Test

Question 1

The windings of a 3 phase motor are physically positioned in the stator so they

Answer 1

Oppose each other creating a magnetic field causing it to rotate

Question 2

2 maths

Answer 2

Check

Question 3

3 maths

Answer 3

Check

Question 4

What is the principle of induction in a 3 phase motor

Answer 4

The magnetic flux caused by the stator current interacts with the magnetic flux caused by the rotor current in such a way they the rotor moves in the direction of the rotating magnetic field

Question 5

Where are the windings of a 3 phase squirrel cage motor found

Answer 5

In the inner lining of the stator

Question 6

What type of rotor has slip rings

Answer 6

Permanent capacitor motor

Question 7

When testing the insulation resistance to earth of a 415v 3 phase induction motor, the minimum acceptable reading is

Answer 7

<200M ohm

Question 8

The centrifugal switch should disconnect the start winding when it reaches

Answer 8

75% Synchronous speed

Question 9

Split phase induction motors are best used to power

Answer 9

Multi speed air-conditioner fans

Question 10

How can rotational directions of a split phase motor be reversed

Answer 10

Switch the winding configurations around on either run or start

Question 11

A cap start motor has the in series with which 2 parts

Answer 11

Centrifugal switch and start winding

Question 12

Cap start motors are best suited to power

Answer 12

Washing machines

Question 13

Mechanical to electrical

Electrical to mechanical

Answer 13

Alternator

Motor

Question 14

A 3 phase induction motor can be used as a synchronous generator providing the prime mover drives the rotor

Answer 14

At the rated name plate speed of the motor

Question 15

Name 4 of the main parts of a synchronous alternator/motor

Answer 15

Stator, windings, rotor, frame

Question 16

Alternators that obtain their dc field supply from an external source are said to be

Answer 16

Separately excited

Question 17

23

Answer 17

Voltage regulator - Alternator - exciter

Question 18

If a self excited single phase alternator fails to produce at its output terminals with the prime mover running what. will happen

Answer 18

Windings will burn out and it will get damaged

Question 19

Large 3 phase synchronous motors may have their rotor dc windings short circuited to become an induction motor and then have the short removed and dc applied to the rotor because

Answer 19

Leading powerfactor loads require this