Why is arcing an issue for a high voltage power supply?

Spellman’s high voltage power supplies are designed to tolerate arcing. Individual or intermittent arcing is not problematic; but sustained long term arcing can cause output limiter overheating issues.

Spellman’s high voltage output sections are capacitive by nature. To limit the current that flows during arcing an output limiting circuit is placed in series with the output of the supply. The impedance of this circuit limits the arc current to a safe and predictable level.

The capacitive high voltage output section stores energy where Joules = ½ CV², where C = multiplier capacitance and V = output voltage. This stored energy is dissipated as heat in the output limiter during arcing. Individual or intermittent arcing the heat can be dissipated, but sustained long term arcing can cause overheating of the output limiter.

Some Spellman units have an arc intervention circuit that sense arcing and intervenes on the power supplies behalf to prevent damage due to long sustained long term arcing. Other units do not have arc intervention and sustained long term arcing may cause overheating of the output limiter, permanently damaging the power supply.

If your application has sustained long term arcing, review your requirements with Spellman. We may be able to provide a customized unit with reduced capacitance and/or augmented output limiters to address your high arc rate application.