Electricty Flashcards

1
Q

What do contactors have?

A

Coil
Contacts and mechanical linkage

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2
Q

Contactors are used on

A

Residential Ac and heat pumps

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3
Q

Solenoid flow control flow

A

Gas, water and refrigerant

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4
Q

What is potential difference

A

Measures in volts

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5
Q

Voltmeters measure

A

Potential difference between two specific points

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6
Q

In A/C

A

120V (Hot Black)
240V (Black and red or blue)
Ground is always bare wire or green

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7
Q

Quantity and intensity

A

of electrons moving through a conductor
Is amperage

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8
Q

Coils increase what?

A

Accuracy of ammeter

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9
Q

Reactance is what?

A

Resistance when current is flowing

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10
Q

In inductive reactance, the magnetic Fidel’s forms with current flow

A

And so field from one coil affects the next

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11
Q

Draw Capacitive Reactance Symbol

A
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12
Q

Current Always leads voltage by

A

90

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13
Q

Impedance is what?

A

Sum of all types of resistance

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14
Q

746 watts

A

1 HP

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15
Q

Three phase circuits

A

Each loop 120 degrees apart

Polarity changes 7200

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16
Q

Conductors have 3 or less

A

Electrons

17
Q

Insulators are

A

Materials with 5 or more electrons

18
Q

Circuit breakers

A

Considered as time delayed devices

19
Q

Switches are wired

A

In series with load

20
Q

Transformers have two windings which are?

A

Primary(incoming voltage)
Secondary(outgoing voltage)

21
Q

Solenoid valves (electrically operated)
What type of thing?
Electromagnet coil lift plunger to open or close the valve

A

It is induction

22
Q

What are relays

A

Electromagnetism to operate switch and contacts

23
Q

Contactors are control heavier loads and are

A

Normally open or close

24
Q

Slippage is the difference

A

Between calculated and real speed

25
Q

Split Phase Motor

A

Has run and start

Start Winding determine direction of directions

-disconnects 75% of the rated RPM

26
Q

Symbols for contactors

A

Are shown de-energized (no power)

Normally open

27
Q

Contactors have what elements

A

Coil, contacts, mechanical linkage

28
Q

Contactors start when

A

Coil is energize

29
Q

Contractors are mostly used in residential AC and what

A

Heat pumps

30
Q

What is the first step in troubleshooting a contractor?

A

Chocolate popper voltage
You can also check the mechanical linkage

31
Q

Motors are inductive

A

Heaters are resistive don’t like the number 

32
Q

Current relays are only used on six metering devices so the pressures equalize is equal

A

Compressor is off and starting is easier under low head pressure

33
Q

A start capacitor adds what to the system

A

Starting twerk 

34
Q

The heat bump is a reversible AC unit

A

AC mode it absorbs heat from the inside space injected to the outside and heat pump, mold, absorbs heat from the outside and then rejects it into the inside. Space

35
Q

Heat pump reversing valve determines indoor outdoor coil function and control from the thermostat. What are the four pipe connections?

A

Discharge inlet and suction outlet and two outlets changed from indoor to outdoor coils

36
Q

Draw the cooling and heating on the heat pump visually 

A
37
Q

In cooling mode, the indoor coil absorbs heat, and the outdoor coil reject heat

A
38
Q

In heating mode and the heat pump, the outdoor coil, absorbs heat, and the indoor coil rejects heat

A