2-2-4
Distribution transformers normally have one primary coil and ? secondary coil(s). Select one: a.1 b.2 c.3 d.4
B. 2
A transformer that is energized but not loaded can draw as much as ? of the current taken in by a loaded transformer of the same size. Select one: a.1% b.5% c.9% d.10%
B. 5%
Two types of electrical transformer cores are ? . Select one: a.H and core b.shell and basic c.shell and core d.spiral and core
C. Shell and core
Transformer bushings are manufactured using a ? process. Select one: a.cold b.dry c.heat d.wet
D. Wet
Core-type transformers are best suited for low voltage and high currents. Select one: True False
False
Round wire is the only type used in transformer coils. Select one: True False
False
The best insulation for transformer coils is cotton. Select one: True False
False
The high voltage winding is normally placed next to the core to increase EMF. Select one: True False
False
A dry type transformer is cooled by ventilators cut into the metal case. Select one: True False
True
If too small a fuse is used to test a transformer, it may blow due to exciting current. Select one: True False
True
Most distribution transformers are cooled by oil and air. Select one: True False
True
The main purpose of a transformer core is to direct the magnetic flux. Select one: True False
True
The points where high voltage leads are brought out of a coil are considered critical points for insulation. Select one: True False
True
The thin, insulated sheets of steel in a transformer core reduce ? and ? . Select one: a.core loss / heating b.core loss / space c.core loss / weight d.space / heating
a.core loss / heating
Heat in a transformer core is generated because of the ? of molecules. Select one: a.constant drain b.constant reversal c.one-way movement d.presence
b.constant reversal
Normal types of losses concerning electrical transformers are ? . Select one: a.bushing and copper b.copper and core c.core and line d.voltage and current
b.copper and core
Transformer oil must have a ? strength. Select one: a.consistent b.high conductance c.high dielectric d.high viscosity
c.high dielectric
The baked-on insulating compound used in transformer coils prevents ? from getting into the windings. Select one: a.dust and dirt b.eddy currents and moisture c.moisture, dust, and air d.moisture, dust, and dirt
d.moisture, dust, and dirt
More heat flows out of transformer windings if ? or ? wire is used in the coils. Select one: a.aluminum / square b.copper / aluminum c.round / square d.square / rectangular
d.square / rectangular
