1.
An applied voltage of 10 percent below rating can result in a decrease in efficiency of substantially more than 10 percent — for example, fluorescent light output would be reduced by 15 percent, and incandescent light output would be reduced by __________ . Induction motors would run hotter and produce less torque.
a)
10 percent
b)
30 percent
c)
40 percent
2.
Energy costs can be _________ by decreasing voltage drop.
a)
lowered
b)
eliminated
c)
increased
3.
Article 647 states that for Sensitive Electronic Equipment the voltage drop on branch circuits supplying equipment connected using wiring methods in Chapter 3 shall not exceed _________ and the combined voltage drop of feeder and branch-circuit conductors shall not exceed __________ .
a)
5 percent, 2.5 percent
b)
3 percent, 5 percent
c)
1.5 percent, 2.5 percent
4.
By NEC Article 645 for fire pumps the voltage at the controller line terminals shall not drop more than _________ below normal (controller-rated voltage) under motor starting conditions. The voltage at the motor terminals shall not drop more than _________ below the voltage rating of the motor when the motor is operating at 115 percent of the full-load current rating of the motor.
a)
5 percent, 3 percent
b)
15 percent, 3 percent
c)
15 percent, 5 percent
5.
The energy Code has strict requirements and limits the voltage drop on branch circuits for the run from the final circuit breaker to the outlet or load to _______ maximum voltage drop allowed at design load and limits the voltage drop for the run between the service entrance equipment and the branch circuit distribution equipment to _______ maximum voltage drop allowed at design load.
a)
3 percent, 2 percent
b)
2 percent, 5 percent
c)
5 percent, 4 percent
6.
The effect of a power factor equal to 0.85 for 3 each 3-phase 500 kcmil conductors in a steel raceway increases voltage drop by ____________than the direct current method of calculation.
a)
94 percent more
b)
94 percent less
c)
100 percent more
7.
There are several ways to decrease voltage drop. They include:
a)
using larger size conductors
b)
shortening the circuit length
c)
decreasing the circuit load
d)
for decreasing voltage drop to neutral by balancing the load for 3-phase, 4 wire systems
e)
All of the above
8.
If power factor is not close to 1.0 voltage drop for 3 phase 3 wire circuits in raceway can be found using information from _______ of the NEC.
a)
Table 8
b)
Table 9
c)
Table 10
9.
When we use the direct current method of finding voltage drop we can use the resistances from Table 8 of the NEC or use the following equation: (where L is one way circuit length)
a)
VD = (2KLI/CMA) x multiplier
b)
VD = (KLI/CMA) x multiplier
c)
VD = (KLI/CMA)
10.
By Table 8 of the NEC the resistance of 1000 feet of No. 10 copper stranded conductor is _______ .
a)
1.24 ohms
b)
1.21 ohms
c)
2.04 ohms