CHAPTER 33

Question 1

In a three phase , motor the speed of rotation of the magnetic field is called the _______ speed.

Answer 1

synchronous

Question 2

To reverse the direction of a three -phase motor, reverse _________.

Answer 2

any two leads (Stator Leads)

Question 3

If a piece of machinery needs a replacement motor and will be damages if the new motor rotates the wrong way. The test equipment needed to test the rotation direction of the new motor is a ______.

Answer 3

phase rotation meter

Question 4

Some motor are constructed so that they will operate on either of two voltages. When they are connected to operate on a higher voltages, the two voltages, the winding are connected in ______.

Answer 4

series

Question 5

Some motor are constructed so that they will operate on either of two voltages. When they are connected to operate on a lower of the two voltages, the winding are connected in ______.

Answer 5

parallel

Question 6

The squirrel-cage rotor is constructed of _____ and end _____ embedded in steel laminations.

Answer 6

bars,rings

Question 7

The torque of a squirrel-cage induction motor will be maximum when the phase angle between the stator and rotor field is _____.

Answer 7

90 Degrees out of phase

Question 8

When a squirrel-cage motor is first started, the value of the current draw is _____.

Answer 8

several times the running current.

Question 9

The synchronous motor is an induction motor.

Answer 9

Faust

Question 10

in the consequent pole motor, if the number of poles is doubled, the motor speed will be _____.

Answer 10

cut in half

Question 11

A motor is operating at 3450 RPM and is producing a torque of 32 lb-in. What is the output horsepower of the motor

Answer 11

HP = 6.28 x rpm x L x P / 33,000

Question 12

The wound-rotor induction is popular in industry because it has _____ starting torque and _____ start current.

Answer 12

high, low

Question 13

The set of squirrel-cage bars on the rotor of a synchronous motor is used to start the motor and is know as the____.

Answer 13

amortisseur winding

Question 14

A synchronous motor operate with no load and used for power factor correction is sometimes called a ______.

Answer 14

synchronous condenser

Question 15

Selsyn motors operate on _____ voltage.

Answer 15

single-phase

Question 16

The differential selsyn has three stator windings connected in a wye and a rotor made of ______.

Answer 16

three windings connected in a wye.