Ch. 10 * (Power Distribution) Flashcards

0
Q

Matching waveforms

A

“In phase”

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1
Q

Electric shock can cause ___

A

Injury and death

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2
Q

Ohm’s law

A

V = IR

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3
Q

V =

A

Voltage in volts

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4
Q

I =

A

Current in amperes

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5
Q

R =

A

Resistance in ohms

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6
Q

Inductive reactance

A

Magnetic field

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7
Q

Capacitive reactance

A

Electric field

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8
Q

Voltage and current in phase

A

Resistive load

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9
Q

Current lags voltage

A

Inductive circuit

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10
Q

Current leads voltage

A

Capacitive load

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11
Q

Power bill =

A

$99

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12
Q

Watt-Hours

A

Watts X 24 hours X 365 days

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13
Q

1 Watt = ___ BTU/hour

A

3.413

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14
Q

AWG sizing system has become generally accepted ___

A

Worldwide

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15
Q

AWG sizes represent ___

A

Number of steps involved in wire drawing process

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16
Q

AWG size range

A

36 - 4/0

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17
Q

Conductor sizes larger than 4/0

A

Circular Mils

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18
Q

Solid-state equipment generally cause ___

A

Harmonics

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19
Q

Swell

A

Increase

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20
Q

Lag

A

Decrease

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21
Q

The N in N+1 = ___

A

Need

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22
Q

Voltage regulators adjust ___

A

Line voltage

23
Q

Rectifier

A

Battery charger

24
Q

Types of battery cells

A

Except “zinc oxide”

25
Q

Battery room considerations

A

Avoid direct sunlight
Avoid heating/cooling
Near eyewash facility

26
Q

Battery clearance

A

3.28’

27
Q

Optimal battery temperature

A

77°

28
Q

Cell of choice for communications

A

Lead-calcium

29
Q

Most common alkaline cell

A

NiCd

30
Q

Cells can be connected in parallel up to ___ times

A

5

31
Q

Batteries (def.)

A

Store energy and chemical form

32
Q

Aluminum and copper

A

Don’t mix

33
Q

Low voltage disconnect (LVD)

A

Disconnects battery

34
Q

Nominal voltage for telcom in the U.S.

A

-48v

35
Q

Motor generator

A

Utility

36
Q

Engine generator

A

Fuel powered

37
Q

Harmonic filter

A

Reduces voltage

38
Q

Voltage regulator

A

Adjust voltage

39
Q

Best ‘K’ rating for data center

A

K-20

40
Q

K rating =

A

Transformer’s ability to dissipate heat

41
Q

What causes harmonics

A

Solid-state equipment

42
Q

Transients surge

A

Rapid increase

43
Q

Increase in voltage

A

Swell

44
Q

Decrease in voltage

A

Sag

45
Q

Horsepower =

A

Unit of measure for mechanical power

46
Q

12,000 BTU

A

1 ton of air conditioning

47
Q

Ohm’s law formula applies to ___

A

Direct Current (DC)

48
Q

Distribution system

A

Delivery of electricity from utility to customer

49
Q

With DC power, a ___ drop is allowable

A

1 V

50
Q

Available voltages depend on ___

A

Type of transformer

51
Q

Shielded isolation transformers

A

20%

52
Q

It is ___ that voice and data equipment utilize Isolated Grounds

A

Not recommended

53
Q

Output of backup UPS supplies bypass circuit to primary UPS

A

Isolated redundant

54
Q

Formula to calculate power in W

A

Not VR

Not I/R squared

55
Q

Difference between real power (in watts) and apparent power (in volt-amperes)

A

Inductance and capacitance

56
Q

Conducted coupling affects

A

Output/input signal lines and utility/premises electrical power distribution