Download Al-Balqa` Applied University Faculty of Engineering Technology

Al-Balqa' Applied University
Faculty of Engineering Technology
Mechatronics Engineering Department
Electric Drive Laboratory
Experiment Five
Part II
Investigation of three phase Squirrel Cage induction motor Variable
Frequency Drive System
Student’s Name:
Supervisor:
Date:
DI-4000/AC Study Desk
Experiment Objectives:
1- Studying and identifying the workbench components.
2- Investigation of three-phase squirrel cage motor electro-mechanical and torque-speed
regulated characteristics by:
A- Varying stator voltage and frequency (V/f= const).
B- Varying frequency above nominal frequency with fixed stator voltage.
Experiment Procedures:
1-Studying and identifying the workbench components
A- Plot the experiment block-diagram or schematic diagram showing the main components
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B- Write down the specifications and parameters of each component
- Main single-phase power supply: 230 V, 50 Hz.
- Master switch “Main Switch”, magneto-thermal (16 A) and differential (0.03 A) protections.
- Live desk warning lamp (‘Line”).
- Low voltage main control complete with key selector (“ON”), emergency mushroom button with
mechanical lock (“OFF”), warning lamp (“LINE 230 Vac”).
- Reference potentiometer (“INTERNAL SPEED REFERENCE”).
- Motor operation setting switch“DIN” .
- RS 232 interface.
- Two service plugs “SERVICE PLUG”; 230 V, 6 A, 50 Hz.
- Safety bushings (2 mm and 4 mm) for signal check (“TP”).
- Motor brake (“DC MOTOR BRAKE”, 1.5 kW) complete with thermo-switch (10 A) (“BRAKE
POWER”) , warning lamp, thermal cut-off, bridge rectifier and variator:
 Power supply: three-phase, 230 V, 50 Hz
 Rated current, 6.77 A
 Output power , 1.5 kW
 Rotational speed, 1415 rpm
- Three-phase squirrel cage ac motor:
 Power supply: Three-phase, 230 V/50 Hz
 Rated current, 4.9 A
 Output power, 1.1 kW.
 Rotational speed, 1415 rpm
- Digital 4-digits ; frequency, stator voltage, stator current and dc link voltage meter.
2- Investigation of three-phase squirrel cage motor electro-mechanical and torque-speed
regulated characteristics
I- Preliminary steps (Experiment setup):
-
-
Move the master switch (“MAIN SWITCH”) lever downwards.
Move the (“BRAKE POWER”) switch lever downwards.
Set all of the DIN 1, DIN 2, DIN 3, DIN 4, DIN 5 and DIN 6 switches to position “0”( i.e. lever
downwards).
 DIN 1 set to the START/S TOP function.
 DIN 2 set to the REVERSE MOTOR function.
 DIN 3 set to the ALARM RESET function.
 DIN 4, DIN 5 and DIN 6 are not used.
Turn the (“INTERNAL SPEED REFERENCE”) potentiometer knob fully to the left (zero reference).
Set the (“INT/EXT”) switch lever to “INT” position, speed control by (“INTERNAL SPEED
REFERENCE”) potentiometer.
Turn the (“DC MOTOR BRAKE”) variator knob fully to the left (zero reference).
Move the master switch (“MAIN SWITCH”) lever upwards, and then verify that the line lamp will come
ON.
Make sure that the emergency mushroom button (“OFF”) has been released.
Turn the key selector (“ON”) to the right.
Turn the (“INTERNAL SPEED REFERENCE”) potentiometer knob slowly to the right to set the desired
speed level.
Move the (“BRAKE POWER”) switch lever upwards.
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-
Turn the (“DC MOTOR BRAKE”) variator knob slowly to the right to set the desired load torque.
II- For each value of reference frequency under different load torque values fill the following tables:
f ref  50 Hz
TL , %
n, rpm
I1 , A
V1 , V
Vdc , V
f ref  40 Hz
TL , %
n, rpm
I1 , A
V1 , V
Vdc , V
f ref  30 Hz
TL , %
n, rpm
I1 , A
V1 , V
Vdc , V
f ref  20 Hz
TL , %
n, rpm
I1 , A
V1 , V
Vdc , V
f ref  10 Hz
TL , %
n, rpm
I1 , A
V1 , V
Vdc , V
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f ref  60 Hz
TL , %
n, rpm
I1 , A
V1 , V
Vdc , V
f ref  80 Hz
TL , %
n, rpm
I1 , A
V1 , V
Vdc , V
f ref  100 Hz
TL , %
n, rpm
I1 , A
V1 , V
Vdc , V
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III- Plot regulated electro-mechanical characteristics related to natural characteristic and plot regulated
torque- speed (mechanical) characteristics related to natural characteristic.
IV- Results and Conclusions
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