Generator shuts down; Code 37 displayed indicating voltage imbalance or phase error (3-phase units)

Safety first: Three-phase systems carry dangerous voltages. Open the main breaker, disable auto-start, and use appropriate PPE. Only qualified personnel should work inside the power section.

• Measure phase voltages: With the generator running unloaded, measure voltage between all phase pairs and to neutral (if present). Values should be balanced within manufacturer limits.
• Inspect connections: Tighten all phase lugs and inspect for discoloration or melted insulation indicating overheating.
• Check load balance: Review connected loads in the transfer switch or panel. Redistribute loads to balance current draw across phases.
• Stator and regulator: If one phase is low or missing with good connections, the stator winding or regulator may be faulty and require professional replacement.