of aluminum
bars in the rotor, superior bearings and a smaller fan, etc.

1.11.2 Sizing to Variable Loads

The biggest risk is overheating of the motor, which adversely affects the motor
life and efficiency and increases operating costs. Proper sizing is a crucial aspect
of motor selection. If a motor is undersized, it will not be able to control the load,
leading to overshoot and ringing. If the motor is oversized, it may control the load
but it will also be larger and heavier, as well as more expensive in terms of price
and cost of operations.

1.11.3 Improving Power Quality

Voltage unbalance can be even more detrimental to motor performance and occurs
when the voltages in the three phases of a three-phase motor are not equal. Good
power quality saves money and energy. Direct savings to consumers come from
lower energy cost and reactive power tariffs. Indirect savings are gained by
avoiding circumstances such as damage and premature aging of equipment, loss of
production or loss of data and work.

1.11.4 Improving Maintenance

Most motor cores are manufactured from silicon steel or de-carbonized cold-rolled
steel, the electrical properties of which do not change measurably with age.
However, poor maintenance can cause deterioration in motor efficiency over time
and lead to unreliable operation. For example, improper lubrication can cause
increased friction in both the motor and associated drive transmission equipment.
Resistance losses in the motor, which rise with temperature, would increase.

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1.11.5 A Checklist of Good

a. Inspect motors regularly for wear in bearings and housings (to reduce
frictional losses) and for dirt/dust in motor ventilating ducts (to ensure proper
heat dissipation.
b. Check load conditions to ensure that the motor is not over or under loaded. A
change in motor load from the last test indicates a change in the driven load,
the cause of which should be understood.
c. Lubricate their motors. Inadequate lubrication can cause problems. Over
lubrication can also create problems, e.g. excess oil or grease from the motor
bearings can enter the motor and saturate the motor insulation, causing
premature failure or creating a fire risk.
d. Check periodically for proper alignment of the motor and the driven
equipment. Improper alignment can cause shafts and bearings to wear quickly,
resulting in damage to both the motor and the driven equipment.
e. Ensure that supply wiring and terminal box are properly sized and installed.
Inspect regularly the connections at the motor and starter to be sure that they
are clean and tight.
f. Provide adequate ventilation and keep motor cooling ducts clean to help
dissipate heat to reduce excessive losses. The life of the insulation in the motor
would also be longer: for every 10°C increase in motor operating temperature
over the recommended peak, the time before rewinding would be needed is
estimated to be halved.

1.11.6 Multi Speed Motors

Motors can be wound such that two speeds, in the ratio of 2:1, can be obtained.
Motors can also be wound with two separate windings, each giving two operating
speeds and thus a total of four speeds. Multi-speed motors can be designed for
applications involving constant torque, variable torque, or for constant output
power. Multi-speed motors are suitable for applications that require limited speed
control (two or four fixed speeds instead of continuously variable speed). These
motors tend to be very economical as their efficiency is lower compared to single-
speed motors.

1.11.7 Variable Speed Drives (VSDs)

They are designed to operate standard induction motors and can therefore be
easily installed in an existing system. They are designed to operate standard
induction motors and can therefore be easily installed in an existing system.

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1.12 Electric Motors Checklist

Table 1 Motor Checklist

Maintenance Frequency
Description Comments
Daily Weekly Monthl Annually
y
Motor Turn off/sequence
use/sequencing unnecessary motors

Complete overall visual

Overall visual inspection to be sure all
Inspection equipment is operating
and safety systems are in
place

Check the condition of the

Motor Condition motor through
temperature or vibration
analysis and compare to
baseline values

Assure that all bearings

Check are lubricated per the
lubrication manufacture’s
recommendation

Check packing for wear

Check packing and repack as necessary.
Consider replacing
packing with mechanical
seals
Aligning the motor
coupling allows for
Motor alignment efficient torque transfer to
the pump

Check and secure all

Check motor mountings
mountings

Tighten connection
Check terminal terminals as necessary
tightness

Remove dust and dirt

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 Motors: Operations and Maintenance and Best Practices

Cleaning from motor to facilitate

cooling.

Check bearings Inspect bearings and drive

belts for wear. Adjust,
repair, or replace as
necessary.

Checking the condition of

Motor condition the motor through
temperature or vibration
analysis assures long life.

Check for Unbalanced power can

balanced three- shorten the motor life
phase power through excessive heat
build up
Over-voltage or under-
Check for over- voltage situations can
voltage or under- shorten the motor life
voltage through excessive heat
conditions build up

1.13 Motor Energy Audit

1.13.1 What is a Motor Energy Audit?
Motor energy auditing seeks to assist industrial energy users, energy consultants,
and to fulfill their objectives of conserving energy in the industrial sector,
corporations and engineers. As a result, a methodology for energy audits of motor-
driven systems has been established, based on tools and international standards, to
make it easier to identify opportunities for energy savings in the area of industrial
electric motor systems. Combining theory with practice in the area of energy
auditing is one of the key goals of this report. The major attributes of this energy
audit approach should be its applicability, simplicity of use, and sound structure.
The energy audit methodology is structured into the following seven steps:
1. Energy audit planning
2. Opening meeting & Data collection
3. Measurement plan
4. Data-Analysis
5. Energy Audit reporting
6. Closing meeting

1.13.2 Relevant tools

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Numerous analysis- and calculation tools have been created globally to aid the
work of energy auditors. It is essential to choose the required tools before
explaining and putting the various tools in the audit technique. The following
factors form the basis of the tool selection process: The following tools have been
selected according to the above mentioned criteria.
1. SOTEA
In one factory, the efficiency potential of motor systems is evaluated using
SOTEA ("Software Tool for Efficient Drives"). The industrial user is intended
to receive an approximate estimate of the amount that might be saved, which
mostly depends on the age of the existing motor stock.
2. ILI+
A list of motors is created using ILI (Intelligent Motor List). For refit, the
motors with the largest potential for savings might be chosen. The tool's
"Decision Maker" assists the users and discovers a small number of motors
that account for a large portion of the potential savings.
3. STR
The STR (Standard Test Report) is a standardized form for a motor system
analysis process that aids in summarizing test findings and suggesting motor
system efficiency measurers along with the anticipated expenses and savings.
4. EMSA
The Electric Motor System Annex of the International Energy Agency (IEA-
4E) created the Motor System Tool to determine the efficiency of a whole
motor system (motor plus VFD, gear and transmission). It aims to support
engineers, machine builders, machine component suppliers, energy
consultants, and others engaged in machine system optimization for the
purpose of achieving lower power usage.
1.13.3 Phase one - Energy audit planning
The first stage of the technique for an energy audit of systems that use motors is
the scheduling an energy assessment. In this stage, the audited firm and the energy
auditor are tasked for creating and defining the energy audit's parameters. This
chapter assists energy auditors in providing prompt, accurate answers to the
inquiries. In the first meeting, further queries will be covered. The planning stage
of an energy audit may be divided into two distinct sections.
a. Gathering general information on the company/factory/business
The energy auditor should compile broad data on the company. Due to
the wide range and lack of definition in the questions that should be
asked, this is not usually particularly simple. A checklist has thus been
created to assist the energy auditor in his task.

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Table 2 Checklist - General Information

Company Profile
Company name:
Address 1: Telephone:
Address 2: Fax:
City town: E-mail:
Region/country:
Post/zip code:
Electric motor system site address
Address 1:
Address 2:
City/town:
Region/country :
Post/zip code:
In which industrial sector:
Food Textile/- Wood/paper/ Chemical- Rubber
clothing print /Pharma and
industry plastic
products
Mechanical Auto-motive Electrical Glas/stone/ Supply/
Engineering industry engineering/ earth disposal
/metal electronics
construction
Power Building Basic materials industry
engineering technology
For what the electric motor systems are used?
------------------------------------------------------------------
Number of employees
-------------------------------------------------------
How many shifts there are?
-----------------------------------------------------
Working time
Weekday Time Weekday Time
Mon
Tue
Wed
Thurs
……… annual operating hours
Contact person
Name:
Function:
Address:
Phone:

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The majority of the data for the aforementioned Table should be able
to be entered by the Energy Auditor by himself. If there is still
information missing, a brief phone call to the relevant firm should give
prompt assistance to finish the check list.
b. Pre-Screening (estimation of energy saving potential related to
electric motor systems)
The prescreening, which reveals if an audit is necessary in the area of
electric motor systems, is one of the most important phases of an
energy audit's planning phase. Calculations and extra technical and
financial information are needed in order to assess the company's
electrical motor systems' potential for energy savings. Energy auditors
can thus benefit from "SOTEA," a free software application created by
topmotors.ch, in regards to this topic. It is possible to assess whether
the firm needs an electric motor energy audit by inputting pertinent
data into the application.

Figure 27 SOTEA Input-interface

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After data submission, SOTEA may determine and compute the

prospective energy efficiency of the electric motor systems in the
corresponding firm. Energy consumption numbers are generated
automatically by the tool and are displayed on the "User estimate" tab
according to the input, which is where the tool automatically divided
the input. The user may additionally modify these various settings in
order to provide a more precise estimate of the energy use.

1.13.4 Phase Two - Opening meeting & data collection

1. Opening Meeting

The opening meeting between the corporate representative and the energy
auditor should take place in person. The energy auditor should notify those
who are interested in the energy-saving potential of electric motor systems, the
audit scope that has to be further defined, boundaries, and techniques, as well
as the site safety inductions, in this stage.
a. Invite right representatives to the opening meeting
b. Preparation of documents for the meeting
c. Convince the top-management
d. Define scope, boundaries and methods of the energy audit
e. Assign personnel to assist the energy auditor
f. Ensure the cooperation of the affected parties
g. Confirm any unusual conditions
h. Arrangements for access
i. Requirements for health, safety and security
j. Availability of financial resources
k. Requirements and procedures to be followed for installation of
measuring equipment
l. An action plan for the assessment shall be developed
m. Agreed by the assessment team and top-management

2. Data collection

The opening meeting's time spent on site can immediately be put to use to
begin the data collecting. The primary benefit of collecting data early is that
fewer meetings need to be scheduled in order to do it.

Data collection

General Data Technology-specific data

Collection collection
Table 3 Classification in two levels of the step

Electric Motors

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a. General data collection

The preliminary examination of the available data pertaining to electric

motor powered systems is the first phase in the data gathering process. In
order to analyze existing electric motor driven systems with an eye on
energy efficiency and the possibility for improvement measures, a tool
known as "Intelligent Motor List" (ILI+) may be utilized.

b. Technology- specific data collection

The detailed data collection should concentrate on motors with the
following characteristics.
i. Big Equipment
ii. Old Equipment
iii. Long Down times
iv. Varying duties but fixed speed
v. Support Equipment
vi. Problem Equipment
First, general information about the electric motor system should be
gathered, such as coupling type, motor type (AC or DC), manufacturer,
etc. The second step involves gathering technical and detailed information
about the electric motor system, such as synchronous speed, full load
efficiency, full load amperage, enclosure type, full load power factor, etc.
The comprehensive operating profile of the electric motors is the subject
of the final section of the particular data collection.
The necessary information for the particular data collection of industrial
electric motors is included in all tables, along with examples and the
associated units. The tables may be used as a type of checklist and can
assist the energy auditor in gathering the necessary information with
effectiveness.

Table 4 General data of the electric motor system

General motor data

Required Data Example Unit
Coupling type (belt, Direct -
gear, direct, etc.)
Motor type (Design DC -
AC or DC, etc.)
Motor history Original -
(Original, rewound or
replaced)

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Table 5 specific/technical data of the electric motor system

General motor data

Required Data Example Unit
Manufacturer Siemens AG -
Motor ID number GP 1LE1523 -
Model SIMOTICS GP 1LE1 – -
Eagle Line
Serial Number 136521445 -
Power 160 kW
Full load speed 1791 min^-1
Full load voltage 230/400 (star- or delta V
circuit)
Full load ampere 225 A
Full load power factor 0.87 -
Full load efficiency (4/4) 96.2 %
Part load efficiency (3/4) 96.2 %
Part load efficiency (2/4) 95.7 %
Efficiency class (if IE3 -
provided)
Frame designation 315 L -
Unusual operating nothing detected -
conditions

Table 6 Detailed operating profile of the electric motor system

Operating profile motor data

Weekdays Weekend/Holiday
Days/Year_____ Days/Year_____

Hours per day 1st shift ________ ________

2nd shift ________ ________
3rd shift________ ________

Annual operating time________ hours/year

Thereof:
Part load________ %
Full load ________ %

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1.13.5 Phase Three - Measurement Plan

The measuring plan is addressed by the energy audit technique. On-site data
collection may be required to conduct an energy audit. It is advised that the
auditor and the organization come to an agreement on a measuring strategy. This
strategy depends on the measurement's goal.

1. Relevant points which should be included in the measurement plan

a. Use of measurement instrument/equipment

The first step deals with the usage of the right measurement
instruments/equipment.
b. Data measurement
The second step deals with the measurement process itself, the provision
of additional variables and adjustment of factors.
c. Preliminary data treatment
The right treatment of measurement data is part of the third stage of the
implementation of the measurement plan

2. Relevant measurement equipment for MDS

Another crucial component of the measurement strategy is the choice of the
appropriate measuring tool.

Table 7 Recommended measurement methods and equipment for motor driven systems

Application Recommended measuring Recommended measuring

system (portable) system (stationary)

Electric motor Electrical power Electrical power

consumption: consumption:
 True RMS-Power meter  True RMS-Power meter

1.13.6 Phase Four- Data – Analysis

The energy auditor should be able to analyze the available data once they have
collected the energy-specific data and taken the necessary measurements. The
analysis' primary goal is to identify the best energy-saving strategies for the given
technology.
1. Energy Audit Tools for Data-Analysis
a. EMSA-Motor-System-Tool
Energy management and optimization of motor-driven systems involves
identifying opportunities for energy savings, selecting the best
components, and getting them to operate well together. There are various
parts to an electric motor system, all of which must work together in
harmony. Extensive calculations are needed to estimate the benefits of
greater energy efficiency during a new installation as well as the
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optimization of an old, existing electric motor system. The Motor System

Tool was created by EMSA to aid technicians and energy auditors in
system improvement.

Figure 28 Screenshot Motor Systems Tool

The basic function of the Motor-Tool can be summarized as follows:

The user defines a working point of the electrical motor system, e.g. the
speed or the required load. From this point on, all efficiency factors can be
calculated. The next step involves assessing the efficiency by changing
various parameters. The output of the tool is the energy consumption of
the defined system.

b. STR-Standard Test Report

The "Standard Test Report" is another instrument that may help the energy
auditor with their examination of energy. This tool is used to consistently
document the current and desired states of motor-driven systems (both
before and after the application of improvement strategies). In the
following paragraph the main function and features of the STR-tool will be
described.
i. Detailed description of the actual state of the electric motor driven
system.
ii. Results of electrical load measurement
iii. Rough costs of the individual energy improvement measures
iv. Calculation of the energy demand of the total system in the actual and
the target status
v. Box for additional explanations
The STR-fundamental Tool's purpose may be summed up as follows:
The Excel application can assist the energy auditor in gathering the
appropriate motor system data and in doing a system and component
efficiency analysis. Additionally, the software can calculate the expenses

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of the entire motor system in both the existing and the desired states, and
the energy auditor may simulate various energy-saving techniques.

2. Energy Saving Measures

a. Electric Motors
i. Measure 1: Motor replacement
a replacement of the old motor can take place; it has to be checked.
The following criteria are important for the implementation of this
measure:
a. high run-times of the electric motor
b. high age of the electric motor
c. low efficiency factor of the electric motor
The most crucial thing to understand is that, depending on the
power range, the A motor's efficiency factor ranges from 80% to
93%. Greater efficiency is possible for motors with higher power
ranges.
According to the international standard IEC 60034-30-1:2014
electric motors can be divided into the following efficiency classes:
a. IE1 – Standard Efficiency
b. IE2 – High Efficiency
c. IE3 – Premium Efficiency
d. IE4 – Super Premium Efficiency
.

ii. Figure 29 Scope of IEC 60034-30-1

Measure 2: Control and performance adjustment
Controlling and optimizing the performance of electric motors is
another crucial step in reducing costs and energy consumption.
Particularly, the use of frequency converters can significantly
lower energy consumption.
iii. Measure 3: Maintenance and repair
By taking the appropriate steps, a significant amount of energy
may be saved when it comes to the upkeep and repair of electric

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motors. The two major goals of maintenance historically have been

to prevent early failure of equipment and to maintain the
equipment's performance calibration. Preventative maintenance
may be used to describe both of these goals.

The following activities should be executed in order to have an

effective maintenance plan in the field of electric motors:
a. Cleaning
b. Lubrication
c. Correct mounting, coupling and alignment
d. Optimize operating conditions
e. Thermal, vibration and acoustic tests
f. Electrical tests

1.13.7 Energy Audit Reporting

1. Executive summary:
An overview of the whole energy audit procedure will be given in the executive
summary. Because the management will read the executive summary first, it is
advised to keep the summary to the essentials and to stress the financial benefits.
2. Introduction and facility information:
This section of the report should include a brief description of the background, the
team and scope of the electric motor audit.
3. Description of system(s) studied in assessment and significant system issues
The report shall include a detailed description of the specific motor systems on
which the assessment was performed. Depending on the system assessed, the
discussion of system operation can be extensive and should be supported by
graphs, tables and system schematics.
4. Assessment data collection and measurements:
Key facility people must be identified and interviewed, data must be collected,
and measurements must be conducted. A summary of the measurement strategy
must also be provided. Include the following pertinent information:
a. Definition of system requirements and a determination of how system
b. Operation changes during the year (drawings, system process data)
c. Electrical energy consumption data
d. Other specific data relating to the motor driven systems such as pump
e. Total head, specific fan power, working pressure, flow, etc.
f. Determination of operating hours of the motor systems
g. Performance information of the motor system when available
h. Measurement or estimation of system losses
5. Data Analysis
The report ought to include notice of the findings of the measurements and data
analysis. Documentation must be kept for all major analytical techniques,
measurements, observations, and conclusions from data analysis of accomplished

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action items.

6. Annual energy consumption baseline:

The evaluation report must include the baseline of the entire yearly energy
consumption for the motor-driven system if there are enough data to do so. The
analytical process that was utilized to create the baseline for yearly energy use
will also be discussed.
7. Performance improvement opportunities identification and prioritization:
Estimates of energy reduction and cost savings from suggested performance
opportunities must be quantified in the report's main section. Other energy- and
non-energy-related advantages might be accounted for via additional
computations.
8. Recommendations for implementation activities:
After determining which energy-saving solutions should be prioritized, the energy
auditor should provide some suggestions for actionable implementation strategies
in the report. As a result, only the most essential energy-saving strategies should
be identified and well described.
9. Appendices
In order to guarantee that the body of the report is clear, this section should
contain material that is long and not necessary for the presentation of the report.
The report appendices should contain references to and comprehensive supporting
data, such as energy consumption figures, cost savings calculations, and economic
analyses.

1.14 Standard Testing for Motors

1.14.1 Motor Testing

Specific testing assesses the integrity of a motor through the use of computer-
supported equipment or tools that monitor trends within the motor. The main
objective of motor testing is to reveal hidden problems and prevent unnecessary
failure. Specific to electric motors, motor testing evaluates static parameters like
insulation, wire damage and electrical current leakage, as well as more dynamic
parameters such as distortion, temperature fluctuations and balance.
1.14.2 IEEE Standards
Motor testing is regulated by the Institute of Electrical and Electronics Engineers
(IEEE) through standards. IEEE standards and test procedures are widely used by
motor and generator vendors and users to commission windings in new machines,
as well as evaluate the condition of the winding insulation in operating machines.
Until recent revisions, the basic procedures and standards in use were written over
25 years ago. Since the 1970s, motor windings have encountered many changes in
their design and manufacture. The result was that the interpretation of results in
many of the standards was no longer valid for the more modern motors. Over the
past five years, the IEEE Power Engineering Society has conducted a major
review and updating of most of these standards. Many important changes in test
procedures and interpretation guidelines have resulted. Today, the IEEE lists the
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following recommended practices, and guides that are used by both manufacturers
and users such as:

a. IEEE 43-2000: insulation resistance and polarization index (new and aged
windings);
b. IEEE 56-1977: ac hipot tests (aged windings);
c. IEEE 95-2002: dc hipot tests (new and aged windings);
d. IEEE 286-2000: power factor (PF) tip-up tests (new and aged windings);
e. IEEE 522-2004: hipot tests for turn insulation (new and aged windings);
f. IEEE 1434-2000: partial discharge (PD) tests (new and aged windings).

1.14.3 Types of Motor Testing

a. Online Dynamic Testing

This is done while the motor is running. It gives technicians data on the
power quality and operating condition of the motor. Dynamic testing
equipment should be able to collect and trend all data essential to electric
motors. This includes power condition, voltage level, voltage imbalance
and harmonic distortions, current levels and imbalances, load levels,
torque and rotor bar signatures, etc. Analyzing the collected data from
online testing can reveal problems through indicators such as power
condition, motor condition and performance, load assessment, and
operating efficiency.

Figure 30 Screenshot of dynamic testing

b. Offline Static Testing

This should be used on a regular basis to determine how the components
within a motor (windings, rotor bar, etc.) are functioning as well as to
perform a current and voltage analysis. Static testing often finds problems
like broken or loose rotor bars, issues with end rings, an unequal air gap
between the rotor and stator (eccentricity), and misalignment. As the name
suggests, this type of motor testing is done when the machine is stopped.
Static testing assesses things like resistance/insulation resistance, high-
potential (HiPot) tests, polarization, surge tests and more.

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Figure 31 Static testing

Nearly half (48 percent) of all motor failures are due to electrical issues,
according to a survey by the Electric Power Research Institute (EPRI). Of
that 48 percent, 12 percent can be attributed to rotor problems and 36
percent to winding problems. To help mitigate these failures, a variety of
motor tests can be performed on electric motors. Some of the most
common include:
i. Electric Motor Impulse Testing: Testing helps you understand
how an electrical system can withstand sudden overvoltage
caused by weather (lightning strikes), regular duty situations
like when low- or high-voltage equipment changes operations,
or high-voltage variations in AC-DC inverter output.
ii. Insulation Resistance Testing: With electric motor insulation,
as temperature increases, resistance decreases. This is known as
a negative temperature coefficient. Testing the insulation helps
ensure the insulation resistance of a de-energized motor
decreases after starting the motor. It's not uncommon for the
temperature to increase initially as moisture evaporates from
the increasing temperature of the windings. Insulation
resistance testing needs a temperature rectification to 104
degrees Fahrenheit (40 Celsius), according to the IEEE 43
standard. (Applicable Standard: IEEE Std 43-2000)
iii. HiPot Test: Short for "high potential," a HiPot test checks for
good isolation or that no current flows from one point to
another point. Think of this as the opposite of a continuity test
(where current flows easily from one point to another). The
HiPot test verifies that insulation is adequate for the regularly
occurring over-voltage transient. This test is ideal for
identifying things like nicked or crushed insulation, stray wires,
braided shielding, conductive or corrosive contaminants, and
spacing problems, among others. (Applicable Standard: IEEE
Std 56-1977 & IEEE Std 95-2002)

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iv. Polarization index (PI) testing: This motor test is used to

determine the fitness of a motor. The index is made up of
calculating the measurement of the winding insulation
resistance. The PI gives you an idea of how much dirt or
moisture buildup there is, the insulation integrity and how well
the motor operates. For this test, the applied voltage should be
kept constant for 10 minutes, with an insulation resistance
reading taken at one minute and a second insulation resistance
reading taken at 10 minutes. The ratio between the one-minute
and 10-minute measurements gives you the polarization index.
(Applicable Standard: IEEE Std 43-2000(R2006))
1.14.4 Purposes of Mentioned Standards
a. IEEE 43-2000: insulation resistance and polarization index (new and
aged windings)
Describes a recommended procedure for measuring insulation resistance of
armature and field windings in rotating machines rated 1 hp, 750 W or
greater. It applies to synchronous machines, induction machines, dc
machines, and synchronous condensers. It does not apply to fractional-
horsepower machines.
b. IEEE 56-1977: ac hipot tests (aged windings)
The purpose of this IEEE standard is to present information necessary to
permit an effective evaluation of the insulation systems of large
alternating-current rotating electrical machines. Such an evaluation can
serve as a guide to the degree of maintenance or replacement which might
be deemed necessary, and also offer some indication of the future service
reliability of the equipment under consideration. The guide is intended to
apply in general to large alternating current rotating electrical machines
rated at 10000 kVA or more, and operating at voltages of 6000 V and
above.
c. IEEE 95-2002: dc hipot tests (new and aged windings)
This recommended practice provides uniform methods for testing
insulation with high direct voltage. It applies to stator (armature) windings
of ac electric machines rated 2300 V or higher. It covers acceptance testing
of new equipment in the factory or in the field after installation, and
routine maintenance testing of machines that have been in service.
d. IEEE 286-2000: power factor (PF) tip-up tests (new and aged
windings)
This recommended practice applies to stator coils or bars (half coils) of
electric machinery operating at any voltage level. It usually applies to
machines with a voltage rating of 6 kV and higher. Individual stator coils
outside a core (uninstalled), individual stator coils installed in a core, and
completely wound stators are covered in this recommended practice. The
tests apply to all coil insulation systems: pre-impregnated coils, post
impregnated coils (global impregnation), and fully-loaded (resin-rich)

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taped coils. This recommended practice is not applicable to non-

impregnated individual coils.

e. IEEE 522-2004: hipot tests for turn insulation (new and aged
windings)
The purpose of this guide is to make suggestions on testing the dielectric
strength of the insulation separating the various turns from each other
within multiturn form-wound coils to determine the acceptability of the
coils. Typical ratings of machines employing such coils normally lie
within the range of 200 kW to 100 MW. Test voltage levels described
herein do not evaluate the ability of the turn insulation to withstand
abnormal voltage surges, as contrasted to surges associated with normal
operation.
f. IEEE 1434-2000: partial discharge (PD) tests (new and aged windings)
This guide discusses both on-line and off-line partial discharge (PD)
measurements on complete windings of any type, as well as measurements
on individual form-wound coils and bars. Measurements selected from
those that are outlined may be appropriate for application during the
manufacture, installation, operation, and maintenance of windings of ac
rotating machinery.

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II. Abbreviations

AC - Alternating Current

DC - Direct Current

DOE - Department of Energy

EM - Electric Motor

EMSA - Electric Motor System Annex

Hp - Horse Power

Hz - Hertz

ILI - Intelligent Motor List

kW - Kilowatts

NEMA - National Electrical Manufacturers Association

RPM - Revolutions Per Minute

SOTEA - Software Tool for Efficient Drives

STR - Standard Test Report

VSDs - Variable Speed Drives

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III. Definition of Terms

Alternating Current - An electric current which periodically reverses direction and

changes its magnitude continuously with time in contrast to direct
current which flows only in one direction.
Armature - Is the winding of an electric machine which carries alternating
current.
Bearings - A machine element used to permit a rotary motion and transmit
the power between machine parts.
Commutator - This is mainly found in DC motors and has a purpose to overturn
the direction of the electric current.
Direct-Current - Is an electric current that is one-directional, so the flow of charge
is always in the same direction.
Electrical Insulation - Is a term used for a variety of materials used to reduce the transfer
of energy.
Electromagnetism - The physical interaction among electric charges, magnetic
moments, and the electromagnetic field.
Electromotive force - Is the electrical action produced by a non-electrical source,
measured in volts.
Energy Efficient Motor - A motor that gives you the same output strength by consuming
lessen amounts of power.
Field Coil - Is an electromagnet used to generate a magnetic field in an
electro-magnetic machine, typically a rotating electrical machine
such as a motor or generator.
Induction Motor - A motor with a three-phase AC motor and is the most widely used
machine.
Magnetic Field - A vector field that describes the magnetic influence on moving
electric charges, electric currents, and magnetic materials.
Magnetic Force - It is the basic force responsible for such effects as the action of
electric motors and the attraction of magnets for iron.
Motor - Is an electrical machine that converts electrical energy into
mechanical energy.
Motor Sizing - The process of picking the correct motor for a given load.
Multi-Speed Motors - A motor that will run at more than one speed depending on how
you connect it to the supply.
Predictive Maintenance - Usage of non-destructive tests such as infrared thermographic
studies and electric motor vibration analysis to electric motors
currently in service to identify possible problems so that
corrections can be made before they became serious problems.

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Preventive Maintenance - The objective of this kind of maintenance is to prevent operating

problems and make sure that the motor continuously provides a
reliable operation.
Rotor - In electrical motors or generators, the whole linear synchronously
rotating part of the machine is termed the rotor.

Synchronous Motor - A motor with an obvious characteristic of strict synchronism with

the power line frequency.
Stator - The stationary part of a rotary machine or device, especially in a
motor or generator.
Thermography - A camera or thermometer that allows for an accurate, non-contact
assessment of temperature.
Torque - The measure of the force that can cause an object to rotate about
an axis. Force is what causes an object to accelerate in linear
kinematics
Ultrasonic analyzer - This is used as a detector for analysts to be able to isolate the
frequency of sound being emitted by the bearing.
Variable Speed Drives - Also called as adjustable speed drives and can change the speed of
a motor and are available in a range from several kW to 750 kW.

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IV. Report Contents (PPT)

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V. References

 https://www.iqsdirectory.com/articles/electric-motor/dc-motors.html
 https://www.monolithicpower.com/en/brushless-vs-brushed-dc-motors
 https://www.iqsdirectory.com/articles/electric-motor/ac-motor.html
 https://circuitglobe.com/ac-motor.html
 https://www.electrical4u.com/construction-of-dc-motor-yoke-poles-armature-field-
winding-commutator-brushes-of-dc-motor/#Poles-of-DC-Motor
 https://sciencing.com/types-rotor-centrifuges-5912175.html
 https://ieeexplore.ieee.org/document/6515981?fbclid=IwAR2IuIAmKhzn7Znrp-
gouQ1W5ZSwGJD8278yhA-iA7U-v-_9MAXbv5MpTT8
 https://ieeexplore.ieee.org/document/913583?
fbclid=IwAR31Q6UDfpG_k6k0lf8_PnPRVQWNQ9PcXdGXHGKUW_jvpUkEEzT6ZrF
ZyMc

EE400 – EE41S1– S. Y. 2022-2023 MG1 49

 Motors: Operations and Maintenance and Best Practices

 https://ieeexplore.ieee.org/document/1322822?
fbclid=IwAR2hwAxDt_TQoEzfjB0nuKxP1_-
POZJXYGhQl091XQGxBDuWZrEfHf1hLIM
 https://ieeexplore.ieee.org/document/996345?
fbclid=IwAR1e1apAh3ZaKIIl_zg83sFujiDP9bPvHwWInrsR0pXFmVI_bzUr3NanoTU
 https://ieeexplore.ieee.org/document/863904?
fbclid=IwAR202KENNJSVGGE8CODlMBZwdho6FyACRVXo3h-
lAVI1l7eCodUu6Xq_cJw
 https://www.powerservicesgroup.com/2013/10/polarization-index-pi-test/?
fbclid=IwAR1zxpuLEsA8kcRTbiRjnsYSayLD6nW5A3VOIbc317J0ivnisYTRpgG21sI
 https://ieeexplore.ieee.org/document/6754111
 https://roshdsanatniroo.com/pdf/IEEE%20Std.%2043-2000.pdf?
fbclid=IwAR0wYuO4SwhokQHdG_3AaBXhT3E7yyj5tBpE7emhAYkG798cAYdHOug
Pwqo
 https://nachhaltigwirtschaften.at/resources/iea_pdf/reports/
iea_4e_emsa_energy_audits_for_motor_driven_systems_part1.pdf
 https://studyelectrical.com/2014/09/electric-motor-maintenance.html
 https://www.slideshare.net/hamadahamud/types-of-motors-ppt
 https://www.theengineeringprojects.com/wp-content/webp/2020/09/Introduction-to-
Electric-Motors-2.jpg.webp?ssl=1
 https://www.theengineeringprojects.com/2020/09/introduction-to-electric-
motors.html#:~:text=A%20motor%20is%20an%20electrical%20device%20that
%20converts%20electrical%20energy,Hans%20Christian%20Orsted%20in
%201820.
 https://www.slideshare.net/DavisLazarus/electric-motors-104320071
 https://www.slideshare.net/hamadahamud/types-of-motors-ppt
 https://www.iqsdirectory.com/articles/electric-motor/ac-motor.html?
fbclid=IwAR3Vr63MRUYYAs7t9LtlNSo602JzDIMuAoyKNqK_NDMhDPD_370L1ciF_t
k
 https://www.energy.gov/sites/prod/files/2013/10/f3/omguide_complete.pdf?
fbclid=IwAR2iPO1uHpy2qcdMaNM5mQSR8Hz1pmJocVjTPr1DeKzA1ff9iAOxbVTSy
HI

EE400 – EE41S1– S. Y. 2022-2023 MG1 50