International Journal of
Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-5, Issue-5)
Research Article
May
2016
Special Issue on International Conference on Advances in Engineering (ICAE) -2016
Conference Held at Hotel Magaji Orchid, Sheshadripuram, Bengaluru, India.
Squirrel Cage Induction Motor as a Synchronous Motor
Indhudar.D.P., S.Tejaswi, Praveena Anaji (Asst. Professor)
EEE Department, Jain institute of technology,
Davangere, India
Abstract: Motor is a device which converts an Electrical energy into mechanical energy. AC Motor Classified is an
induction and synchronous motors. Induction motors starting torque is high for this reason most of the industries and
other automation systems adopting these motors. Controlling the speed of the IM is bit complicated to compare with
other motors. Inrush current is nearly 8-10times of the full load current it may damages the motor. To avoid and over
come from this demerit of motor now we are using different type of starters those areDOL, STAR-DELTA,
AUTOTRANSFORMER, ROTOR-RESISTANCE (for slip-ring motor) starter. This starter will control inrush current
while starting the motor to improve the starting method and keeping the motor at constant level of speed in different
load condition approximately ±10% of locked speed or reference speed.
Key words: IM, Smooth Starting, Speed Constant.
I. INTRODUCTION
Now commonly all the industries are using DC motors such as compound motors and shunt motors because of its
high efficiency and some industries like paper mills cotton mills need constant speed drives. All AC motors are variable
speed drives the speed of the AC drives will changes with respect to the load variations and power variations. DC drives
also changes its speed with respect to load but its comparatively lesser then the AC drives. DC drives need one DC
Source to run the motor for this reason we need one external circuit to convert the AC source into DC. This circuit having
a no semiconductor devices such as diodes and thyristors these are having more cost for higher ratings and these
circuitsneed proper filters to reduce the pulsating AC or ripple content of AC in the pure DC for that reason we need one
regulator to convert the pure AC. The presence of AC in the DC is produces a harmonics in the system and this may
effect the motor efficiency. Apart from these things DC drives are have a more size comparatively same rating of AC
motors and cost of the motor will also increases because DC.Motors construction is complicated compare to AC.To
overcome from these limitations a new method is adopting by using microcontroller unit. In this method using power
electronics component such as TRIAC as used for power controlling device by using closed loop controlling system
speed of the motor will sense by the tachometer which constructed by using micro controller 89C0251/52and by using
this speed in the form pluses and send to ATMEGA32/16 micro controller. This micro controller is programmed as to
show the details of actual speed and reference speed and over current and send the signal to opto-coupler MOC3022 this
opto-coupler is controller the firing angle of TRIAC and it works inversely proportional to the speed of the motor when
speed increases firing angle will be reduced and adjust the speed of the motor and this operation will runs continuously
when the signal passes the zero reference line. Zero crossing detector is used to send the signal to ATMEGA32/16
frequently to run the program we are using a one 555timer to create a pluses and amplifier to use as NPN transistor keys
to control and switching purposes to provide a supply to required equipment’s we using one step-down center tapped
transformer with full wave rectifier and regulator as 7805 for microcontroller, 555timer, MOC3022,LCD and zener diode
for ZCD.
II. PROBLEMS IN MOTOR CONTROL
1.
2.
3.
Starting of motor
Overload protection
Stopping of motor
1. Starting ofmotor:
Starting speed of motor for is more When starting a squirrel cage motor there will always be a starting current
(Ist) whichis higher than the rated motor current.When starting DOL this starting current istypically 7-8 times the nominal
current and When using statically controlled device it will reduced to3-5 times the nominal current.
Depending on the application, the startcan be short or long. Since the current ishigher during the starting. It is very
important to select a softstartingwiththyristorsand heat sink dimensioned for the motorand the start performed.
2. Load control and protection:
Load is gradually increases in a while running motor then the motor will decreases its speed and the current will
increases gradually with respect to load. It may cause the burning of windings and more heat will produce in the derives
it may cause the losses like eddy current sand hysteresis due to over flux in the windings it will reduces the efficiency of
drives.
© 2016, IJERMT All Rights Reserved
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Indhudar et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-5, Issue-5)
3. Stopping of motor:
While stopping the motor speed of the motor will decrease suddenly this may cause the breakdown of connected
drives and all and also cause the bending of shaft. In certain applications cause the damage the operator and overall
unit.For that purpose adopting a static control system it will control the speed gradually and without affecting other
particulars.
III. BLOCK AND CIRCUIT DIAGRAM
Figure 1: block diagram
IV. DESCRIPTION
Block-diagram represents the actual concepts of proposed work here we using mainly controlling part as a MCU
to receive the feedback from motor and send the control to SCU and we are providing the keys to adjust the reference
speed (increases and decrees) RPM sensor as a tacho- generator it send the speed in terms of pluses to MCU. The power
supply block is used to provide a supply to micro controller unit and all low voltage controlling devices such as zero
crossing detector and display device (LCD) pulse generator and opto-coupler and photo sensors.
V. CONSTRUCTION & PRINCIPLE OF OPERATION
Main Particulars in circuit:In proposed work we have mainly divided into four divisions those are
1. power supply unit
2. Tacho- Generator & ZCD
3. MUC (micro controller unit)
4. SCU (static control unit)
5. Display (LCD)
1) Power Supply Unit:
This unit is providing the supply to all the required components such as IC’s,display(LCD),pulse generator and
amplifiers. These particulars are operated in 5v DC for that reason we convert the supply to 5v DC. Using center taped
step-down transformer (12-0-12) and full wave rectifier by using Diode (1N4007) this gives a 12volts DC with pulsating
AC for that reason we need to convert pure DC we adopting RC filter to remove the pulsating content. then the output
will be nearly 10.7-11 volts due to voltage drops we need 5vDC so we are using voltage regulator as a 7805 it gives a
constant 5v DC without distortion and also we are using zener diode as 5V regulator in ZCD.
2) Tacho-Generator and ZCD:
Tacho-generator is device which is used sense the speed in terms of RPM and this speed is in the form of
(rotational) analog commonly used tacho meters will sense the speed in the form of RPM and converted into digital form
directly send to display or data storage system but in this proposed paper we need closed loop system so we need the
speed as the feedback signal and in terms of voltage or pluses because the microcontroller accepts in that pattern so we
create the one tacho-generators by using light and photo sensors (LDR, Photo diode) and timer 555. Then the light
interrupted signal by blade which is coupled to motor shaft when interrupts the light using that interrupt as an input of
timer 555 it will convert the interrupt into pluses and boost signal by using simple BJT amplifier and feed to MCU. we
using a ZCD to count the signals at particularly when the signal crosses zero crossing line and it enables the
microcontroller to trigger the gate of TRIAC.
3) Display (LCD):
Here we using LCD(2×16) it indicate both the speed and the indicated parameters such as voltage, current etc. 2×16
indicates that the two lines 16 letters in one line in this liquid crystals are used to display so it’s called as LCD.
4) MCU (Micro Controller Unit):
This is the block controlled all the components here we using two micro controllers those are 89C0251/52 &
Atmega32.micro controller 89C0251/52 is used to create the feedback signals which coming from pulse generators. To
maintain the probable control of the speed at constant range we need the sample of speed for that reason we use the photo
sensors such as photo diode LDR to sense the running speed of motor by adjusting the one interrupter to disturb the
optical connection between the light source and the light sensors. When the light sensors are interruptedit will create the
© 2016, IJERMT All Rights Reserved
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Indhudar et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-5, Issue-5)
one pulse. That pulse is given to microcontroller by using this pulse the microcontroller sends the signal to
microcontroller Atmega 32. This will collect the signal from the micro controller 89C0251/52 when sinusoidal wave
cross the reference line at each cycle and compare the speed what we predefined and current speed generate the gate
pulse to control the firing angle of the TRIAC. The complete process will repeated until the motor goes to rest position.
5) SCU (Static Control Unit):
we discuses about how the analog signal is convert and act as a feedback signal by using microcontroller the next
part is that static controller unit. The static controlling unit is the name is because of components used is static devices.
In this unit we are going to control the speed of the motor by using power electronics and electronics devices such as
TRIAC, opto-coupler (MOC3022), resister and capacitors as a snnuber circuit to protect the motor from initialinrush
starting current and torque. Here we using (BT139) TRIAC as a static controlling device it as three terminals M1, M2,
Gate. M1 &M2 are the main terminals 1&2. It’s a bidirectional current controlled device and its configuration is as
connecting of two SCR in anti parallel direction for the these reason it controls the both cycles (+ve& -ve cycles). By
using gate currents we can adjust the firing angel from 0-180°in both the cycles. Here the gate pulse is given to TRIAC is
from microcontroller Atmeg32 through opto-couplers. Above topic we discussed about working of both MCU then
c0llected speed is sensed by the MCU is in the form of pulses then the microcontroller is compare the reference and
present speed and calculate the difference in that and give the command to opto coupler to increase or decrees the firing
angle by varying the light intensity and adjust the present speed to reference speed at different load conditions. The
below figure shows firing angle of the TRIAC with respect to time
Fig2: Firing angle of TRIAC waveform
VI. CIRCUIT
© 2016, IJERMT All Rights Reserved
Page | 30
Indhudar et al., International Journal of Emerging Research in Management &Technology
ISSN: 2278-9359 (Volume-5, Issue-5)
VII. PARTIAL RESULT
Fig1: Input supply wave form
Fig2: Conduction angle control wave form
VIII. CONCLUSION
From the above paper we conclude that the speed of the IM will be controlled and maintain constant by using
proper closed loop system at difference load condition and also protect the system easily.
REFERENCE
[1]
Single Phase Induction Motor Adjustable Speed Control Using DSP and Microcontroller
[2]
A Review on Speed Control Techniques of Single Phase Induction Motor Atul M. Gajare1, Nitin R. Bhasme2
[3]
Microcontroller based
speed control of three phase induction motor using v/f
methodMrs.DeepaliS.Shirke, Prof. Mrs.Haripriya, H.KulkarniElectrical Dept. PES’s Modern College of
Engg. Pune
[4]
Wireless Speed Control of an Induction Motor Using Pwm Technique with GsmP.S.Joshi,
Prof.A.M.JainLecturer,Electrical Department, G.E.S’sR.H.Sapat College of Engg , Management
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Education &Research, Nashik- Maharashtra India
[5]
PI and Fuzzy Based Sensorless Speed Control of Induction Motor K.Bhuvaneshvari1, Mr.G.Mahendran2
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[6]
Speed Control of Single Phase Induction Motor Using AC Chopper by Asymmetrical PWM Method
R.Suneeth1, P.Usha2 PG Student [PE], Department of EEE, DayanandaSagar College of Engineering,
Bangalore, Karnataka, India1 Professor, Department of EEE, DayanandaSagar College of Engineering,
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© 2016, IJERMT All Rights Reserved
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