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Overspeed

Why generators show "overspeed": 3 documented causes and brand-specific fixes, compiled across 7 manufacturers.

Defined as 120% of rated speed for engines rated from 1470 through 2600 rpm, and 110% of rated speed for engines rated from 2800 through 3000 rpm.

1 brand
  • Clarke: Investigate the cause and make necessary corrections before placing engine back in service. The OVERSPEED RESET BUTTON must be pressed to reset.

Battle Short mode is suspended and a shutdown occurs immediately

1 brand

Operation of overspeed switch (S5)

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Affected models

Cummins/Onan 100 DGDBCummins/Onan 100GGHHCummins/Onan 1100DFLBCummins/Onan 1120 DFLCCummins/Onan 1250DFLCCummins/Onan 125GGHJCummins/Onan 125GGLACummins/Onan 1290DFLECummins/Onan 140GGLBCummins/Onan 1500DFLECummins/Onan 150GGLBCummins/Onan 275DQHAACummins/Onan 300 DQHAB

Related fault codes

Cummins/Onan fault codesKohler fault codesOnan Modified Ford V-10 fault codes

Common questions

What causes overspeed?

Common causes, most-reported first: Defined as 120% of rated speed for engines rated from 1470 through 2600 rpm, and 110% of rated speed for engines rated from 2800 through 3000 rpm.; Battle Short mode is suspended and a shutdown occurs immediately; Operation of overspeed switch (S5).