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TABLE 4-33. REVERSE POWER (335)

Many troubleshooting procedures present hazards that can result in severe personal injury or death. Only qualified service personnel with knowledge of fuels, electricity, and machinerhazards should perform service procedures. Review safety precautions on pages iii and iv.

Indicator(s) Possible Cause Corrective Action

REVERSEPOWERshutdown(335)message.

*CAUTION: Wearing wrist strap, set S12 to Off and A32 S5 to Standby before connecting/disconnecting harness plugs.

1. If this shutdown condition occurswhen a non-paralleled generatorset is loaded, it indicates that thegenerator set output CTs or PTsare incorrectly installed.

1. Verify proper CT orientation, wiring andconnections on the control system. Refer toCurrent Transformer (CT) Installation inSection 5. Make sure that the no load fre-quency matches the bus frequency. Checkmetering calibration for both generator setand bus.

2. Verify that the generator set is op-erating at the correct frequencyand voltage. The bus voltage and

frequency should be the same asthe no-load generator set frequen-cy and voltage.

2. Make adjustments as required for properoperation.

3. The load sharing line connectionsand orientation must be correctlyaccomplished for proper load shar-ing.

3. Verify that load sharing connections aremade as noted in the drawings and thatthere are no damaged or disconnectedwires.

4. If the alarm occurs when a largeload is added or shed, dissimilartransient response of the genera-

tor sets in the system may causethe reverse power condition.

4. Apply various load steps to each generatorset in the system, noting the voltage andfrequency dips/surges and recovery times.

The generator sets should be adjusted sothat transient load performance is approxi-mately the same in all machines in the sys-tem.

5. Reverse power alarm can also in-dicate that the generator set is un-able to carry load properly.

5. Verify that the generator set can pick upand carry loads properly, up to the rated ca-pacity of the machine. Inability to carry loadcan be related to engine misadjustments,component failures, or poor fuel quality.Check governing system for binding orsticking. Check fuel filters and fuel lines for

cracks, leaks or dents. Check air cleaner(s)for obstructions.

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