Unit 19 Quiz

Question 1

Reserve a capacity of a motor.

Answer 1

Motor service factor

Question 2

May be used in place of the bimetal.

Answer 2

Solder pot

Question 3

Not affected by ambient temperatures and can be located in hot areas.

Answer 3

Magnetic overload protection.

Question 4

Has moveable and stationary contacts and can be rebuilt.

Answer 4

Contactor

Question 5

Used to switch on/off larger contacts and starters.

Answer 5

Pilot duty relay

Question 6

Throw away device because parts are not available for rebuilding it.

Answer 6

Relay

Question 7

Overload protection located near or imbedded in the motor windings.

Answer 7

Inherent motor protection

Question 8

Designed to keep the motor from restarting.

Answer 8

Manual reset

Question 9

True or false: All bimetal elements are designed with snap action to avoid excessive arcing.

Answer 9

True

Question 10

True or false: Magnetic overload devices are attached to the motor starter.

Answer 10

False

Question 11

True or false: Overload protection is divided into inherent and external protection.

Answer 11

True

Question 12

True or false: Resistance in the surface of the contact may cause the contacts to heat up and loss of spring tension.

Answer 12

True

Question 13

True or false: In some instances, motor starter protection can indicate a motor problem better than the motor winding thermostat protection.

Answer 13

True

Question 14

True or false: Voltage drop across contacts indicates a bad power source.

Answer 14

False

Question 15

True or false: Silver cadmium oxide contacts are used in relays that are used for heavier duty motor switching relays.

Answer 15

True

Question 16

True or false: A set of contacts are closed when the relay is energized. These contacts are classified as normally closed.

Answer 16

False

Question 17

True or false: Fuses are used as motor protectors.

Answer 17

False

Question 18

True or false: Bimetal and solder pot overload devices are thermally operated.

Answer 18

True

Question 19

True or false: A sure sign of contact failure is discoloration on the contact surfaces.

Answer 19

True

Question 20

The contactor is a _____ with electrical contacts.

Answer 20

Magnetic coil

Question 21

What is the difference between a relay and a potential relay?

Answer 21

*The amount of current each can handle.
*Potential relay utilize a capacitor (BEMF is utilized)

Question 22

_______ contacts are rated at lower amperages than the main contacts.

Answer 22

Auxiliary

Question 23

Relays are designed to control loads that draw less than _____ amps of electric current.

Answer 23

20

Question 24

What is the difference between a starter and a contactor?

Answer 24

Starters has built in overload

Question 25

Using your meter, how can you tell a set of contacts are going bad?

Answer 25

Low voltage, if you use resistance, “O” resistance is good, 0.5 = starting to go bad
1.0= bad

Question 26

How are line and load terminals distinguished on a contactor or motor starter?

Answer 26

T= Terminal
L= Line
(There will be a diagram or letters with numbers on the component).

Question 27

The moving armature in a contactor is actuated by ______.

Answer 27

The solenoid coil

Question 28

A common practice in condensing units is to use a contactor with only one set of contacts opening only one side of the power to the unit. This is to ______.

Answer 28

Provide off-cycle heat to the compressor

Question 29

When a contactor’s coil is energized, how much resistance should be measured between terminals L1 and terminal T1?

Answer 29

0 ohms

Question 30

An inherent motor protector is a ____.

Answer 30

Thermally activated device in the motor winding.

Question 31

The service factor of an electric motor is determined by ______.

Answer 31

Motor’s reserve capacity

Question 32

Standards for motor overload protection are set by the _____.

Answer 32

National Electrical Code (NEC)

Question 33

A solder pot is part of a ______.

Answer 33

Resettable circuit breaker

Question 34

If a normally operating motor draws 75 amps on startup, it will most likely draw ______ amps when running.

Answer 34

15 FLA

75 LRA/5= 15FLA

Question 35

Use the diagram of the relay below to answer questions 35-37.

What terminals are the NO contacts?

Answer 35

2 &4

Question 36

What terminals are the NC contacts?

Answer 36

4 & 5

Question 37

What are terminals 1 & 3 used for?

Answer 37

Coil

Question 38

Draw the electrical symbol for a DPST contact configuration.

Answer 38

Question 39

Extra Credit:
1. Draw the electrical symbol for a normally closed contact.

Answer 39

Question 40

Extra Credit:

How many poles and how many throws. (See contactors at front desk when turning in your paper).

2. ____ poles ______ throws

Answer 40

2 & 1

Question 41

Extra Credit:

How many poles and how many throws. (See contactors at front desk when turning in your paper).

3. _____ poles _____ throws

Answer 41

1 & 1

Question 42

Extra Credit:

How many poles and how many throws. (See contactors at front desk when turning in your paper).

4. _____ poles _____ throws

Answer 42

3 & 1

Question 43

Is the relay good or bad? (See relay at front desk when turning in your paper)

Answer 43

Bad

Question 44

Extra Credit:
6. Multiple thermocouples wired in series are called a ________.

Answer 44

Thermopile

Question 45

Extra Credit:
7. Technician “A” says that if you take a voltage reading from terminal L1 to terminal T1 on a contactor whose coil is energized, you should read zero volts. Technician “B” says that contactors can only have normally open contacts. Which of the following statements is correct?

Answer 45

Technician “A” is correct. Technician “B” is incorrect.