Elec Flashcards

1
Q

What are the voltage ratings and colour codes for rubber gloves from class 00 to 2

A
  • class 00: 500V Beige
  • class 0: 1000V Red
  • class 1: 7500V White
  • class 2: 17000V Yellow
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2
Q

What are the 5 emergency procedures after an electrical shock?

A
  1. Remove the victim
  2. Prevent further injury
  3. Send for help
  4. Eliminate the danger
  5. Report the incident
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3
Q

What are ammeters?

A

Inserted in series in a circuit to measure current.

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4
Q

What range of voltages and currents refrigeration mechanics work with?

A

5 VDC - 600 VAC, 20 mA - several hundred Amps

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5
Q

How is ampere expressed as in relation to coulomb

A

I=Q/t

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6
Q

What’s the process of producing EMF by adding heat to 2 dissimilar metals

A

Seebeck Effect

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7
Q

What are thermocouples

A

Thermoelectric generators that change heat into EMF

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8
Q

What are the 6 sources of emf?

A

Magnetic
Chemical
Friction
Heat
Pressure
Light

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9
Q

What current can cause involuntary muscle loss?

A

> 15mA

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10
Q

What are the four factors that affect current on the human body

A

-Area of contact
-Pressure
-Skin resistance
-Point of contact

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11
Q

What are megohmmeters?

A

Used to test electrical insulation resistance by applying a high voltage (>10 kV) typically at 500 VDC with minimum IR of 1 MO

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12
Q

What is Kirchoff’s Current Law?

A

Total current or charge entering a junction is equal to the charge leaving the junction:
I (exiting) + I (entering)=0

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13
Q

What is Kirchhoff’s Voltage law

A

The sum of all voltage drops in a series circuit equals the total applied voltage
E = V¹ + V² + Vn

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14
Q

Phi Φ

A

Magnetic flux

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15
Q

Residual magnetism

A

Ability for a material to remain magnetic after the magnetic force has been removed

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16
Q

Retentivity

A

Ability for a material to retain magnetic qualities after the magnetic force has been removed

17
Q

Factors effecting amount of EMF generated from a generator

A

Amount of magnetic flux, the speed of cutting the lines of force, and length of conductor (number of coiling)

18
Q

In a capacitance circuit, power is consumed by

A

Reactive power

19
Q

In an inductive circuit, power is consumed by

A

Apparent power

20
Q

What’s the unit for reactive power

A

Voltamp reactive, VAR

21
Q

What’s the unit for apparent power

A

Voltamps, VA

22
Q

What’s the unit for capacitance

A

Farad, F

23
Q

What’s the unit for inductance

A

Henry, H

24
Q

What physical properties determines capacitance

A

Size of capacitor (dielectric material, size of electrode plates and the distance between them)

25
Q

What physical properties determines inductance

A

of coils/turns, the core size and material

26
Q

What’s the symbols for apparent power, and reactive power

A

Apparent P: Z
Reactive P: Q