When two D.C. generators are running in parallel an equilizer bar is used______________?
(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
Two generators are running in parallel. One of the generators may run as motor for which of the following reasons ?
(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 share of loads
Which of the following generators will be preferred if they are required to be run in parallel?
(A) Shunt generators
(B) Series generators
(C) Compound generators
(D) None of the above
Which of the following generating machine will offer constant voltage on all loads?
(A) Self-excited generator
(B) Separately excited generator
(C) Level compounded generator
(D) All of the above
If a self excited D.C. generator after being installed, fails to build up on its first trial run, the first thing to do is to______________?
(A) reverse the field connections
(B) increase the field resistance
(C) increase the speed of primemover
(D) check armature insulation resistance
The main factor which leads to unstable parallel operation of flat and over compounded generators is_____________?
(A) their rising voltage characteristics
(B) unequal number of turns in their series field windings
(C) unequal speed regulation of their primemovers
(D) unequal series field resistances
When two D.C. series generators are running in parallel, an equilizer bar is used________________?
(A) to increase the speed and hence generated e.m.f.
(B) to increase the series flux
(C) so that two similar machines will pass approximately equal currents to the load
(D) to reduce the combined effect of ar-mature reaction of both machines
Shunt generators are most suited for stable parallel operation because of their______________?
(A) rising voltage characteristics
(B) identical voltage characteristics
(C) drooping voltage characteristics
(D) linear voltage characteristics
As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately______________?
(A) 40 percent
(B) 25 percent
(C) 10 percent
(D) 5 percent
The shaft of an induction motor is made of_____________?
(A) high speed steel
(B) stainless steel
(C) carbon steel
(D) cast iron