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What is the S811+ Internal Bypass Contactor Voltage Drop?

When the motor is up to speed, the S811+ closes internal (SCR) bypass contactors, also known as shorting contactors. This service to increase the efficiency of the unit, reduce thermal heating of the enclosure, and unload the SCR's during run operation.

If a fault code 13 (FC13) is reported, usually when the STOP command is received by the unit, one or more of the contactors may have failed to pull in at all, or may have failed to seal electrically. 

A higher voltage drop (2 volts or higher depending on mains voltage) across the unit (line to load terminals) when the SCR's are running. If the internal bypass contactor(s) have sealed properly, the voltage drop will be generally less than 0.5 volts.