Synchronous Motor MCQ Part 3

by

Synchronous motor MCQ Part 3

The synchronous motor is best described as

The synchronous motor is best described as:

  1. Singly fed motor
  2. Variable power factor motor
  3. Variable speed motor
  4. None of the above

Correct answer: 2. Variable power factor motor

The synchronous motor is best described as since it can operate at different power factors

What is synchronous capacitor

A synchronous capacitor is:

  1. An under excited synchronous motor
  2. An overexcited synchronous motor
  3. An ordinary capacitor bank
  4. A synchronous generator

Correct answer: 2. An over excited synchronous motor

A synchronous capacitor or synchronous condenser is actually a synchronous motor that is operating overexcited.

If field excitation of synchronous motor is increased then the armature current will

If field excitation of a synchronous motor is increased then the armature current will:

  1. Remain same
  2. Decrease
  3. Increase
  4. Slightly decrease

Correct answer: 3. Increase

If field excitation of a synchronous motor is increased then the armature current will also increase

A synchronous motor runs at only one speed owing to fact that

A synchronous motor runs at only one speed owing to fact that:

  1. It has amortisseur winding
  2. It is singly fed
  3. It is doubly-fed
  4. It has low losses

Correct answer: 3. It is doubly-fed

In Synchronous motors, the electricity is supplied to both the field and armature windings (thus the name double fed is give). This condition restricts synchronous motor to develop torque at only one speed: The synchronous speed.

What is the output power (in kW) supplied by a synchronous motor to 20 HP load

What is the output power (in kW) supplied by a synchronous motor to 20 HP load:

  1. 10.3 kW
  2. 11.44 kW
  3. 13.76 kW
  4. 14.92 kW

Correct answer: 4. 14.92 kW

Pout = 20 * 0.746 = 14.92 kW

Leave a Comment