It includes the characteristic of induction motor and its power equations of power flow diagram. Later on, it includes the

2. Group Members:
• Asad Tanvir (12EL13)
• Uzair Nazir (12EL35 )
• Wasif Hussain (12EL36)
• Azfar Rasool (12EL04)
• Mosa Ali (12EL37)

3. Introduction of Topics:
• Power Equations
• Effect of changes in shaft load
• Effect of changes in field excitations

4. Power Equation
• What is Power Equations 

5. Simply!
Prepare for complex thing.. 

6. Power Equations in Induction Motor
• Electric Circuit of Induction Motor

7. Power Equations in Induction Motor
Derivations

8. Power Flow Diagram

9. Easy  or Tough  Numerical Problem
A 460-V, 25-hp, 60 Hz, 4 pole, Y-connected motor with the power
factor of 33.6 lagging has the stator copper losses of 685W. It has
following impedances:
R1=0.641 R2=0.322
X1=1.106 X2=0.464
Xm=26.3
The slip of the induction motor is 0.2% and it drives the load current of
18.88A. Assuming core and frictional losses are negligible. Find the
power converted or electromechanical power generated?

10. Effect of load
changes of
synchronous motor

11. If load is attached to the shaft of
synchronous motor the will develop
enough torque to keep the motor
and its load turning at synchronous
speed

12. What happens when load is
changed on synchronous motor


13. If load on the shaft on the
motor is increased
• The rotor will initially slow down
• As it does ,the torque angle alpha becomes
larger and induced torque increased
• The increase in induced torque eventually
speed up , and the motor gain turns at
synchronous speed

15. (b) Assume that the shaft load is
now increased to 30 hp. Sketch the
behavior of the
phasor diagram in response to this
change

16. (b) As the power on the shaft is
increased to 30 hp, the shaft slows
momentarily, and
the internal generated voltage EA
swings out to a larger angle /j while
maintaining
a constant magnitude. The resulting
phasor diagram is shown in Figure 6-
7b.

18. Following phenomenon will occurs 
Rotor speed decrease
Slip increase
Smaller amount of induced
voltage is developed
Power factor will improve
Torque will increase

19. Variable Load Change :
• Under extreme load changes, e.g. frequent starts /
stops, or high inertial loads, this method of calculating
the motor rating is unsuitable since it would
underestimate the heating that would occur.

20. Effect of changes field
excitation
•Increases excitation
•Decreases excitation

21. • Power factor will improve and adjusted
• Pull out torque will increase
• No slipping of poles
• Leading power factor will occur

22. “Those who knee down to Allah can stand up any
thing.”

23. Thank You!

24. Any Questions?