Electrical Engineering MCQs on DC Generator

Contents

- 1 Brushes of DC machines are made of
- 2 In generators, lap winding is employed for
- 3 A cumulatively compounded long shunt generator when operated as a motor would be
- 4 Magnetic field in generator is produced using
- 5 In case of flat compounded generator
- 6 In a DC generator the critical resistance can be increased by
- 7 Lap winding comprises of
- 8 The bearings used to support the rotor shafts are usually
- 9 A shunt generator can self-excite if
- 10 The generator can be considered as a

## Brushes of DC machines are made of

Brushes of DC machines are made of

- Carbon
- Hard copper
- Soft copper
- All of these

Correct answer: 1. Carbon

## In generators, lap winding is employed for

In generators, lap winding is employed for

- High voltage, high current
- High voltage, low current
- Low voltage, high current
- Low voltage, low current

Correct answer: 3. Low voltage, high current

## A cumulatively compounded long shunt generator when operated as a motor would be

A cumulatively compounded long shunt generator when operated as a motor would be

- Cumulatively compounded long shunt
- Cumulatively compounded short shunt
- Differentially compounded long shunt
- Differentially compounded short shunt

Correct answer: 3. Differentially compounded long shunt

## Magnetic field in generator is produced using

Magnetic field in generator is produced using

- Electromagnets
- Permanent magnets
- Both of above
- None of above

Correct answer: 1. Electromagnets

## In case of flat compounded generator

In case of flat compounded generator

- Generated voltage is proportional to the load on the generator
- Speed varies in proportion to the load on the generator
- Voltage generated is less than the rated voltage
- Voltage remains constant irrespective of the load

Correct answer: 4. Voltage remains constant irrespective of the load

## In a DC generator the critical resistance can be increased by

In a DC generator the critical resistance can be increased by

- Decreasing its field resistance
- Decreasing its speed
- Increasing its field resistance
- Increasing its speed

Correct answer: 4. Increasing its speed

## Lap winding comprises of

Lap winding comprises of

- Even number of conductors
- Odd number of conductors
- Any of above
- None of above

Correct answer: 1. Even number of conductors

## The bearings used to support the rotor shafts are usually

The bearings used to support the rotor shafts are usually

- Ball bearings
- Bush bearings
- Magnetic bearings
- Needle bearings

Correct answer: 1. Ball bearings

## A shunt generator can self-excite if

A shunt generator can self-excite if

- Irrespective of the value of the resistance in the field circuit
- Resistance of the field circuit is greater than critical value
- Resistance of the field circuit is less than critical value
- None of these

Correct answer: 3. Resistance of the field circuit is less than critical value

## The generator can be considered as a

The generator can be considered as a

- Power pump
- Prime mover
- Rectifier
- Rotating amplifier

Correct answer: 4. Rotating amplifier