Department of Electrical and Electronic Engineering
Project Assignment
Course Code: EEE234.4
Course Title: Energy Conversation laboratory
Project Number: 01
Project Title: Using Star-Data And Phase Shifting In Indication Motors
Submitted To: Ummay Honey (Lecturer)
Department of Electrical and Electronic Engineering
Southeast University
Submitted By
Sl No
Name
Id
01
Md Nurjamal
2023200520160
02
Abu Talha Rakib
2023200520161
03
Suborna Akter
2023200520162
Batch:15
Section:A
Date of Submission:05th June 2025
Project Title: Using Star-Delta and Phase Shifting in Induction Motors
2. Theory:
Induction Motors:
Three-phase induction motors are widely used in industrial applications due to their robustness, low cost, and
minimal maintenance. However, they draw very high inrush current during startup, which can damage
equipment and affect power quality.
Star-Delta Starting:
Star-Delta starting is a method to reduce starting current in three-phase motors. Initially, the motor windings are
connected in a star configuration to limit the voltage across each phase, reducing the starting current to onethird. After a short time, the connection switches to delta, allowing full voltage and normal operation.
Phase Shifting:
Phase shifting in induction motors refers to adjusting the phase angle between current and voltage, often to
control the motor's direction or to balance phases in multi-motor systems. This can be done using phaseshifting transformers or electronic controllers.
3. Components Used in Multisim:
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Three-Phase Induction Motor (symbolic/functional block)
Star-Delta Starter Circuit (manual or timer-based)
Contactors (K1, K2, K3)
Timer Relay
Push Buttons (Start/Stop)
Phase-Shifting Transformer (or adjustable AC sources for simulation)
Ammeter and Voltmeter
Power Supply (Three-phase)
Resistors (for load simulation)
Ground and Wires
4. Simulation Steps:
1. Design the Star-Delta Starter Circuit:
o Connect the motor in star configuration using three contactors (main, star, delta).
o Set up a timer relay to switch from star to delta after a few seconds.
2. Configure Power Supply:
o Apply three-phase AC supply to the system.
3. Insert Measuring Instruments:
o Add voltmeters and ammeters to measure current and voltage during start and run phases.
4. Simulate Phase Shifting:
o Adjust phase angles using phase-shifting transformers or AC source phase settings.
o Observe motor behavior and direction of rotation.
5. Run Simulation:
o Press the start button and observe the current draw during the star and delta phases.
o Note any changes in motor direction or phase behavior during phase shift.
5. Data Table:
Parameter
Star Mode
Delta Mode
With Phase Shift
Line Voltage (V)
400
400
400
Phase Voltage (V)
230
400
400
Line Current (A)
5.2
15.6
14.8
Motor Speed (RPM)
Direction of Rotation
900
CW
1450
CW
1450
CCW (if shifted)
(Values are indicative; replace with simulation results)
6. Results:
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The simulation successfully demonstrated reduced current during the star-starting phase.
After switching to delta, the motor operated at full speed and power.
Phase shifting successfully changed the direction of the motor and affected load balancing.
7. Calculations:
Line to Phase Voltage:
Vph=3Vline=1.732/400V≈230V
Current Reduction (Star Mode):
Istart=13×Idelta≈0.58×IdeltaI_{start} = \frac{1}{\sqrt{3}} \times I_{delta} \approx 0.58 \times
I_{delta}
Starting Torque:
T_{start} = (I_{start})^2 \propto \text{~33% of full torque}
Add additional values from the simulation for more precise calculations.
8. Discussion:
The project demonstrates how Star-Delta starting significantly reduces the inrush current in induction
motors, which helps protect equipment and improves system stability. This method is simple and
widely used in industry.
Phase shifting is more advanced and can be used for:
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Changing the direction of rotation
Synchronizing multiple motors
Power factor correction
While not as commonly discussed as Star-Delta starting, phase shifting is vital in complex motor
control systems.
The Multisim simulation validates the theoretical expectations, showing current drops and correct
switching behavior.
9. Conclusion:
The combination of Star-Delta starting and Phase Shifting techniques provides efficient and reliable
control of three-phase induction motors. Star-Delta starting is effective in limiting startup current and
mechanical stress, while phase shifting allows directional control and power quality improvement.
These methods are essential in real-world industrial motor control applications.