Transformer Calibration Tester Calibration Procedure

Current and Voltage Transformer Load Box Application

The voltage transformer load box is connected between the 'a' and 'x' terminals of the tested voltage transformer during use.

2. The load box for current transformers is connected in series between the K2 of the tested current transformer and the TX of the calibration instrument during use.

3. Adjust the load to the actual secondary load of the test transformer.

Note: The secondary load of some current transformers is expressed in terms of capacity, measured in VA.

The load of a current transformer's load box is generally represented by the resistance value, with the unit being... Their conversion relationship is:

Capacity (VA) = Resistance (Ω) Secondary Current (A) Secondary Current (A)

4. Important Notes:

(1) Customized load boxes with special requirements are available upon customer request.

(2) The current load box, excluding the external conductor resistance of 0.06 (or 0.05), refers to the resistance of the connecting conductors in addition to the load resistance of the test transformer when the load box is actually in use. If cosφ = 1, the actual resistance of the load box is 0.4 - 0.06 = 0.34; if cosφ = 0.8, the actual resistance R = 0.4 * 0.8 - 0.06 = 0.26, and the reactance X = 0.4 * 0.6 = 0.24.