Page 102 - Apprentice Manual_Neat

S6-Q137.) Referring to the transfer switch in the figure on the previous page, which control relay(s) operates
with acceptable generator voltage?

a.) *LO
Correct.
b.) SE
Incorrect.
c.) TS
Incorrect.
d.) LO and SE
Incorrect.

S6-Q138.) Which is NOT a transfer switch operator mechanism?

a.) Motor
Incorrect.
b.) Linear motor
Incorrect.
c.) *Hydraulic cylinder
Correct.
d.) Solenoid
Incorrect.

S6-Q139.) How should a transfer switch operate if the utility power is available, it is currently supplying
generator power, and the generator fails?

a.) *Transfer back to utility
Correct. Whenever the utility is available, and the generator fails, the unit should return to the
utility. This will prevent major interruptions in power.
b.) Stay on generator source in case it is restarted
This will cause interruptions in service. If the utility is available, it is always proper to return.
c.)Drop to a neutral position in order not to back-feed either system
This will cause unwanted interruptions when a sound source is available.
d.) Transfer back to utility, but continue to sense for generator restart.
As long as the utility provides power, there is no reason to return to a failed system. Only if the utility
fails should the switch sense for generator start-up.

S6-Q140.) Closed transition of a switch means what?

a.) Break-before-make
This indicates an open transition.
b.) *Make-before-break
Correct. This indicates that the contacts have closed to one circuit before opening the other. A
closed transition.
c.) The switch must close before current may be passed
While this is a true statement, it has nothing to do with transitions.
d.) Any open contacts must be closed before generator start-up to prevent arcing
Closing contacts typically does not cause arcing, opening them does. Second, switches are generally
not closed before start-up to give the generator time to stabilize frequency and voltage.

EGSA Apprentice Certification Program Study Guide - Page 94