Standard ACTL-0750 Accu-CT® models are calibrated for optimum accuracy at 60 Hz. Option 50 Hz calibrates for best accuracy at 50 Hz. Option 50 Hz models have the same accuracy specifications as standard models and are also available in combination with Option C0.6 (selected rated amps) for higher accuracy. In many cases, the accuracy difference between a standard ACTL-0750 and one with Option 50 Hz will be negligible and either could be used at 50 or 60 Hz.

  • The accuracy (at room temperature) of a standard ACTL-0750 used at 50 Hz changes by less than 0.1% in all cases except the ACTL-0750-005 at 1% of rated amps, where the accuracy changes by 0.14%.
  • The phase angle (at room temperature) of a standard ACTL-0750 used at 50 Hz changes by 0.25 to 0.59 degrees (depending on model and load current), with the final phase angle error falling in the range from 0.16 to 0.56 degrees leading.
  • Using an Option 50 Hz model on 60 Hz services would result in similar errors.
  • Over the full rated temperature range (-30°C to 55°C), the worst-case errors will increase somewhat, mostly at temperatures below 0°C.

Test Data

The following table lists standard ACTL-0750 models and typical measurement values when tested at 60 Hz and 50 Hz and at room temperature for accuracy and phase angle (positive phase angles correspond to the CT output voltage leading the measured current). The results show that the accuracy is almost identical at 60 and 50 Hz. They also show that the phase angle changes and becomes somewhat worse at 50 Hz, but is still quite good. For better performance at 50 Hz, order the ACTL-0750 with Option 50 Hz.

Frequency: 60 Hz Frequency: 50 Hz Change from 60 to 50 Hz
ACTL-0750-xxx Model (60 Hz) Current Percent of Fullscale (%) Reading Error (%) Phase (degrees) Reading Error (%) Phase (degrees) Change in Reading Error Change in Phase (degrees)
005 100% 0.12% -0.29 0.12% 0.29 0.00% 0.58
10% 0.07% -0.25 0.09% 0.35 0.02% 0.59
1% 0.24% -0.13 0.10% 0.37 -0.14% 0.50
020 100% 0.02% -0.01 0.02% 0.32 0.00% 0.33
10% 0.00% 0.04 -0.01% 0.38 -0.01% 0.35
1% -0.06% 0.04 -0.06% 0.41 0.00% 0.37
050 100% 0.00% -0.08 -0.02% 0.30 -0.02% 0.38
10% 0.00% 0.07 -0.01% 0.49 -0.01% 0.42
1% -0.04% 0.13 -0.05% 0.56 -0.01% 0.43
100 100% 0.00% -0.03 -0.01% 0.23 -0.01% 0.25
10% -0.02% 0.07 -0.02% 0.34 0.00% 0.27
1% -0.05% 0.12 -0.05% 0.40 0.00% 0.28
200 100% 0.08% -0.10 0.05% 0.17 -0.03% 0.27
10% 0.10% -0.01 0.09% 0.26 -0.01% 0.27
1% 0.06% 0.07 0.07% 0.35 0.01% 0.28
250 100% 0.09% -0.08 0.05% 0.16 -0.03% 0.24
10% 0.10% 0.02 0.10% 0.26 0.00% 0.24
1% 0.08% 0.08 0.08% 0.33 0.00% 0.25

See Also