FAQs High Voltage Power & Safety

Why is the short circuit repetition rate of my load set-up important?

How frequently a power supply is short circuited is an important parameter to specify when selecting a supply for a particular application.

As a rule of thumb, most of Spellman's supplies are designed to be short circuited at a 1 Hertz maximum repetition rate. This rating is dictated by the stored energy of the output section of the supply, and the power handling capability of the internal resistive output limiter that limits the peak discharge current during short circuiting. These resistive limiters (that keep the instantaneous discharge current to a limited level) thermally dissipate the stored energy of the supply during short circuiting. If a supply is arced at a repetition rate higher than it was designed for, the resistive limiters in time, may become damaged due to overheating. Brief bursts of intense arcing usually can be handled, as long as the average short circuit rate is maintained at or below 1 Hertz.

Supplies can be modified to enhance their short circuit repetition rate by reducing their internal capacitance and/or augmenting the power handling capability of the resistive output limiting assembly. Please contact the Sales Department for additional information.