MYCHARGEMAN Forum

POWER TRANSFORMER NAME PLATE

The power transformer nameplate will display the model specification. Generally the information available is as follows:

i)       KVA rating                   -This will determine the capacity of the transformer, e.g 300 kVA, 750 kVA, 1000 kVA, etc.

ii)      Rated Voltage     -The voltage between line terminals at high voltage side e.g. 11 kV, 33 kV or low voltage side e.g. 0.415 kV.

iii)     Rated Current     -The current flowing through a line terminal of a winding, derived by dividing the rated power of the winding and by an appropriate phase factor.

iv)     Frequency           -50 Hz or 60 Hz

v)      Phase                             -Three phase system or single-phase system

vi)     Windings             -Delta connected or Star connected windings

vii)    Type of cooling   -Method of cooling either naturally, force or both, e.g ONAN, ONAF, OFAF

viii)   Impedance volt (%)      -The difference between the rated voltage of a winding and the voltage developed at a specified load and power factor, the voltage supplied to the other winding (sec.) being at its rated value.

ix)     Vector group                          - Dy 1 or Dy 11

x)      Core and winding weight      - In kg or metric ton

xi)     Oil weight                               - In kg.

xii)    Oil capacity                                      - In liters or gallons

xiii)   Max temperature rise             - The difference between the temperature of part under consideration and the temperature of cooling air.

xiv)   Tap changer                           - 5 taps or more