Current limit system and method for electrical discharge machining apparatus

摘要

A programmable system for controlling maximum machining current. A current limit is entered into the system together with the on-time and off-time desired. The system operates to use the desired on-time and current values, but the off-time will be modified depending on the maximum current limit possible. This will protect the apparatus when an impossible combination has been entered by the operator. Minimum allowable period is calculated for any desired current limit. The desired period is subtracted from the minimum period and the difference added to the off-time if the result is positive.