Deck 7: Magnetic Relays and Contactors

Question 1

The current level where the armature returns to the de-energized position is called the ____ current.

A)pull-out
B)base
C)dropout
D)leveling

Answer 1

C

Question 2

The term _______________ refers to the number of separate power circuits that can be switched.

Answer 2

pole

Question 3

The term _______________ refers to the number of states that the power circuits can be switched into.

Answer 3

throw

Question 4

The minimum current required to actuate a device is called the ____ current, and is determined by the applied voltage.

A)pull-out
B)pull-in
C)drop-out
D)drop-in

Question 5

____ relays provide a delayed action, changing operating states of the contacts associated with its control coil.

A)Delay
B)Pause
C)Timing
D)Contactor

Question 6

Relay contact faces are ____.

A)straight
B)triangular
C)angular
D)domed

Question 7

____ relays are small, completely self-contained, and plug into bases with pins that protrude out the back.

A)Ice-cube
B)Frozen
C)Square
D)Water

Question 8

Describe the purpose of arc chutes.

Question 9

Describe pull-in and dropout current.

Question 10

_______________ is a measure of how easily a medium can carry magnetic lines of flux and become magnetized.

Question 11

____ is a motor control function to stop an induction motor by temporarily applying the full line-voltage of a motor in the reverse direction of rotation than the motor is turning in.

A)Plugging
B)Jogging
C)Timing
D)Contactor

Question 12

____ is a motor control function where the motor is energized for only an instant, either to verify the direction of rotation for the motor, or possibly to position or align a machine part.

A)Plugging
B)Jogging
C)Timing
D)Contactor

Question 13

When the control coil is energized, the resulting magnetic forces will draw the armature away from the core.

Question 14

The pin-out information identifies the pin numbers on the relay base to which each contact point of the relay is connected.

Question 15

____ are found in the power circuit.

A)Timing relays
B)Contactors
C)Callouts
D)Armatures

Question 16

The ____ provides the physical structure that holds the relay together, and is made of iron to provide a low permeability path to guide the magnetic lines of flux of the control coil.

A)yoke
B)armature
C)current
D)coil

Question 17

The _______________ coil is a coil of wire wound around an iron core, and when energized the two become an electro-magnet.

Question 18

The movable part of the relay is called the ____.

A)control coil
B)yoke
C)armature
D)medium

Question 19

_______________ chute plates are placed in close proximity to where the contacts open, and they use both mass and space properties to help extinguish the electrical arc before it becomes too large.

Question 20

_______________ is a generic term sometimes used to document relay contact configurations on ladder and print diagrams.