Deck 31: Wound Rotor Motors

Question 1

Small wound rotor motors are often controlled manually by a three-pole make-before-break rotary switch.

Answer 1

True

Question 2

The difference between rotor speed and synchronous speed is called ____________________.

Answer 2

slip

Question 3

The wound rotor motor can be started in multiple steps to provide smooth acceleration from 0 RPM to maximum RPM.

Answer 3

True

Question 4

What are the three factors that determine the amount of torque developed by a three phase induction motor?

Question 5

Maximum torque is developed when the ____________________ of the stator and rotor are in-phase with each other.

Question 6

The wound rotor induction motor is often called the ____________________ motor.

Question 7

The operating characteristics of a wound rotor motor with the rotor leads shorted together are very similar to those of a(n) ____________________ motor.

Question 8

Starting circuits generally employ resistors of a lower wattage value than circuits that are intended for speed control.

Question 9

The wound rotor motor has a lower starting torque per amp of starting current than any other type of three phase motor.

Question 10

In an alternating current circuit, the current limiting effect of a capacitor is called ____________________.

Question 11

How is the construction of the rotor different between the wound rotor induction motor and the squirrel cage motor?

Question 12

Capacitive reactance is proportional to the rotor frequency.

Question 13

What is the principle on which frequency control operates?

Question 14

What is one advantage and one disadvantage of frequency control?

Question 15

How is the starting current and speed of a wound rotor induction motor controlled?