A. Lenz’s law
B. Ohm’s law
C. Faraday’s law of electromagnetic induction
D. none of the above
A D.C. generator works on the principle of____________? Read More »
D.C. Generators A. only if the load current is zero
B. only if the load current is not zero
C. irrespective of the value of load current
D. none of the above
A series generator can self-excite:______________? Read More »
D.C. Generators A. will be less than 250 V
B. will always be 250 V
C. may be greater or less than 250 V
D. none of the above
A. 150 V
B. less than 150 V
C. greater than 150 V
D. none of the above
A. only if the resistance of the field circuit is less than critical value
B. only if the resistance of the field circuit is greater than critical value
C. irrespective of the value of the resistance in the field circuit
D. none
A shunt generator can self-excite:_________________? Read More »
D.C. Generators A. 100% regulation
B. infinite regulation
C. 50% regulation
D. 1% regulation
With a D.C. generator which of the following regulation is preferred ? Read More »
D.C. Generators A. 270 V
B. 267.5 V
C. 265 V
D. 257.4 V
A. same kW rating
B. the same operation r.p.m.
C. the same droog voltage characteristics
D. same percentage regulation
A. to increase the series flux
B. to increase the generated e.m.f.
C. to reduce the combined effect of ar-mature reaction of both the machines
D. so that the two identical machines will pass approximately equal cur¬rents to the load
When two D.C. generators are running in parallel an equilizer bar is used______________? Read More »
D.C. Generators A. The direction of that generator is reversed
B. The speed of that generator is increased
C. The field of that generator is weakened
D. That generator takes large of loads
