
Resistance of copper?
12.9 ohms

Resistance of Aluminum?
21.2 ohms

Neutral load of a 3wire feeder supplied by a 4wire 3phase 120/208v or 277/480v wyeconnected system formula.
Ln= root of ((L1^2 + L2^2)  (L1 x L2))

In a 230/460v dualrated motor is what voltage when field windings are connected in series?
Parellel?

Voltage drop permitted for
Branch circuit?
Entire system?
Feeders?
 branch 3%
 system 5%
 feeders 3%

order of conducters best to worst?
 silver 105%
 copper 100%
 gold 72%
 aluminum 61%

Difference between
Kilowatt (Kw)
Kilovoltampere (Kva)
 Kw = 1000 watts
 indicates the measure of power available for work, indicates real power
 Kva = 1000watts
 indicates the measure of apparent power
 kv=kva when power factor is 1

single phase standard transformer ratings in kva?
 1
 1.5
 2.0
 3.0
 5.0
 7.5
 10
 15
 25
 37.5
 50
 75
 100
 125
 Underlined = also standard 3 phase

def. branch circuit
The circuit conductors between the final overcurrent device protecting the circuit and the outlets

power supplies wired in
parallel?
series?
 parallel Voltage remains the same, current (amp hour for batteries) increases
 series Voltage is added together, current remains the same

Volumes allowence per conductor size?
18, 16, 14, 12, 10, 8, 6
 18 1.5 in^3
 16 1.75
 14 2.00
 12 2.25
 10 2.5
 8 3.00
 6 5.00

one horsepower = ____watts
746 watts

When doing a feeder service calculation the load demand factor is?
 100% for the first 3kva
 35% 3001va120,000 va
 25% 120,001va and up

values of AC?
 Instantaneous value value at any given moment ranging from peak to neg peak
 Peak value effective value /.707
  effective value x 1.414
 Effective value is DC voltage equivalent
 AKA RMS "root mean squared" backwards

Volatge drop formula?
VD = (2 x K x D x I)/cm
Voltage drop = 2 x constant x distance x currant / Circular mills

Resister colors?
 Bad beer rots our young guts but vodka goes well
 black brown red orange yellow green blue violet gray white

risister values?
 1st band  first number
 2nd band 2nd number
 3rd band multiplie
 4th band tolarance 5%10%
 5th band quality

