Transformer Impedance Table

Approximate Values of Resistance, Reactance, Impedance and X/R Ratios of 600 Volts or Less, 60 Cycles, 3-Phase, Standard Transformers.

(Values in percent on rated kVA as base)
(Primary Voltage - 15 kV or less)

kVA Percent
%Resistance %Reactance %Impedance X R Ratio
DT3    ASL DT3    ASL DT3    ASL DT3    ASL
Liquid Filled, Self-Cooled
  150
  225
  300
  500
  750
1000
1500
2000
2500
1.37
1.57
1.48
1.30
1.28
1.21
1.06
1.00
  .97
3.75
4.21
4.77
4.83
5.60
5.62
5.64
5.66
5.67
4.0  
4.5  
5.0  
5.0  
5.75
5.75
5.75
5.75
5.75
2.74
2.68
3.22
3.71
4.37
4.64
5.32
5.66
5.85
Dry Type, Ventilated
  150
  225
  300
   500
  750
1000
1500
2000
2500
2.5      1.84
2.16    2.04
2.01    2.40
1.65    2.23
1.54    1.94
           1.70
           1.63
           1.63
           1.42
1.26    4.65
4.28    4.57
5.64    4.39
5.77    4.5  
5.8      5.41
           5.49
           5.51
           5.51
           5.57
2.8      5.0  
4.8      5.0  
6.0      5.0  
6.0      5.0  
6.0      5.75
           5.75
           5.75
           5.75
           5.75
  .504   2.53
1.93     2.24
2.8       1.83
3.49     2.02
3.76     2.79
            3.23
            3.42
            3.42
            3.93
Dry Type, Sealed
  300
  500
  750
1000
1500
2000
2500
1.86
1.58
1.32
1.08
1.05
.945
.855
4.64
4.74
5.59
5.64
5.65
5.67
6.18
5.0  
5.0  
5.75
5.75
5.75
5.75
6.25
2.49
3.0  
4.23
5.21
5.38
6.01
7.24



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