Deck 33: Consequent Pole Motors

Question 1

In a circuit for controlling a four-speed, three phase consequent pole motor, how is any speed selected?

Answer 1

The control permits any speed to be selected by pushing the button that initiates that particular speed.

Question 2

What are the two factors that determine the synchronous speed of an AC motor?

Answer 2

Two factors determine the synchronous speed of an AC motor:
1) Frequency of the applied voltage
2) Number of stator poles per phase

Question 3

Explain how the direction of current flow determines the number of poles.

Answer 3

If the current travels in the same direction through two pole pieces, both produce the same magnetic polarity and are essentially one pole piece. If the current direction is opposite through each pole piece, they produce opposite magnetic polarities and are essentially two poles.

Question 4

Consequent pole motors have the ability to change speed by changing the number of ____________________.

Question 5

The magnetic field makes one ____________________ of a two-pole motor each complete cycle.

Question 6

A three phase, two-pole motor contains eight actual poles.

Question 7

Why are eleven pin control relays used to provide interlock protection?

Question 8

Figure 33-7
The circuit shown in the accompanying figure forces the motor to start in high speed.

Question 9

Three-speed consequent pole motors can be wound to produce constant horsepower, constant torque, or variable torque.

Question 10

If the winding is such that the series delta gives the low speed and the parallel wye gives the high speed, the torque will be the same for both speeds.

Question 11

The magnetic field travels through the same number of poles during each complete cycle.

Question 12

The number of stator poles is changed by redirecting the ____________________ through pairs of poles.

Question 13

Figure 33-10
The above figure shows a four-speed, two-winding three phase consequent pole motor with constant ____________________.

Question 14

How many windings do consequent pole motors that are intended to operate with three speeds have?

Question 15

Consequent pole motors intended to operate with four speeds use ____________________ reconnectable windings.