Question: Two generators are running in parallel. One of the generators may run as motor for which of the following reasons ?

• 1. The direction of that generator is reversed
• 2. The speed of that generator is increased
• 3. The field of that generator is weakened
• 4. That generator takes large share of loads

Question: When two D.C. generators are running in parallel an equilizer bar is used______________?

• 1. to increase the series flux
• 2. to increase the generated e.m.f.
• 3. to reduce the combined effect of ar-mature reaction of both the machines
• 4. so that the two identical machines will pass approximately equal cur¬rents to the load

Question: The essential condition for parallel operation of two D.C. generators is that they have ________________?

• 1. same kW rating
• 2. the same operation r.p.m.
• 3. the same drooping voltage characteristics
• 4. same percentage regulation

Question: Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be________

• 1. 270 V
• 2. 267.5 V
• 3. 265 V
• 4. 257.4 V

Question: With a D.C. generator which of the following regulation is preferred ?

• 1. 100% regulation
• 2. infinite regulation
• 3. 50% regulation
• 4. 1% regulation

Question: A shunt generator can self-excite:_________________?

• 1. only if the resistance of the field circuit is less than critical value
• 2. only if the resistance of the field circuit is greater than critical value
• 3. irrespective of the value of the resistance in the field circuit
• 4. none

Question: The terminal voltage of a series generator is 150 V when the load current is 5 A. If the load current is increased to 10 A, the terminal voltage will be____________?

• 1. 150 V
• 2. less than 150 V
• 3. greater than 150 V
• 4. none of the above

Question: The open circuit voltage of a compound generator is 250 V. At full load the terminal voltage____________?

• 1. will be less than 250 V
• 2. will always be 250 V
• 3. may be greater or less than 250 V
• 4. none of the above

Question: A series generator can self-excite:______________?

• 1. only if the load current is zero
• 2. only if the load current is not zero
• 3. irrespective of the value of load current
• 4. none of the above

Question: A D.C. generator works on the principle of____________?

• 1. Lenz’s law
• 2. Ohm’s law
• 3. Faraday’s law of electromagnetic induction
• 4. none of the above