Cummins Load Step / Motor Starting Issue

Generator shuts down when large motor loads start (e.g., well pump, AC compressor)

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Generator undersized for motor inrush current, Weak engine performance, Voltage dip causing protective trip, Improper ATS load sequencing

How to Fix / Troubleshooting

Safety first: Work with a qualified electrician when modifying load connections. Disable automatic start before changing wiring.

  • Load analysis: Determine the starting kVA of large motors and compare to the Cummins generator’s motor-starting capability.
  • Stagger starts: Configure the ATS or building controls to start large loads sequentially rather than all at once.
  • Soft starters/VFDs: Consider installing soft starters or variable frequency drives on large motors to reduce inrush.
  • Engine performance: Ensure the engine is properly maintained (filters, fuel, cooling) so it can respond to load steps.
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Repair Difficulty

Medium 3/5

Required Part

Automatic Transfer Switch (ATS)
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