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Electrical > Electrical > Flashcards

Electrical Flashcards

1
Q

During a power outage a thermopile/powerpile equipped burner in a convection type appliance (space or wall heater) will…

A

Continue to operate normally

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2
Q

*An open circuit test for a thermocouple should read

A

A maximum of 30 mvdc and a minimum of 20 mvdc

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3
Q

Minimum operating voltage of a thermocouple before replacing it is…

A

8 mvdc

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4
Q

A reading of 10-15mvdc across a closed switch on a powerpile system may indicate…

A

Switch contact is in poor condition

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5
Q

A millivolt system, using 16 gauge wire can have a maximum length of…

A

50 feet

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6
Q

Drop out reading of 10 millivolts or more indicates…

A

Defective pilot stat in gas valve

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7
Q

Thermocouple tip should be inserted into the pilot flame…

A

3/8 - 1/2 inch

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8
Q

Noisy or lifting pilot flame indicates

A

High gas pressure

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9
Q

Millivolt wiring can’t run near line voltage wiring since…

A

Line voltage wiring will induce a voltage into millivolt wiring

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10
Q

A thermostat for millivolt systems is rated in

A

0-1.5 VDC

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11
Q

3 voltage outputs for a thermopile/powerpile

A

250, 500, 750 MV

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12
Q

Transformers power output(s)

A

VA and Watts

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13
Q

What does a transformer consist of?

A

Core of iron plates, primary and secondary winding

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14
Q

Best type of connection for millivolt systems

A

Soldered connections

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15
Q

Motor starting switch rated in…

A

Horsepower

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16
Q

Temperature difference needed between hot and cold junction

A

400 Farenheit

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17
Q

Pilot stat test operation depends on two tests

A

5 to 2 mvdc, 90 seconds

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18
Q

Another thing to do

A

Go over reading diagrams

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19
Q

Electrical service is rated in

A

Amps

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20
Q

Minimum electrical service to a new residential building

A

100 Amps

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21
Q

Electrical distribution system consists of:

A

Electric meter, main disconnect, distribution panel

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22
Q

What protection does a 240 volt circuit need in the distribution panel?

A

Double pole breaker

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23
Q

Overload protection for a 120 volt circuit in the distribution panel

A

Single pole breaker

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24
Q

GFI is required in…

A

Wet locations

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25
Q

When is gas piping bonded?

A

To prevent arcing or sparks

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26
Q

Ultimate purpose of a fuse or circuit breaker in the distribution system

A

To protect higher amperage from damaging electrical conductors

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27
Q

Circuits powering a motor that is protected by a plug fuse, shall use a

A

Type P

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28
Q

Electrical conductors are made in

A

Solid, stranded wire

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29
Q

*Allowable amperage in a circuit using No.14/3 AWG Wire at 60 Degrees Celsius

A

20 Amps

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30
Q

NMD stands for…

A

Non-metallic dry

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31
Q

NMW stands for…

A

Non-metallic wet

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32
Q

Maximum allowable amperage using #10 AWG wire

A

30 Amps

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33
Q

White wire indicates

A

Neutral conductor

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34
Q

Wire exposed to mechanical damage must be

A

AC (BX)

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35
Q

The lower the gauge wire

A

The more current the conductor can safely carry

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36
Q

Types of wiring diagrams in the gas industry

A

Pictoral, schematic, connection

37
Q

Where does the circuit breaker in a 120v circuit supply power from?

A

Load side of the main breaker

38
Q

Maximum amperage of a fuse in a distribution panel is limited by

A

Gauge of the wire

39
Q

Armoured cable is

A

BX

40
Q

Motor circuit protection fuse is a

A

Time delay fuse

41
Q

Where does the 240v supply for an electric range come from last

A

Load side of a double branch breaker

42
Q

Schematic diagrams show components

A

Normally de-energized

43
Q

Direct current travels

A

In one direction forward

44
Q

Line and load sides for the disconnect/service switch use what colour for residential furnaces

A

Both black wires

45
Q

Electrical conductors when subjected to higher temperatures

A

Results in lower resistance

46
Q

Unit of measure for EMF

A

Volts

47
Q

Fuses and breakers protect

A

Wires

48
Q

Max amps for 12 AWG

A

20 Amps

49
Q

Diameter of wire goes up

A

Resistance goes down

50
Q

Voltage measured in residential distribution system

A

240v

51
Q

3 operating controls

A

Thermostat, operating aquastat, operating pressure controls

52
Q

3 safety controls

A

High-limit switch, pressure switch, flow switch

53
Q

3 types of pilots in a residential furnace

A

Standing, intermittent, hot surface igniter

54
Q

3 main types of automatic ignition control systems in a residential furnace

A

Intermittent pilot, direct spark ignition, hot surface ignition

55
Q

3 main components in a combination gas valve

A

Gas control valve, pressure regulator, pilot

56
Q

Another name for an air flow switch

A

Sale switch

57
Q

Minimum ratio of ground surface area to flame rod surface area for proper flame rectification

A

4-1

58
Q

Advantage of a redundant gas valve

A

Higher safety (second shut-off valve is incorporated) Eliminates the

59
Q

Safety device used on all storage type water heaters

A

Temperature and pressure relief valve

60
Q

3 types of gas pressure regulators

A

Line pressure regulator, appliance regulator, service regulator

61
Q

Sequence of operation for CAT 1 Fan Assist Furnace with D.C

A

Call for Heat, inducer Motor Start, Pressure Switch Check, Ignition Sequence, Flame Sensing, Main Burner Operation, Blower Motor Activation, Thermostat Satisfaction

62
Q

Basic operation of ignition system

A

Perform safety check, ignite the flame, powering gas valve, proving flame, monitor flame

63
Q

SRC, TRIAC, and DIAC are

A

Thyristors

64
Q

Primary difference between a relay and contactor

A

Relay for lower power application, contactor for higher power applications

65
Q

Relay operates by

A

Electromagnetic coil

66
Q

Thermocouple MV range

A

0-30

67
Q

Millivolt - Volt

A

1/1000

68
Q

Thermopile MV range

A

Up to 750 mv

69
Q

Open circuit thermocouple test

A

Should read 30 mv, below 20 mv must be replaced

70
Q

Closed circuit thermocouple test

A

Should read 15 mv, below 8 mv must be replaced

71
Q

Pilotstat coil MV reading

A

Under normal operation 10-15 mv, must hold the valve open until 5-2 mv

72
Q

750 mv thermopile must power…

A

Control circuit and combustion safety circuit in parallel

73
Q

30 ft = AWG

A

18 Min.

74
Q

50 ft = AWG

A

16 min.

75
Q

80 ft = AWG

A

14 min.

76
Q

Thermopile = How many thermocouples

A

10-30

77
Q

Thermocouples = Which pilot?

A

Standing

78
Q

Type of current for thermocouples

A

DC

79
Q

Thermostat:
R= 24v power
W= Heating
Y= Cooling
G= Fan
C = 24v Common

A

YEaaaaaa

80
Q

Where would you find an operating pressuretrol?

A

Hot water boiler

81
Q

Operating pressuretrol responds to changes in

A

Steam pressure

82
Q

Heat anticipator is wired

A

In series w the gas valve

83
Q

HIgh gas pressure switch opens when pressure is exceeded by

A

25%

84
Q

When heated, ignites burners in a furnace

A

Hot surface igniter

85
Q

Unitrol is used on

A

Water heater

86
Q

Flame rod is made of

A

Kanthol

87
Q

Valve for throttling fluid

A

Globe valve

88
Q

Redundant gas valve contains

A

2 automatic gas shut off valves in series

89
Q

Rod and tube is made of

A

Invar

Electrical (2 decks)

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