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Flashcards in €h 10 - Power Distribution Deck (53):
1

10-1 Power Distribution

Electrical shock =

 

Cause of injury and death

2

10-4 Phase difference:

Two waveforms match each other in electrical degrees =

 

"In phase"

3

10-7 Distribution

Serving utility and the customer's site =

 

Distribution system

4

10-9 Ohm's Law

V =

(2)

 

* Voltage

* IR

5

10-9 ohms law

I =

(2)

 

* current in amperes

* V/R

6

10-9 ohms law

R =

(2)

* resistance in ohms

* V/I

7

10-9 ohms law

Formulas to calculate power in W =

 

Except W = RV, does not belong

8

10-10 ohms law

Ohms law always applies =

 

(dc)

9

10-10 ohms law

When (V) and (I) are known =

 

Z = sqrt of V/I

10

10-10 ohms law

When (R) and reactance (X) are known =

 

Z = sqrt of (R^2 + X^2)

11

10-10 ohms law

When (R), inductive reactance (XL), and capacitive reactance (XC) are known =

 

Z = sqrt of {R^2 + [X (L) - X (C)]^2}

12

10-10

Inductive reactance =

 

Magnetic

13

10-10

capacitive reactance =

 

Electric

14

Fig 10.9

 

Q image thumb

 

Resistive load

15

Fig 10.10

Q image thumb

 

Inductive circuit

16

Fig 10.11

 

Q image thumb

 

Capacitive load

17

10-13 watt hours

18,500 kWh x 24hrs x 30days = 1332.00 kWh

Cost per usage = $0.075

 

1332.00 kWh x $0.075 = $99

18

10-13 watt hours

2,000 W x 24 hrs x 365days = 17,520,00 watt-hours or kWh

Cost per usage = $0.08 per kWh

 

$0.08 x 17,520 kWh = $1,401.60

19

10-14 Heat

One watt is equal to =

 

3.413 Btu/hr

20

10-14 Heat

Watts x 3.413 =

 

Heat dissipated in Btu

21

10-14 Heat

Btu/12,000 =

 

Tons of air conditioning required to maintain ambient temperature

22

10-14

Horsepower =

 

Unit of mechanical power

23

10-16

AWG =

(2)

 

* American wire gauge

* accepted world wide

24

10-16 AWG numbering system

Sizes in the AWG =

(3)

* Number of steps

* smaller # = larger wire

* larger # = smaller wire

25

10-16 solid conductor range

AWG range =

 

36 AWG to 4/0

26

10-17

circular mils =

 

Larger than 4/0

27

10-20 voltage and current fluctuations

Transients/Surge = 

 

Rapid increase

28

10-20 voltage and current fluctuations

Swell =

 

Increase .05 cycles to one minute

29

10-20 voltage and current fluctuations

Sag =

 

Decrease 0.5 cycles up to one minute

30

10-20 voltage and current fluctuations

Interruption =

 

Total absence

31

10-21 ac voltage quality problems

Solid-state equipment =

 

Cause harmonics

32

10-22 isolated ground (IG)

IG receptacles =

 

Orange triangle

33

10-24 oversized transformers

K-rating =

(2)

 

* Transformer's ability to safely dissipate heat

* Higher k-rating the better the transformer

34

10-31 tier classification N-Base requirement

(N) =

 

Need, or no redundancy

35

10-39 devices that filter/regulate utility lines

Voltage regulators =

 

Adjust the line voltage

36

10-39 devices that filter/regulate utility lines

Harmonic filters =

 

Reduce voltage

37

10-39 generator equipment

Motor generators =

 

Using the utility to drive a motor

38

10-39 generator equipment

Engine generators =

 

Futile-powered engine

39

10-53 direct current (dc) power

Telecommunications the nominal operating voltage =

 

U.S. is -48V

40

10-53 direct current (dc) power

Cellular radio the nominal operating voltage =

 

+24V

41

10-55 dc power

Rectifier/charger =

 

Charges the battery

42

10-56 dc power

LVD =

(2)

* low-voltage disconnect

* disconnect the battery

43

10-65 installation of (dc) systems

Terminating - do not mix aluminum =

 

Copper cable

44

10-66

Batteries =

 

Store energy

45

10-66 Batteries

Three main types of batteries =

* alkaline

* flooded

* valve regulated

* except zinc oxide, does not belong

46

10-66 cells

Cells can be connected in parallel =

 

Increase battery capacity, 5 times

47

10-67 alkaline cells

Common type of alkaline cell =

 

NiCd cell

48

10-67 cells

lead-acid cells =

 

Cell of choice

49

10-67 cells

Gases =

 

A min. of four changes of room air per hour

50

10-73 parallel cells

Five parallel =

 

Not recommended

51

10-73 temperature

Operating temperature of battery =

 

77 degrees

52

10-74

Battery clearance =

 

3.28ft

53

10–75 battery room considerations

Avoid =

 

* exposing the battery plant to direct sunlight

* placing the battery adjacent heating or cooling sources