Deck 22: Starters and Speed Controllers

Question 1

The counter-emf controller is a commonly used method for the automatic ____ of a DC motor.

A)starting
B)deceleration
C)acceleration
D)stopping

Answer 1

C

Question 2

In automated equipment, the driven machine continuously feeds back information to a master control to maintain any reasonable combination of speed and ____ desired.

A)torque
B)temperature
C)vibration
D)pulses

Answer 2

A

Question 3

With the development of microprocessors and ____, a new product was born: the programmable controller.

A)DVD players
B)CD players
C)televisions
D)computers

Answer 3

D

Question 4

In automated machine operations, DC motors are driven by electronically controlled rectifiers that get their power directly from an AC line.

Question 5

Two types of manual speed controllers are used with shunt and cumulative compound motors, above-normal speed controllers and ____ speed controllers.

A)over-and-under
B)above-and-below-normal
C)below-normal
D)normal

Question 6

Starting ____ are designed to carry the starting current for only a short time; they are not intended for speed control.

A)rheostats
B)switches
C)motors
D)coils

Question 7

There are two types of series motor starters, one with no-voltage protection and the other with ____ protection.

A)voltage
B)high-voltage
C)no-load
D)high-load

Question 8

The PC is a solid-state device designed to perform the logic functions previously accomplished by electromechanical relays, drum switches, mechanical timers, and counters.

Question 9

Four-terminal manual starting has three functions in common with three-terminal starting rheostats.

Question 10

Inside the switch of a typical ____ controller is a series of contacts mounted on a movable cylinder.

A)series
B)drum
C)stationary
D)circular

Question 11

In some motor installations it is necessary to have a wide range of speed control, including both above-normal and below-normal speeds.

Question 12

Starting protection for any DC automatic controller consists of fuses or circuit breakers rated at ____% of the full-load current of the motor.

A)100
B)110
C)125
D)150

Question 13

When it is necessary not only to bring a motor to a quick stop but also to reverse the direction of rotation immediately, this is usually done by reversal of armature connections.

Question 14

The type of schematic diagram used to describe motor-control circuitry is often referred to as a ladder diagram or ____ ladder logic.

A)internal
B)motor
C)control
D)relay

Question 15

A contactor is a switch that is closed or opened by the magnetic pull of an energized relay coil.

Question 16

For the gentle starting of large motors, a motor starter is used.

Question 17

Series and cumulative compound motors are rarely used on cranes, elevators, machine tools, and other devices where the motor is under the direct control of an operator.

Question 18

The voltage drop acceleration controller makes use of the fact that at the instant of starting, armature current is low and voltage across the armature is high.

Question 19

Dynamic braking is a method for quickly using up the mechanical energy of motion of the armature and its mechanical load after the armature circuit is closed.

Question 20

When large DC motors require controlled steps of acceleration, a series of resistors connected to lockout relays provide the means for ____ motor acceleration.

A)smooth and uniform
B)quick
C)slow
D)only slight