1st FUOYE INTERNATIONAL ENGINEERING CONFERENCE
Ogunlari and Nasir, 2018
DESIGN AND FEASIBILITY ANALYSIS OF A SELF-INDUCTION MOTOR-
GENERATOR SYSTEM
O. Ogunlari andA. Nasir
Mechanical Engineering Department, Federal University of Technology, Minna
PMB 65, Niger State. Nigeria
ABSTRACT
Globally, as the demand for energy increases, more ways and techniques of generating
energy are being developed. This research provides the analysis of system design to affirm
the possibility of a free, clean and sustainable energy generator that comprises of a
generator coil, electric motor, flywheel and bicycle frame as the major components and the
setup is arranged such that it is self-inducting. A 3kW generator coil and a 1HP electric
motor of 1440rpm rotational speed were connected side by side to a 20kg flywheel which
was driven by a bicycle cyclist at a rotational of 95rpm for initial excitation before the
electric motor is plugged in to the output of the generator and so the system continues. By
varying the pulley sizes, the rotational speed of the generator is 3120rpm. The setup is
proven to be achievable with its usable output power calculated to be 2.25kW.
Keywords: Generator;Electric Motor;Flywheel;Power; Torque; Transmission
1. INTRODUCTION
According to Nikola Tesla, everyone should be able to access free energy sources that they will
require to power and meet their daily activities. Free energy generates electrical power that can
drive equipment and they do not require non-renewable sources of fuel such as coal, gas or
oil.(Jibhakateet al., 2017) Free energy refers to a method of generating power without fuel
combustion from the environment. Furthermore, free energy can be generated through the
following methods; Battery-Charging Pulsed Systems, Moving Pulsed Systems, Energy-
Tapping Pulsed Systems, Aerial Systems and Electrostatic Generators, Motionless Pulsed
Systems, Fuel-less Motors, Magnet Power, passive Systems and Gravity Powered
Systems(Maji, et al., 2016).Solar energy in solar cell or the mechanical energy which drives
windmill which is then transforms into DC current and other energies are obtained from wind
power, water power and telluric power. Development of Free energy generator is a positive way
forward into generating free energy. These sources of electric power from Wind, Solar, Tidal,
Geothermal, and Hydroelectric are only free after the capital cost of starting up these methods
for generating electrical power(Kharwade, et al., 2017).
From History, Human power has been used to power devices. The first human powered device
recorded to give a rotary motion is the potter’s wheel around 3,500 B.C.E. subsequently, other
devices such as the Archimedes screw which was used to transfer water from one level to
another. The use of hand cranks were introduced by the Chinese after 200 C.E in the textile
industry, metallurgy and agriculture. The technology of incorporating flywheel in devices to aid
smooth motion such as in the spinning wheel gained popularity in the mid-15th century in
Europe. Pedal power and Cranks became one of the most devices to couple human power to
applications and in the 19th century, the use of bicycle pedal with the electric dynamo for self-
transportation and to generate electric power(Mankodi, 2012).
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Design And Feasibility Analysis Of A Self-Inducting Motor-Generator System
The use of flywheel for energy storage can be dated to 1973 when Dr Richard Post proposed the
construction of a 200-tonne, 10 megawatt-hour flywheels for electricity storage for the United
States power grid. The material used for the flywheel were of composite materials thus making
it difficult to achieve dynamic stability and structural integrity made difficult with high cost
production. Technology has improved and other electricity storage devices have been made
such as; fuel cells, pumped hydro, compressed air energy storage (CAES), ultra-capacitors also
referred to as super capacitors batteries, super-conducting magnetic energy (SMES) and
flywheel(Fiske & Ricci, 2006). Flywheel is a storage device which stores mechanically
generated energy in the flywheel and the energy stored is then converted to drive a device
which most times produce electrical power or to stabilize the electricity produced. With lower
energy densities compared to batteries but the density is sufficient to meet the requirements for
many high power applications and still give better performance than batteries (Tsao, 2003).
Many methods have been proposed to alleviate these problems, but a fundamental limitation
remains in all present designs – the rotating mass is far from the axle while the stabilization
system (bearings and actuators) operates directly on the axle. If the harbour or spokes are
flexible enough to expand as rpm increases, then the stabilization system must transmit control
forces to the rim through a “floppy” structure – an impossible task – but if the structure is rigid
it will delaminate under high radial stress. The only way to resolve this conflict, so far, has been
to restrict composite flywheels to small diameters (Fiske & Ricci, 2006).
Energy stored in a flywheel is based on the rotating mass principle which is stored in the device
as rotational kinetic energy and the source of its input energy is usually electrical (Amiryar &
Pullen, 2017).
1.1 Chas Campbell Motor-Generator System
Chas Campbell discovered a self-powering generator system through a 750 watt capacity
electric motor (1HP) that is connected to a series of pulleys using belt drives which form a gear-
train such that the rotational speed achieved at the shaft of the generator is over twice that of the
electric motor. The intriguing thing is the electrical power that is generated at the generator
output for this system is greater than the input power from the electric motor (Kelly, 2009).
Campbell demonstrated this generator in Australia to prove that flywheel electric system is
capable of generating power gain higher from the source which has resulted in a system that can
power extra loads (Maji, et al., 2016).
In October 2009, Lawrence Tseung proposed a gravitational theory to explain that if an energy
pulse is applied to a flywheel, then during the instant of that pulse, excess energy equal to 2mgr
is fed into the flywheel where m is the mass of the flywheel, g is the gravitational constant and r
is the radius from the centre of mass of the flywheel that is, the distance from the axle to the
point at which the weight of the wheel acts (Kelly, 2009). There had also been a larger structure
of the generator by Jim Watson which had generated additional KW of output power resulting
from the large size of the flywheel and other components. Therefore, there are two main factors
to consider for the design of this system. First, are the size, weight and rotational speed of the
flywheel while secondly, is the effectiveness of the power transmission system between the
motor, flywheel and generator (Maji, et al., 2016). In 1998, Jacob Byzehr lodged a patent
application for a design of the type of Chas Campbell’s. Jacob however, carried out a critical
analysis on the operation of the system and came up with the following conclusions about the
key design factors. He stated that a key feature in order to attain high performance with a
system of this kind the careful analysis of the diameter ratio of the driving and take-off pulleys
on the shaft containing the flywheel since the flywheel will be rotating at high speed. The
driving pulley from the flywheel needs to be three to four times larger than the power take-off
pulley.
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Ogunlari, et al.
Figure 1:Chas Campbell Motor-Generator System (Jibhakate, et al., 2017)
Figure 2: Jacob Byzehr Motor-Generator System (Kelly, 2009)
As shown in figure 2, Jacob used Chas 1430rpm motor and the readily available 1500rpm AC
generator and the pulley ratio 4:3 step-up from the electric motor to the shaft of the flywheel
gives a satisfactory flywheel speed while providing a 3.27 ratio between the 9-inch diameter
driving pulley and the 2.75-inch diameter power take-off pulley. Furthermore, he concluded
that if a generator which has been designed for wind-generator use and which has its peak
power output at 600rpm is used, then an even better pulley diameter ratio can be achieved
(Kelly, 2009).
2. METHODS
The design setup for the motor-generator system is as shown in Figure 3.the arrangement
consists of a Bicycle frame connected to drive flywheel, 3kW DC generator coil winding, 1HP
electric motor, pulleys for speed variation, Ø30mm shaft and belt drive for torque transmission.
2.2 Design Calculations
2.2.1 Belt selection
For Pulleys 1 and 2
Diameter of Driver Pulley from Motor, d1 = 60 mm
Diameter of Driven pulley of Flywheel, d2 = 60 mm
“A” type of V-belt was selected according to power transmission which has,
Pitch Width = 11 mm
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Design And Feasibility Analysis Of A Self-Inducting Motor-Generator System
Nominal Pitch Width = 13 mm
Nominal Height = 8 mm
For Pulleys 3 and 4,
Diameter of Driver Pulley from Flywheel, d4 = 130 mm
Diameter of Driven pulley of DC generator, d5 = 60 mm
Centre distance between pulleys C3 = 456.82mm
Figure 3: Setup Design Arrangement
2.2.2 Bicycle Frame Design Calculation
BICYCLE
Average Cyclist speed = 85rpm
Number of teeth on the sprocket = 44
Number of teeth on the freewheel = 20
44
ℎ =
20
= 2.2
ℎ ℎ = 85 × 2.2
= 187
500
ℎ = = 8.33
60
ℎ = 187 × 8.33
= 1558.33
The synchronous speed of the DC generator is 1500 rpm. For the generator to generate power,
the rotational speed must be higher than the synchronous speed. Hence, 1552rpm is sufficient to
generate power from the generator.
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2.2.3 Power Transmission
Electric Motor
Power of Electric motor (Pe) = 1HP = 0.75kW
Speed of Motor N1 = 1440 rpm
Diameter Driven Pulley D1 = 60mm = 0.06m
Flywheel
Mass of Flywheel Mf = 20kg
Diameter of Flywheel Df = 400mm = 0.4m
Diameter of Driver Pulley D2 = 60mm = 0.06m
Diameter of Driven Pulley D3 = 80mm = 0.13m
Speed of the Flywheel
N D
=
N D
D ×N
N =
D
0.06 × 1440
N = = 1440rpm
0.06
Angular speed of the flywheel
2× ×N
ω =
60
2× × 1440
ω =
60
ω = 150.816 rad/s
Moment of inertia of the flywheel
I = KM r
Where,
K = Inertia Constant = 0.606 for circular disk
Therefore,
I = 0.606 × 20 × (0.2)
I = 0.485 kgm2
Maximum Kinetic Energy that can be stored in the flywheel
1
K. E = Iω
2
1
K. E = 0.485 × 150.816
2
K. E = 5515.775 Nm
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Design And Feasibility Analysis Of A Self-Inducting Motor-Generator System
Generator
Output power of the DC generator (Pg)= 3kW
Frequency = 50Hz
120 ×
=
120 × 50
= =4
1500
Transmitted Speed of rotation from the flywheel to the generator (N3)
N D
=
N D
0.08 × 1440
N = = 1920 rpm
0.06
This speed is calculated without considering losses hence, in actual situation is will be lower to
sufficiently meet the required rotational speed for the generator which is 1500rpm
Angular speed of the generator
2× ×N
ω =
60
2× × 1500
ω =
60
ω = 157.1.2 rad/s
3. RESULTS AND DISCUSSION
Maximum Torque from the electric motor
P
T =
ω
750
T =
150.816
T = 4.973 Nm
Maximum Torque required by the generator
P
T =
ω
3000
T =
157.1
T = 19.096 Nm
the torque generated from the electric motor is not sufficient to that required by the generator,
hence the inclusion of the 20kg flywheel that has a kinetic energy of 5515.755Nm which is
added to the torque from the electric motor to overcome the induced magnetic field from the
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generator at a speed of 1500rpm which was achieved by varying the sizes of the pulley from the
flywheel to that of the generator.The cyclist speed transmitted to the generator from the bicycle
is 1558.33 rpm. At this speed of the generator, the power generated will power the electric
motor by attaching a capacitor to the motor before plugging it to the output of the generator.The
expected overall power output is determined by the capacity of the generator which in this case
is 3kW of electrical power.The usable electrical is therefore what is left after the electric motor
has been plugged to the generator.
Usuable Power = output power − motor power
= 3kW − 0.75kW
= 2.25kW
4. CONCLUSION
From the review of existing designs and the modification made to them to birth this design,
also with the calculated results, the feasibility of this setup to generate electrical power and
remain self-inducting has been analyzed to give a usable power even after powering the electric
motor.
6. REFERENCES
Amiryar, M. E., & Pullen, K. R. (2017). applied sciences A Review of Flywheel Energy
Storage System Technologies and Their Applications. MDPI Applied Sciences, 7(286), 1–
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Fiske, O. J., & Ricci, M. R. (2006). Third Generation Flywheels For High Power Electricity
Storage. California, USA.
Jibhakate, B. M., Karemore, J., Jaiswal, D., Kalambe, K. V., Zade, N. S., & Sonakalihari, S. .
(2017). Review of Free Energy Generator using Flywheel. International Research Journal
of Engineering and Technology, 4(2), 2021–2023.
Kelly, P. (2009). Chapter 4: Gravity-Powered Systems Author: In A Practical Guide to Free-
Energy Devices (pp. 4-1-4–60).
Kharwade, A. U., Meshram, S. D., Karemore, J. P., & Jibhkate, B. M. (2017). Review of Free
Energy Generator using Flywheel. International Journal of Recent Trends in Engineering
and Research, 3(3), 90–96.
Maji, S. U., Mane, M. ., Kshirsagar, C., Jagdale, A., & Malgar, D. (2016). Conventional Free
Energy using Flywheel. International Journal for Scientific Research and Development,
4(2), 1259–1265.
Mankodi, H. (2012). Analysis of a Treadmill Based Human Power Electricity Generator.
University of Minnesota, Twin Cities.
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