“Electrical drives” are electrical power systems used to control

motion.

For motion control, it involves a complex electronic system or a

combination of different systems.

Block Diagram of electrical Drive

Parts of Electrical Drive

Major parts of electrical drives are

 Power Modulator
 Control Unit
 Sensing Unit

Power Modulator

The power modulator converts the motor’s power to meet the motor’s
needs. The power modulator will convert DC to AC if the source is DC
and the induction motor is used. It also chooses whether the motor
should operate in motoring or braking mode. It also controls the output
power of the source as well as the power flowing from the source to
the motor

Control Unit

The control unit’s main function is to keep the power modulator

running at low voltage and power levels. As needed, it also has a
power modulator. It also generates commands for the power
modulator and motor’s protection. From one input to the control unit,
an input command signal adjusts the operating point of the drive.

Sensing Unit

It understands certain drive parameters such as motor current and

speed. This is mainly required for protection or closed-loop operation.
Types of Electrical Drives

Electrical drives are classified into various types based on the

following parameters. They are

 Based on Power Supply

 Based on the number of motors
 Based on Speed
 Based on Control Parameters

Based on Power Supply

Based on power supply, drives are classified into two. They are

 A.C Motor Drives

 D.C Motor Drives

A.C. Motor Drives

An AC drive is a device that changes the frequency of the power

supply to an electric motor, such as a three-phase induction motor, to
control its speed.

A.C motor drive is also called variable frequency drive (VFD) or

variable speed drive.

DC Motor drives

It is essentially the speed control system of a direct current electric

motor that supplies voltage to the motor in order for it to operate at the
required speed.

Analog DC drives and digital DC drives are the two types of DC

drives.

Based on Number of Motors

Based on the number of motors, electrical drives are classified into

three. They are
Individual Motor

Individual motor, will have a separate drive motor for different parts of
a machine.

For Example Lathe machine.

Multi-Motor

In Multi motor, special motors are provided to operate the various

parts of a machine.

Example: Cranes.

Group Drive

A single shaft connects the motor to other machines, which are

connected to the shaft by belts and bolts. In this case, a single motor
acts as a power source for two or more machines

Group drive is the cheapest among these.

Based on Speed

There are two types available in this category. They are

Constant Speed drive

More or less constant speed drives, squirrel cage induction motors,

and manual controls are used in machine tools.

Variable Speed drive

Variable speed drives are used to control machine speed,

acceleration, deceleration, torque, and, finally, machine direction.

It is used to cut down or reduce energy consumption.

Based on Control Parameters

There are three types available in this category. They are

Vector Control Drive

Vector control is more accurate than any other type of variable

frequency drive (VFD).

In this control mode, torque and speed are controlled using the pulse
width modulation (PWM) techniques in the inverter.

They are used for AC synchronous and induction motors.

Constant Power Drive

A constant power drive at that speed limit is when a motor’s armature

carries a rated current and delivers constant power over a specific
range of control.

Constant Torque Drive

Constant torque load type drive is characteristic when handling fixed

volumes.

Examples: screw compressors, conveyors, and feeders.

Application of Electric Drive

 This drive’s primary application is electric traction, which is the

transportation of materials from one location to another.
 It is used in transportation systems, paper machines, textile mills,
machine tools, fans, pumps, robots, and washing machines.

Advantages of Electrical Drive

The advantages of electrical drives are

 It has a very large range of torque, speed, and power.

 Their work is independent of the environmental condition.
 Pollution free
 Easy to start and it does not require any refueling.
 High efficiency

Disadvantages

 Higher initial cost

 High maintenance
 High attention required
 The power breakdown totally stops the entire system
Utilization of electrical energy

Illumination

Solid angle
Polar curves
Ruby laser
illuminous
Illumination
intensity
illuminous
efficency
MSCP
Law of
illumination
Flurocent Flicer effect
tube Storsobic effect
Sodium
vapour lamp
Flurocent
lamp
Neon lamp
Halogen lamp

Incansant
lamp
Mercury
lamp
CFL
LED
Lighting
system
Street
lighting
Factory
lighting
Flood lighting
Method of
calculation of
light
reflectrors
glare
Electrical welding

Resistance Spot welding

welding Seam welding
Projection welding
butt welding

Arc welding
TIG welding
MIG welding
ultrasonic
welding
Carbon arc
welding

Electrical heating

Electric kettle
Electric iron
Electric furnance 1.resistance
2.arc
(a)DC
(b)ac
3.induction

Heating element
Resistance heating
induction heating
dielectric heating
Batteries

Cell
Battery
Primary cell
Secondary cell
Dry cell
Lead-acid
battery
Ni -cd
Ni -iron
electroplating
Faraday law of
electrolysis

Electric traction

Adhension coefficent

Tractive force
pantagraph
Electric drives

Load Elevator
Lift
Crane and hoist

modulator
motors
Sensing device
Control unit
Belt drive
Group drive
Rope drive
Classification of duty
Types of load Elevator
crane
Hoist
blower

Earthing and wiring

plate earthing Best earth

Copper 60cm*60cm*3.18mm
Galvanized iron(GI) 60cm*60cm*6.35mm
Pipe earthing

Rod earthing cheapest

Strip or wire earthing Transmission line

Earth wire Green

Minimum as possible
Power station 1 ohm
Maximum at all 8 ohm
 IE rule 800 W 10 point

3 plug pin

2 plug pin

switch SPST
DPST

SWG Standard wire guage

AWG American wire guage

Neutral grounding Resistance

Reactance
Solid
ARC/Peterson coil
Voltage variation IE RULE +-

Frequency variation

symbol Electrical diagram

Energy meter

LA

Circuit analysis
Electrical material

Electronic circuit and devices

Electric machine

Basic principle of
rotating machine
Fleming right hand
rule
Fleming left hand rule
Dc generator emf
Dc motor
BLDC
2 point strarter
3 point starter
4 point strarter
Inter pole
Compensating winding
Pole shoe
Armature core
Shaded pole motor
Hytersis motor
Repulsion motor
Reluctance motor

Stepper motor Variable reluctance Stepper motor

(a)single stack Variable reluctance Stepper
motor
 (b)muti stack Variable reluctance Stepper motor

Permanent magnet Stepper motor

Hybrid Stepper motor

Servomotor
1. Ac (a)positional rotation servomotor
servomotor

(b)continuous rotation servomotor

(c)linaer servomotor

2.dc servo (a)series motor

motor

(b)split series motor

(c)shunt control motor

(d)permanent magnet shunt motor

 Repulsion (a)compensated Repulsion motor
motor

(b) Repulsion start induction run motor

(c) Repulsion induction motor

Power system

Economy of power system

cost (i) Fixed cost. It is the cost which is independent of maximum demand and
units generated. The fixed cost is due to the annual cost of central
organisation, interest on capital cost of land and salaries of high officials.
The annual expenditure on the central organisation and salaries of high
officials is fixed since it has to be met whether the plant has high or low
maximum demand or it generates less or more units. Further, the capital
investment on the land is fixed and hence the amount of interest is also
fixed.
(ii) Semi-fixed cost. It is the cost which depends upon maximum demand but is
independent of units generated. The semi-fixed cost is directly proportional
to the maximum demand on power station and is on account of annual
interest and depreciation on capital investment of building and equipment,
taxes, salaries of management and clerical staff. The maximum demand on
the power station determines its size and cost of installation. The greater
the maximum demand on a power station, the greater is its size and cost of
installation. Further, the taxes and clerical staff depend upon the size of the
plant and hence upon maximum demand.
(iii) Running cost. It is the cost which depends only upon the number of units
generated. The running cost is on account of annual cost of fuel, lubricating
oil, maintenance, repairs and salaries of operating staff. Since these charges
depend upon the energy output, the running cost is directly proportional to
the number of units generated by the station. In other words, if the power
station generates more units, it will have higher running cost and vice-versa.

Classification
 (a)fixed cost
(b)semi fixed cost
(c)operating cost/running cost

Mass curve

Load curve Maximum demand

Average load

Connected
load

Maximum
demand

Demand Maximum demand/connected load

factor
Average load

interest The cost of use of money is known as interest.

depreciation 1. Depreciation. The decrease in the value of the power plant equipment and

building due to constant use is known as depreciation.

The following are the commonly used methods for determining the annual

depreciation charge :

(i) Straight line method ;

(ii) Diminishing value method ;

(iii) Sinking fund method.

Load factor Average demand /maximum demand

Diversity Sum of individual maximum demand / maximum demand on the power station
factor

Plant Average demand/plant capacity

capacity
factor

Plant use
factor
Utilization
factor

Reserve RC=Plant capacity- maximum demand

capacity

Spinning
reserve

Hot reserve

Cold reserve

Firm power
 Kelvin law

Classification of tariffs

Simple tariff

Flat demand tariff

Block rate tariff

Flat rate tariff

Block rate tariff

Two part tariff

Three part tariff

 Power factor tariff

Maximum demand
tariff

Peak tariff

Switchgear and protection

Fuse

Classification of 1.Kit kat fuse

fuse
2.HRC fuse

3.DC fuse

4.cartridge

Circuit breaker

Vaccum Circuit
breaker

Air break Circuit

breaker
Air blast Circuit
breaker

Oil Circuit
breaker

isolator

relay

Distance 1.reactance relay

2.impedance relay

3.mho relay/

differential
 overcurrent

IDMT

Merz-price
protection

Substation
Lighting arestor

Bus bar

Wave trap

batteries

earthing

switchyard

CVT

Ground wire
Electromagnetism

Energy

electron Mass of electron

nucleous

Electric charge

Charge
conservation

Charge density

Coloumbs law

Fleming left hand

rule

Fleming right hand

rule
Electric force

Electrical field
strength

Electric
displacement field

Electric flux

electric
susceptibility

Gauss law

Electric potential volt

Equipotential
surface

Electric current

resistance
conductance siemens

resistivity

Electric power

conductivity

Electric Current
density

capacitance farad

permittivity

Dielectric strength

polarizability
Polarizability of the molecule is defined as the electric
dipole moment induced in the molecule per unit incident
 electric field.
Polarizability α=P/E
Units -

Dielectric
constant/relative
permittivity

Dissipation factor

Types of
polarization

Electric dipole Unit -debye

moment

Clausius-
Mossotti
equation

Faraday law

Lenz law

polarization
Magnetic flux weber

Magnetic field(B) tesla

Magnetic field
lines

Magnetic field
intensity(H)

Magnetic force

inductance

self inductance

mutual
inductance

permeability
 Magnetic
susceptibility

Magnetic dipole

Magnetic dipole
moment

mmf Gilbert

reluctance

permeance

BH curve

corercivity

retentivity
Hysteresis loss

Eddy current loss

Magnetic material

Hard magnetic
mateial

Soft magnetic
material

Types of
magnetic material
1.diamagnetic
material

2.paramagnetic Curie law

material

3.ferromagnetic Curie wesis law

material

4.ferriamgnetic
magnetic
5.antiferrimagneti Neel tempreture
c material

ferrites

Biot- savart law

Ampere law
Lorentz force

Maxwell equation

Continuity
equation

Poisson equation

Laplace eqaution

electromagnetic
spectrum

Em wave Frequency
Wavelength
Amplitude
velocity
period
Measurement and instrument

Miscellaneous Instruments

Lux meter

hygrometer

pyranometer

Megger Earth
Tester

Power factor meter

Weston synchroscope

Q-meter

potentiometer

Analog recorder
Digital recorder

Spectrum analyzer

Distortion analyzer

Electric conductro Copper aluminium silver gold

Super conductor
Dielectric material mica
insulator Paper glass porcelin
Heating element nichrome
semiconductor Silicon germanium
Magnetic material Iron cobalt nickal

principle
Construction Stator rotor
load
Starting current
Starting torque
Maximum torque
Running torque
Charatertics
Braking of motor
Direction of motor reversed by
Speed control method
application
electric year invention
bulb
Ac motor
thyristor

LED
TV
radio
transistor
computer

Types of Electrical Loads