€h 10 - Power Distribution Flashcards
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
