How to size a Thyristor Power Controller

The formula below provides a simple method to calculate the thyristor current for typical resistive loads. The calculated value of I should then be multiplied by 1.2 (safety margin) to allow for variations in supply voltage and other tolerances of the load.

Single Phase (1PH)

Single Phase (1PH) Thyristor Sizing Tool

Total Load Power W Clear

Line Voltage Vac Clear

Current(I) Amps

Min. suggested Thyristor size Amps

Three Phase (3 or 4 wire load, 2PH or 3PH)

Three Phase (3 or 4 wire load, 2PH or 3PH) Thyristor Sizing Tool

Total Load Power W Clear

Line Voltage Vac Clear

Current(I) Amps

Min. suggested Thyristor size Amps