4

Question 1

Pole

Answer 1

a number of completely isolated circuits a relay can switch at one time

Question 2

throw

Answer 2

the number of closed contact positions per pole

Question 3

break

Answer 3

the number of separate places on a contact that open or close an electric circuit

Question 4

describe the operation of a NCTC contact

Answer 4

opens instantly when energized closes on timer when reenergized

Question 5

_____ timers are more accurate than _____ timers because they have no moving parts in their timing circuit that might be affected by heat humidity or pressure.

Answer 5

solid state / dashpot

Question 6

since a contact has no voltage drop, placing it in parallel with load would create a _____

Answer 6

short circuit

Question 7

which of the following features is typically not present on a magnetic contractor, but is present on a motor starter.

Answer 7

overload relays

Question 8

solenoids convert electrical energy directly into ______ motion

Answer 8

mechanical

Question 9

REED

Answer 9

a fast operating, single pole, single throw switch with normally open contacts hermetically sealed in a glass envelope

Question 10

A repeat cycle timer is activated, and the load is energized for 15 seconds, and then reenergized for 30 seconds, with the cycle repeating continuously until the timer is deactivated. This timer is programmed for _______ operation.

Answer 10

asymmetrical

Question 11

a dode timer has a single normally open contact. If the timer is set for 15 second delay, which of the following scenarios describes when the contact will change state from open to closed in the timing sequence

Answer 11

instantaneously, when the timer is energized

Question 12

which of the following types of timers does not have an instantaneous contact available, which will close immediately when energized, before the timer times out

Answer 12

DOE electronic timer

Question 13

the surface that most starter contacts is made from is _________

Answer 13

silver cadmium alloy composite

Question 14

list the 3 basic parts of an AC solenoid

Answer 14

frame (support)
coil
armature (plunger)

Question 15

during the operation of a timer, when do the instantaneous contacts change state?

Answer 15

when the coil is energized

Question 16

name the 3 major factors that led to the discontinuation of knife switches to control motors

Answer 16

1 exposed live parts
2 soft copper arcing led to failure
3 opening and closing speed was determined by the operator

Question 17

what are 2 types of thermal overload relays

Answer 17

eutectic alloy

bi-metallic

Question 18

the damage to a motor caused by an overload is proportional to what 2 factors?

Answer 18

amount of current

direction of overload

Question 19

list 3 basic methods that timers use to control timing

Answer 19

synchronous
dashpot
solid state

Question 20

what are the 4 types of timing functions that electronic timers are capable of

Answer 20

delay on
delay off
recycle
one-shot

Question 21

what are 3 basic types of overload relays

Answer 21

magnetic
thermal
electronic

Question 22

list 2 reasons timing circuits are used in motor control applications

Answer 22

1 - to enable process events that are started and stopped at different intervals

2 - to reduce the need for multiple machine operators