Operational Electrical Engineering Interview Questions & Answers:

1. In a star connected three phase transformer the

* a) Three phases are connected together at the start point
* b) Three phases are separate
* c) Neutral conductor is connected to a single phase
* d) Neutral conductor is electrically separated

Answer - a

2. A single-phase double-wound transformer consists of

* a) A single core mounted winding
* b) A winding that carries the difference between IP and IS
* c) A single solid core
* d) Two electrically separated coils

Answer - d

3. One method of insulating windings is to use

* a) Shelac
* b) High reluctance silicon steel
* c) Low frequency dust cores
* d) PVC

Answer - a

4. The usual method of insulating core laminations is

* a) Low reluctance silicon steel
* b) Surface oxidization
* c) High frequency air cores
* d) Cellulose paper

Answer - b

5. If a motor is required to start against a large starting current, it is usual to use

* a) Direct on line starter
* b) Face plate starter
* c) Step down centre tapped starter
* d) Rotor resistance starter

Answer - d

6. In a shunt-wound motor the field coil is connected in

* a) Series with the armature
* b) Series with the motor
* c) parallel with the armature
* d) parallel with the motor

Answer - c

7. When the field windings of an electrical machine are not connected to its own armature, it is known as

* a) Self- excited
* b) Polyphase
* c) Separately-excited
* d) Synchronous

Answer - c

8. With a star-delta starter, the windings are brought out to a terminal box. The voltage applied to the windings at starting is

* a) VL ÷ v3
* b) VL x v3
* c) VPhase ÷ v3
* d) VPhase x v3

Answer - a

9. Particular starting arrangements are used when a motor has a rating greater than

* a) 370 microwatts
* b) 0.37 watts
* c) 37 watts
* d) 370 watts

Answer - d

10. An isolator built into a panel is used for

* a) Normal load switching
* b) Fault load switching
* c) Short circuit protection
* d) No load switching

Answer - d