On three-phase Kohler standby generators, controller displays “Loss of Phase” or “Phase Failure”; some loads lose power.

Safety first: Turn generator OFF, open main breaker, lock out/tag out the transfer switch, and verify absence of voltage with a meter before touching conductors.

• Inspect lugs: Tighten all phase and neutral lugs at the generator output and in the transfer switch. Look for discoloration or melted insulation indicating overheating.
• Check breakers: Verify that any individual phase breakers or fuses are not tripped or blown. Replace defective devices.
• Continuity test: With power off, test continuity of each phase conductor from generator to transfer switch to ensure no open circuits.
• Alternator test: With a qualified technician, run the generator and measure voltage on each phase. If one phase is low or zero with good wiring, the alternator winding may be damaged.

Phase loss can damage three-phase motors. If alternator damage is suspected, contact a Kohler-authorized service center.