Patent ID: 7378821

Claim:
In a method of controlling the input to a three phase inductive load from a three phase AC power supply wherein a measure of reactive power in at least one input line to the load is determined during a time period, and a solid state relay is connected in series in said input line between the power supply and the inductive load and maintained in a non-conducting state for a subsequent period of time, the length of which subsequent period of time is determined by analyzing the measure of VAR, the improvement comprising: analyzing the measure of VAR using a microprocessor dedicated to handling the calculation for said one input line; wherein the measure of reactive power is determined in each of the three input lines to the induction load, the analyzing step for each line performed by a separate microprocessor; wherein the measure of VAR and the analyzing step is conducted during each half cycle of the AC input; and wherein during a half cycle, the VAR for that half cycle is calculated, along with the length of the subsequent period of time during which a solid state relay is to be maintained in the non conducting state during the next like half cycle.