Kohler — Voltage Check Procedure
Testing & diagnosis · Transfer switch power sources (Source N and Source E)
From a Kohler service manual — check it applies to your exact model before use.
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Before you start
- Testing live electrical circuits. Hazardous voltage or current can cause severe injury or death. Have trained and qualified personnel take diagnostic measurements of live circuits.
- Remove all jewelry, stand on a dry approved electrically insulated mat, and do not touch the enclosure or components inside the enclosure.
Procedure
- If Source N is a generator set, move the generator set master switch to the RUN position; the generator set should start.
- Close the Source N circuit breaker or switch.
- Use a voltmeter to check Source N phase-to-phase and phase-to-neutral (if applicable) terminal voltages and frequency.
- Compare measured values to the transfer switch nameplate; stop installation if the utility voltage and frequency do not match.
- Use a phase rotation meter to check the phase rotation at the Source N (normal) terminals.
- Rewire the Source N terminals to obtain the correct phase sequence if necessary. Default controller phase rotation is ABC.
- If the source is a generator set, stop the generator set by moving the master switch to the OFF position.
- Disconnect Source N by opening upstream circuit breakers or switches.
- Repeat steps 1 through 5 for Source E.
- Disconnect both sources to the transfer switch by opening the circuit breakers or switches.
- Close and lock the transfer switch enclosure door.
- Reconnect both power sources by closing the circuit breakers or switches.
- Move the generator set master switch to the AUTO position.
- Perform the lamp test and then proceed to the automatic operation test.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Source N is the source connected to the normal side of the contactor.
- Source E is the source connected to the emergency side of the contactor.
Source: Kohler service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.