Unit 12 Test

Question 1

What is a device that opens or closes a set of contacts when its coil is energized, which usually carries less than 20 amperes?

Answer 1

Relay

Question 2

What is a device that decreases the input voltage?

Answer 2

Transformer

Question 3

What is a schematic that cross references the components and their lettered designations?

Answer 3

Legend

Question 4

What is the simplest type of overload?

Answer 4

Overload (thermal)

Question 5

What type of system heats a conditioned space by reversing the refrigeration cycle?

Answer 5

Heat Pump

Question 6

Devices such as motors, solenoids, heaters, and signal lights are called what?

Answer 6

Load

Question 7

What is the device called that breaks the circuit when a high current draw exists?

Answer 7

Fuse

Question 8

What kind of device is used to rotate a compressor?

Answer 8

Motor

Question 9

What’s the type of electrical device that opens or closes to control a load?

Answer 9

Switch

Question 10

What are the two types of contact?

Answer 10

Normally Open and Normally Closed (might be poles)

Question 11

What do we call a contactor with a means of overload protection?

Answer 11

Magnetic Starter

Question 12

What’s another name for a line or label diagram?

Answer 12

Pictorial Schematic

Question 13

What is the position of an electrical device that is open when the device is de-energized?

Answer 13

Normally Open

Question 14

What do we call a device that responds to a temperature change by opening and closing a set of contacts?

Answer 14

Thermostat

Question 15

What is the term used to describe the number of positions of a set of movable contacts?

Answer 15

Throw

Question 16

What’s the name of a wiring diagram that is laid out in a circuit-by-circuit arrangement?

Answer 16

Schematic Diagram

Question 17

What do we call the position of an electrical device that is closed when it’s de-energized?

Answer 17

Normally Closed

Question 18

What do we call a device that opens and closes a set of contacts, and it’s capable of carrying loads in excess of 20 amperes?

Answer 18

Contactor

Question 19

What do we call it when we supply electrical energy?

Answer 19

Energized

Question 20

What’s the device that breaks the control circuit during a motor overload?

Answer 20

Pilot Duty

Question 21

What do we call the material that retards the flow of electrons?

Answer 21

Insulator

Question 22

What do you set your meter to be able to read resistance?

Answer 22

Ohms (Ω)

Question 23

Resistance is the term used to describe the opposition to electron flow. (True or False)

Answer 23

True

Question 24

When current is flowing through a conductor, amperage is produced around the conductor. (True or False)

Answer 24

False

Question 25

When checking the amperes of a circuit, the ammeter should be clamped around two wires in the circuit. (True or False)

Answer 25

False

Question 26

If a single conductor of a circuit is wrapped around the jaws of a clamp ammeter six times and the reading is 24 amps, what is the true amp reading?

Answer 26

4 Amps

Question 27

A complete circuit, with no open switches or broken wires, is said to have what?

Answer 27

Continuity

Question 28

Voltage is equal to amperage times resistance. (True or False)

Answer 28

True

Question 29

The amperage draw of a series circuit is equal to the voltage divided by the total resistance. (True or False)

Answer 29

True

Question 30

What is the resistance reading of a good motor winding?

Answer 30

Low (typically near 0 ohms)

Question 31

If you’re reading infinity on your ohmmeter when checking a motor winding for resistance, it indicates the winding is what?

Answer 31

Open

Question 32

Given a 115-volt and 25-amp series circuit with three resistance values (R1 is 100 Ohms, R2 is 160 Ohms, and R3 is 200 Ohms), what is the total voltage drop throughout the circuit?

Answer 32

115 Volts

(Series circuit, the voltage drop equals the source of voltage)

Question 33

Given a 115-volt and 25-amp series circuit with three resistance values (R1 is 100 Ohms, R2 is 160 Ohms, and R3 is 200 Ohms), what is the total resistance of the circuit?

Answer 33

460 Ohms
(Series circuit, total resistance equals the sum of individual resistances: R1 + R2 + R3 = Total)

Question 34

If we had a 440-volt parallel circuit with two resistance values (R1 is 220 ohms, and R2 is 220 ohms), what is the total amp draw of that circuit?

Answer 34

4 Amps
(Parallel circuit, 1/R total = 1/R1 + 1/R2);
I = V/R)

Question 35

If we had a 440-volt parallel circuit with two resistance values (R1 is 220 ohms, and R2 is 220 ohms), what is the total resistance of that circuit?

Answer 35

110 Ohms
(1/R Total = 1/R1 + 1/R2)

Question 36

In HVAC systems, the common low-voltage wire colors are typically as follows:

•	Red (R):

Answer 36

Power (24V AC)

Question 37

In HVAC systems, the common low-voltage wire colors are typically as follows:

•	White (W):

Answer 37

Heating

Question 38

In HVAC systems, the common low-voltage wire colors are typically as follows:

•	Yellow (Y):

Answer 38

Cooling(Thermostat/contactor)

Question 39

In HVAC systems, the common low-voltage wire colors are typically as follows:

•	Green (G):

Answer 39

Fan

Question 40

In HVAC systems, the common low-voltage wire colors are typically as follows:

•	Blue (C):

Answer 40

Common

Question 41

In HVAC systems, the common low-voltage wire colors are typically as follows:

•	Orange (O):

Answer 41

Heat Pump