Card Set Information
for journeyman test
Resistance of copper?
Resistance of Aluminum?
Neutral load of a 3-wire feeder supplied by a 4-wire 3-phase 120/208v or 277/480v wye-connected system formula.
Ln= root of ((L1^2 + L2^2) - (L1 x L2))
In a 230/460v dual-rated motor is what voltage when field windings are connected in series?
Voltage drop permitted for
order of conducters best to worst?
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?
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- 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
one horsepower = ____watts
When doing a feeder service calculation the load demand factor is?
100% for the first 3kva
35% 3001va-120,000 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
Bad beer rots our young guts but vodka goes well
black brown red orange yellow green blue violet gray white
1st band - first number
2nd band- 2nd number
3rd band- multiplie
4th band- tolarance 5%-10%
5th band- quality