Nait 4Th Period Electrical

Front 1

Voltage measurement is taken

Back 1

Parallel and power on

Front 2

Amperage measurement is taken

Back 2

Series & power on

Front 3

Ohms measurement taken

Back 3

Parallel & power off

Front 4

Never connect ammeter to a circuit that is connected in

Back 4

Parallel to the load

Front 5

If a voltage across contacts reads “0” then the contacts are

Back 5

Closed

Front 6

List 3 devices needed for a circuit

Back 6

Power source

Switch

Load (appliance)

Front 7

An operating control does this

Back 7

Starts and stops equipment

Front 8

Primary controls do this

Back 8

Activate directly by operating control

Front 9

The 3 variations of a schematic are

Back 9

Line

Ladder

Pictorial

Front 10

A relay is a device that________

And ________ a set of electrical contacts and is activated by a _____

Back 10

Opens and closes

Coil

Front 11

A contactor works the same way as a relay but is

Back 11

Larger

Front 12

A time delay relay does what

Back 12

Delays the start time of a load

Front 13

A low limit is a NC contact activated by

Back 13

A temperature sensing device

Front 14

An end switch is used to

Back 14

Verify a mechanical action has taken place

Front 15

A flame safeguard system is

Back 15

An electronic system that sequences and supervises burner operation

Front 16

An ignition transformer is

Back 16

A step up transformer used to safely ignite a pilot or main burner by direct spark

Front 17

Main gas valve is piped in _______ and wired in _______

Back 17

Series

Parallel

Front 18

An amplifier is a solid state device that

Back 18

Takes AC current and changes it to DC

Front 19

Low and high level air switches are used to

Back 19

Measure the required air movement through the appliance by measuring a predetermined pressure drop

Front 20

Electrical formulas

E = ?

I = ?

R = ?

W = ?

Back 20

Volts

Amps

Resistance

Watts

Front 21

Ohms law is

Back 21

E = I x R or R = E/I and I = E/R

Front 22

Watts (power) law is

Back 22

W = I x E or P = I x E

Front 23

How many loads are there in a series circuit?

Back 23

One

Front 24

Series circuit resistance ROT

Back 24

The sum of ALL resisters will always be greater than the largest resister in he system

Front 25

Parallel circuit ROT

Back 25

the sum of all resisters will always be LESS than the value of the smallest resister in the system

Front 26

Series circuit formula is

Back 26

Rt = R1 + R2 + R3

Front 27

Parallel circuit formula is

Back 27

1/Rt = 1/R1 + 1/R2 + 1/R3

Front 28

Series/parallel ROT

Back 28

first calculate resistance of parallel circuit and then add the series portion

Front 29

Series/parallel formula

Back 29

1/Rt = 1/R2 + 1/R3

Front 30

VA formula

Back 30

VA = V x A

Front 31

A heat anticipator is designed to prevent

Back 31

System lag and temperature overshoot

Front 32

What gauge wire is used to wire a thermostat

Back 32

18 AWG

Front 33

What do the tsat terminal block labels R W G Y C mean

Back 33

Power

Heating

Fan

Cooling

Common

Front 34

Limit and safety switches are normally _______ switches

Back 34

Closed

Front 35

Flow switches and low water cutoff controls are normally _______ switches

Back 35

Open

Front 36

Limits and safety switches are wired in ________ with the primary control

Back 36

Series

Front 37

A solenoid valve must be upstream or downstream of the 100% shut off valve and the appliance regulator

Back 37

Downstream

Front 38

What is the maximum high limit setting for a forced air conversion furnace

Back 38

250F (120C)

Front 39

What is this symbol

Back 39

Single pole single throw switch

Front 40

What is this symbol

Back 40

Fuse

Front 41

What is this symbol

Back 41

Single pole dbl throw

Front 42

What is this symbol

Back 42

Normally open pressure

Front 43

What is this

Back 43

Normally closed pressure

Front 44

What is this

Back 44

Normally open liquid level switch

Front 45

What is this

Back 45

Normally closed liquid level switch

Front 46

What is this

Back 46

Normally open tstat

Front 47

What is this

Back 47

Normally open fan switch

Front 48

What is this

Back 48

NC high limit

Front 49

Front (Term)

Back 49

NO contact

Front 50

Front (Term)

Back 50

NC contact

Front 51

Front (Term)

Back 51

Magnetic coil

Front 52

Front (Term)

Back 52

Solenoid gas valve

Front 53

Front (Term)

Back 53

Motor

Front 54

What is this

Back 54

Low water cutoff

Front 55

Front (Term)

Back 55

Fixed resister

Front 56

Front (Term)

Back 56

Variable resister

Front 57

Front (Term)

Back 57

Transformer