10-1 Power Distribution

Electrical shock =

Cause of injury and death

10-4 Phase difference:

Two waveforms match each other in electrical degrees =

"In phase"

10-7 Distribution

Serving utility and the customer's site =

Distribution system

10-9 Ohm's Law

V =

(2)

* Voltage

* IR

10-9 ohms law

I =

(2)

* current in amperes

* V/R

10-9 ohms law

R =

(2)

* resistance in ohms

* V/I

10-9 ohms law

Formulas to calculate power in W =

Except W = RV, does not belong

10-10 ohms law

Ohms law always applies =

(dc)

10-10 ohms law

When (V) and (I) are known =

Z = sqrt of V/I

10-10 ohms law

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

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

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}

10-10

Inductive reactance =

Magnetic

10-10

capacitive reactance =

Electric

Fig 10.9

Resistive load

Fig 10.10

Inductive circuit

Fig 10.11

Capacitive load

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

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

10-14 Heat

One watt is equal to =

3.413 Btu/hr

10-14 Heat

Watts x 3.413 =

Heat dissipated in Btu

10-14 Heat

Btu/12,000 =

Tons of air conditioning required to maintain ambient temperature

10-14

Horsepower =

Unit of mechanical power

10-16

AWG =

(2)

* American wire gauge

* accepted world wide

10-16 AWG numbering system

Sizes in the AWG =

(3)

* Number of steps

* smaller # = larger wire

* larger # = smaller wire

10-16 solid conductor range

AWG range =

36 AWG to 4/0

10-17

circular mils =

Larger than 4/0

10-20 voltage and current fluctuations

Transients/Surge =

Rapid increase

10-20 voltage and current fluctuations

Swell =

Increase .05 cycles to one minute

10-20 voltage and current fluctuations

Sag =

Decrease 0.5 cycles up to one minute

10-20 voltage and current fluctuations

Interruption =

Total absence

10-21 ac voltage quality problems

Solid-state equipment =

Cause harmonics

10-22 isolated ground (IG)

IG receptacles =

Orange triangle

10-24 oversized transformers

K-rating =

(2)

* Transformer's ability to safely dissipate heat

* Higher k-rating the better the transformer

10-31 tier classification N-Base requirement

(N) =

Need, or no redundancy

10-39 devices that filter/regulate utility lines

Voltage regulators =

Adjust the line voltage

10-39 devices that filter/regulate utility lines

Harmonic filters =

Reduce voltage

10-39 generator equipment

Motor generators =

Using the utility to drive a motor

10-39 generator equipment

Engine generators =

Futile-powered engine

10-53 direct current (dc) power

Telecommunications the nominal operating voltage =

U.S. is -48V

10-53 direct current (dc) power

Cellular radio the nominal operating voltage =

+24V

10-55 dc power

Rectifier/charger =

Charges the battery

10-56 dc power

LVD =

(2)

* low-voltage disconnect

* disconnect the battery

10-65 installation of (dc) systems

Terminating - do not mix aluminum =

Copper cable

10-66

Batteries =

Store energy

10-66 Batteries

Three main types of batteries =

* alkaline

* flooded

* valve regulated

* **except zinc oxide, does not belong**

10-66 cells

Cells can be connected in parallel =

Increase battery capacity, 5 times

10-67 alkaline cells

Common type of alkaline cell =

NiCd cell

10-67 cells

lead-acid cells =

Cell of choice

10-67 cells

Gases =

A min. of four changes of room air per hour

10-73 parallel cells

Five parallel =

Not recommended

10-73 temperature

Operating temperature of battery =

77 degrees

10-74

Battery clearance =

3.28ft

10–75 battery room considerations

Avoid =

* exposing the battery plant to direct sunlight

* placing the battery adjacent heating or cooling sources