Deck 17: The Synchronous Motor

Question 1

Once a motor accelerates to nearly ____________________% of synchronous speed, the field circuit is energized from the dc source.

Answer 1

95
ninety five
ninety-five

Question 2

Most large synchronous motors use an exciter that depends on brushes and slip rings.

Answer 2

False

Question 3

The Holtz motor has the same shaded-pole arrangement as the General Electric (Warren) motor.

Answer 3

True

Question 4

The leads for the stator windings are marked T₁, T₂, and T₃.

Question 5

List the components comprising a three-phase synchronous motor.

Question 6

The stator core and windings of a synchronous motor are different in construction compared to those of a three-phase squirrel-cage induction motor or a wound-rotor induction motor.

Question 7

A synchronous motor operating at no load has a torque angle of nearly ____________________ degrees.

Question 8

Selsyn is a contraction of the term ____________________.

Question 9

A(n) ____________________ differential system consists of a transmitter, a differential, and a receiver.

Question 10

What is the rotor speed for the single-phase, two-pole synchronous clock motor when operated from a 60-Hz source?

Question 11

The differential selsyn is really a multi-phase transformer.

Question 12

The ____________________ motor is a three-phase ac motor that operates at a constant speed from no load to full load.

Question 13

Explain the purpose of the field discharge resistor.

Question 14

Explain dc field excitation.

Question 15

Why is the synchronous motor used in many industrial applications?