A Flashcards
Current rating formula
VA ÷ V
KVA (apparent power) formula
V X A ÷ 1000
Watts in a transformer formula
VA X PF
Volts per turn of wire formula
V/turn = V ÷N
Actual primary voltage % tap formula
Actual primary voltage - rated primary voltage ÷ rated primary voltage
KVA (apparent power) formula
KVA = V X A ÷ 1000
Watts formula
VA X pf
Taps - actual prime voltage formula
Actual prime voltage - rate prime voltage ÷ rated prime voltage
Number of turns formula
V ÷ V / per turn
Each winding lead that is marked with an even number
Should have the same polarity
The relative direction of the transformer prime voltage compared to the direction of its induced secondary voltage
Transformer polarity
If a transformer is constructed so terminal X1 is diaganal from terminal H1
Additive polarity transformer
Transformer constructed so X1 is directly opposite H1
Subtractive polarity transformer
Ways taps can be changed
- manually changing the leads
- moving connecting bars
- installing a mechanical device
5% Full capacity below normal (FCBN)
Used when primary supply voltage is 5% lower than rated voltage