html{display:none} SEL Discharge Surge Suppressor Surge Suppressor | Schweitzer Engineering Laboratories

SEL Discharge Surge Suppressor

Surge Suppressor

Dissipate surges of up to 10 joules where there is a risk of induced voltages in dc cables connecting external devices

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Although the surge suppressor can be used with contact input voltages ranging from 24 Vdc to 220 Vdc, higher contact input voltages require more time for the surge energy to dissipate. Compensate for this time delay by increasing the relay input debounce time setting.


In installations where the dc cable between external devices and the relay is long, there is a risk of induced voltages in the dc cable. Such voltages can discharge into the relay input and result in an incorrect input assertion. The discharge surge suppressor is designed to dissipate surges (such as 1.2/50 µs-type surges [IEEE C62.41.2-2002]) with as much as 10 joules of energy. The maximum charge dissipation capability is that of a 10 µF capacitor charged to 330 Vdc. Packaged into a modular terminal block for easy installation onto any DIN rail, the surge suppressor includes blue markers to distinguish it from regular terminals.

The Firmware IDs for older versions of the firmware can typically be found in Appendix A of the instruction manual.