## Example Transformer Measurements and Calculations

This page has some actual measurements and calculations on GE
Type 5021G10 transformer, which was originally intended for an
illumination power supply for a copier. It has a lot of leakage
reactance to limit the current. The nominal specs are 120V input,
4500V output, 400mA short circuit output current. This
transformer is interesting because it has a third winding,
nominally 600V, for connecting a capacitor for power factor
correction. At rated output, this transformer draws about
8.5Amps, i.e. about 1kVA

Open Circuit Tests

- Primary Voltage: 118V
- Primary Current: 5A
- Active Power to Primary: 69.6W
- Secondary Voltage: 4415

Short Circuit Tests

- Primary Voltage: 68V
- Primary Current: 5A
- Active Power: 40.7W

Calculated:

Reactive Power 585.9 Vars

Magnetizing Circuit R: 200 + j23.76 Ohms

Series equivalent: 1.628+j13.5 Ohms

Copyright 1997, Jim Lux / xfmrex1.htm / Back to transformer
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