single phase transformer connection ' Flashcards
When the secondary coils of a 120/240 single-phase transformer are connected in parallel, the transformer will only deliver 240 volts phase to ground.
false
A two-bushing single-phase transformer can be connected to a wye or delta system.
true
A transformer rating of 120/240 shows that there is/are ?
two secondary coils
A transformer’s secondary must be ? when used as part of a 120/208 3-phase bank.
paralleled
When paralleling transformers, both transformers must be connected to the same phases on the primary and on the secondary.
true
When paralleling transformers, the voltmeter must read zero or not over ?
10v
A conventional transformer can be used as a primary booster, but it must be marked as a hazard.
true
If a single-bushing transformer has only one ground and the ground is broken, the tank may become energized at ?
primary voltage
On a single-bushing transformer, the tank ground is ?
also connected of the high voltage winding
One can get 480 volts out of two 120/240-volt transformers by ?
removing the neutral grounding straps, paralleling the primary and connecting the secondary in series
One reason why paralleling two small transformers for increased demand is not economical because ?
cost of transformers
One reason paralleling two small transformers for increased demand is not economical is because the ? , when added together, is/are greater than in one large transformer.
losses of each transformer
If a primary fuse blows on a paralleled transformer, the other transformer will ?
back feed the one with the blown fuse
When paralleling two transformers, the impedance of the two transformers must be within ? and ? of each other.
107.5 / 92.5
When installing a long-term paralleled transformer, the coils must be in series.
false
