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

• 1. to increase the speed and hence generated e.m.f.
• 2. to increase the series flux
• 3. so that two similar machines will pass approximately equal currents to the load
• 4. to reduce the combined effect of ar-mature reaction of both machines

Question: The main factor which leads to unstable parallel operation of flat and over compounded generators is_____________?

• 1. their rising voltage characteristics
• 2. unequal number of turns in their series field windings
• 3. unequal speed regulation of their primemovers
• 4. unequal series field resistances

Question: 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______________?

• 1. reverse the field connections
• 2. increase the field resistance
• 3. increase the speed of primemover
• 4. check armature insulation resistance

Question: Which of the following generating machine will offer constant voltage on all loads?

• 1. Self-excited generator
• 2. Separately excited generator
• 3. Level compounded generator
• 4. All of the above

Question: Which of the following generators will be preferred if they are required to be run in parallel?

• 1. Shunt generators
• 2. Series generators
• 3. Compound generators
• 4. None of the above

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