Electric Drives Practice Test 3

1. A 3-phase induction motor runs at almost 70 rpm at no load and 50 rpm at full load when supplied with power from a 50 Hz, 3-phase supply. What is the corresponding speed of the rotor field with respect to the rotor?

2. Armature reaction is demagnetizing in nature due to a purely capacitive load in the synchronous generator.

3. Armature reaction is demagnetizing in nature due to a purely capacitive load in the synchronous generator.

4. If induction motor rotor power is 157.5 KW and gross developed power is 79.9 KW, then rotor ohmic loss will be _________ KW.

5. If induction motor air gap power is 10 KW and mechanically developed power is 8 KW, then rotor ohmic loss will be _________ KW.

6. Calculate the amplitude of the sinusoidal waveform z(t)=.27sin(.369πt+.142π÷4.25).

7. The slope of the V-I curve is 6.9°. Calculate the value of resistance. Assume the relationship between voltage and current is a straight line.

8. Calculate the amplitude of the sinusoidal waveform z(t)=715sin(165πt+2π÷468).

9. The power factor of a squirrel cage induction motor generally is ___________

10. Calculate the reactive power in a 7.2545 Ω resistor.