Transformer Impedance Table. 480 v delta primary to 208y 120 v secondary kva part number enclosure 1 refer to pages 16 27 1 nema type 2 drip proof enclosure. A standard reactances and impedances for ratings 500 kva and below for 60 cycle transformers.
This is important for coordinating over current protection devices. I xfrmr amps primary short circuit kva. Z x rt rated transformer secondary current calculated.
Standard transformers up through 75 kva three.
The impedance is measured in ohms and can include resistance r inductive reactance xl and capacitive reactance xc. I xfrmr amps primary short circuit kva. Where one transformer is larger than the others in the bank use the fault current value for the larger transformer. Table impedances recommended in transformers according to iec formula for the calculation of impedance.
