Catalog No. KATC - Automatic Transformer Comparator


The Knopp KATC Automatic Transformer Comparators (KATC series) provide the most convenient means available to measure instrument transformer ratio and phase angle errors

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This microprocessor-based comparator (KATC) automatically selects the optimum measurement range, computes the results, and digitally displays the test current (or voltage), the transformer ratio and phase angle errors, and the ANSI accuracy class for which the transformer qualifies. Measurement time is greatly reduced, as operator tasks are limited to connection of the transformer-under-test and adjustment of the test current (or voltage). The capability to calculate and display the ANSI accuracy class eliminates the often difficult and time-consuming task of determining whether the measured results fall within the limits of the applicable ANSI parallelogram. The transformer ratio error can be displayed as Percent Error or Ratio Correction Factor. Phase error can be displayed as Minutes or Milliradians.

The comparator circuitry is fully protected and will not be damaged by excessive current (or voltage that may result from improper connection of the transformer-under-test, or from transformers with incorrectly marked ratios. The operator is alerted to such errors by an audible alarm, and is informed of the specific nature of the error by a message on the display.

The comparator can be supplied with the circuitry necessary to interface to a computer for the purpose of test result transfer and storage.

The dimensions and input circuitry allow all previous Knopp comparators, whether in Knopp transformer test systems, or portable, to be easily replaced by the KATC comparators.

Catalog Numbers

  • 36040: KATC-C Automatic Transformer Comparator (Current), 60 Hz
  • 36050: KATC-V Automatic Transformer Comparator (Voltage), 60 Hz
  • 36060: KATC-C Automatic Transformer Comparator (Current), 50/60 Hz
  • 36070: KATC-V Automatic Transformer Comparator (Voltage), 50/60 Hz
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  • Reduced testing time - test results are typically available within three seconds
  • Automatic operation (no manual "nulling" or adjustments required)
  • Microprocessor control
  • Autoranging capability
  • Digital display
  • Calculation and display of ANSI accuracy class
  • Fully protected circuitry
  • RS-232 output
  • Interchangeable with other Knopp comparators


19" wide, 17" deep and 5-1/4" high
45 lbs. (20.4 kg)
Input Power
120 VAC, 0.2A, 50/60 Hz
Test Frequency
60 Hz (50/60 Hz optional)
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