Motor Control Q2

Front 1

What are some of the traits required of an electrician when troubleshooting electrical circuits

Back 1

A. Knowledge
B. logic
C. comprehension
D. Tenacity
E. Experience

Front 2

For an electrician to excel at troubleshooting they must have an understanding of and be able to interpret information gathered by using what knowledge sets

Back 2

A. electrical theory
B. diagrams and control schematics
C. component identification
D. proper use of testing devices
E. adherence to safety procedures

Front 3

What is normally the simplest part of a motor control system to troubleshoot

Back 3

The power circuit

Front 4

Where are most control circuits derived

Back 4

most are derived from the main power circuit that supplies power to the motor

Front 5

List the components found in most combination starters that are used to derive the control circuit

Back 5

A. primary control fuses
B. control transformer
C. secondary control fuses

Front 6

When troubleshooting energized circuits, all work and tests should be preformed in accordance with

Back 6

NFPA 70E

Front 7

Many times the failure in the power circuit is due to the loss of an _ _ device

Back 7

overcurrent protective

Front 8

_ are the most common type of OCPDs used in motor control circuit applications

Back 8

Fuses

Front 9

explain the condition know as single phasing

Back 9

a single phasing condition exists when one phase of a three phase system is not energized

Front 10

In a single phasing condition, if the _ are properly sized, the increased current will trip the overload relay.

Back 10

heaters

Front 11

what is the purpose of the control circuit

Back 11

the control circuit is designed to control the operation of the motor power power circuit and ultimately the motor itself

Front 12

list the basic categories of components utilized in control circuits

Back 12

A. pilot devices
B. indicating devices
C. relays
D. contactors

Front 13

what may be assumed if a control circuit was operating properly prior to its latest trouble

Back 13

that the circuit is wired properly and most likely, no wiring changes must be made

Front 14

list the four general troubleshooting methods

Back 14

A. logical
B. systematic
C. isolation and bypassing
D. spot checking

Front 15

the _ method is generally considered to be the first step when troubleshooting

Back 15

logical

Front 16

the _ method is normally considered to be the second step in troubleshooting

Back 16

systematic

Front 17

should the isolation method of troubleshooting be used alone

Back 17

No

Front 18

list the two types of isolation troubleshooting

Back 18

1. circuit isolation
2. device/component isolation

Front 19

_ is another effective method that is normally used in combination with isolation

Back 19

bypassing

Front 20

bypassing live control circuits is extremely dangerous and should be used as a

Back 20

last resort

Front 21

the _ approach is another name for spot checking

Back 21

Shotgun

Front 22

why should spot checking normally be avoided

Back 22

In most situations, spot checking is rarely successful, wastes time and leads to frustration

Front 23

using _ _ to troubleshoot control circuit problems can reduce the time required to resolve the trouble

Back 23

ladder diagram

Front 24

what drawing is useful in locating the physical location of electrical devices and components

Back 24

line diagram

Front 25

what type of diagram details how components interact with one another

Back 25

ladder diagrams

Front 26

when should the electrician not try to repair and restart a machine operation

Back 26

when the repair and restart may pose a danger to the operator and/or machine

Front 27

the cause of the _ should be determined prior to repairing or replacing a device or component.

Back 27

malfunction

Front 28

list the two most common devices areas where contactors fail

Back 28

1. solenoid coil
2. power contacts

Front 29

coil chatter is normally the result of a

Back 29

weak magnetic field

Front 30

what two conditions have the greatest influence on the strength of a coil's magnetic field

Back 30

1. reduced control voltages
2. impurities on the coil faces

Front 31

due to larger current draws, motor _ _ experience more sticking problems than _ _

Back 31

- power contacts
- control contacts

Front 32

what are the two common means of cleaning contactors

Back 32

1. contact cleaner
2. burnishing the contacts

Front 33

since a burnishing tool may not be readily available, a _ _ may be used in its place

Back 33

dollar bill

Front 34

what should one check first when confronted with a motor that will not start

Back 34

the overload relay

Front 35

what is the most common problem with visual indicating devices

Back 35

the light emitting component becomes defective

Front 36

when replacing a bad lamp, what considerations must be taken into account

Back 36

A. voltage of the lamp
B. wattage of the lamp

Front 37

the components in most audible devices are not often

Back 37

field replaceable