Page 799 - Basic Electrical Engineering

c. unity
d. zero lagging.

9. The voltage regulation of a synchronous generator will always be positive when the load
power factor is

a. leading
b. lagging
c. zero leading
d. above 0.8 leading.

10. The speed regulation of a synchronous machine is

a. unity
b. zero
c. less than unity
d. none.

11. For lagging power factor load, the relationship between the induced EMF E and the terminal
±
voltage v, can be expressed as

2 2 2
a. E = (Vcos ϕ + I R ) + (Vsin ϕ + I X )
a a
a s
2 2
b. E = (Vcos ϕ + I R ) + (Vsin ϕ + I X )
a a
a s
c. E = (Vcos ϕ + I R ) + (Vsin ϕ + I X )
a s
a a
d. E = (Vcos ϕ + I R ) – (Vsin ϕ + I X ).
a a
a s
12. For synchronizing an alternator with the busbar which of the following conditions is not
applicable?
a. The generated voltage of the alternator should be equal to the busbar voltage
b. The frequency of the generated voltage should be equal to the busbar frequency
c. The phase sequence of the voltage generated should be the same as that of busbar
voltage
d. The KVA rating of the alternator should be equal to the KVA rating of other
alternators already connected to the busbar.

13. Sharing of load by two alternators running in parallel can be achieved by

a. change of excitation
b. change of speed
c. change of prime mover input
d. change of excitation.

14. Which of the following statements is not true for a synchronous motor?

a. An over-excited synchronous motor draws lagging power factor current