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
Types of battery cells
Except "zinc oxide"
25
Battery room considerations
Avoid direct sunlight Avoid heating/cooling Near eyewash facility
26
Battery clearance
3.28'
27
Optimal battery temperature
77°
28
Cell of choice for communications
Lead-calcium
29
Most common alkaline cell
NiCd
30
Cells can be connected in parallel up to ___ times
5
31
Batteries (def.)
Store energy and chemical form
32
Aluminum and copper
Don't mix
33
Low voltage disconnect (LVD)
Disconnects battery
34
Nominal voltage for telcom in the U.S.
-48v
35
Motor generator
Utility
36
Engine generator
Fuel powered
37
Harmonic filter
Reduces voltage
38
Voltage regulator
Adjust voltage
39
Best 'K' rating for data center
K-20
40
K rating =
Transformer's ability to dissipate heat
41
What causes harmonics
Solid-state equipment
42
Transients surge
Rapid increase
43
Increase in voltage
Swell
44
Decrease in voltage
Sag
45
Horsepower =
Unit of measure for mechanical power
46
12,000 BTU
1 ton of air conditioning
47
Ohm's law formula applies to ___
Direct Current (DC)
48
Distribution system
Delivery of electricity from utility to customer
49
With DC power, a ___ drop is allowable
1 V
50
Available voltages depend on ___
Type of transformer
51
Shielded isolation transformers
20%
52
It is ___ that voice and data equipment utilize Isolated Grounds
Not recommended
53
Output of backup UPS supplies bypass circuit to primary UPS
Isolated redundant
54
Formula to calculate power in W
Not VR | Not I/R squared
55
Difference between real power (in watts) and apparent power (in volt-amperes)
Inductance and capacitance
56
Conducted coupling affects
Output/input signal lines and utility/premises electrical power distribution