Deck 35: Solid State Dc Motor Controls

Question 1

A very common method of detecting motor speed is with the use of a(n) ____________________.

Answer 1

electrotachometer

Question 2

An electrotachometer is connected to the ____________________.

Answer 2

motor shaft

Question 3

The armature of a large DC motor has high resistance.

Answer 3

False

Question 4

Output voltage control is achieved by ____________________ the SCRs.

Question 5

How is normal speed for a DC motor obtained?

Question 6

A DC motor is generally operated at or below normal speed.

Question 7

In a field failure control, what happens if the voltage falls below a certain level?

Question 8

If current flow through the shunt field is interrupted, a compound wound, DC motor will become a series motor and race to high speeds.

Question 9

What is an electrotachometer?

Question 10

How is a DC motor operated below normal?

Question 11

Speed control of a DC motor is much smoother if two separate ____________________, which convert the AC voltage to DC voltage, are used to control the motor instead of resistors connected in series with the armature.

Question 12

Why do most solid-state DC motor controls use some method to limit the current to a safe value?

Question 13

The greatest advantage of using direct current motors is their variable ____________________ characteristic.

Question 14

The shunt field power supply is generally designed to remain turned on even when the main (armature) power supply is turned off.

Question 15

If load is added to a motor, the motor speed increases.