Caterpillar — Paralleling Multiple Units
Operation · Generator Set
From a Caterpillar owner's manual covering: 7C-1000, 9Y-1300, 9Y-1400, SR4. Check it applies to your exact model before use.
Applies to: Caterpillar SR4
Procedure
- Start the unit to be parallel according to the procedure in the Engine Operation section.
- Turn the synchronizing lights on.
- After the engine has run a few minutes, bring it up to synchronous speed (the same frequency as the unit on the line); the synchronizing lights will begin to blink.
- Using the governor control, adjust the engine speed until the lights blink very slowly.
- The lights are off when the voltages of the two units are in phase; at this point very quickly close the breaker while the lights are out.
- Use governor controls to share kW load between engines.
- After generator temperature has stabilized (approximately one hour), adjust the droop control of each generator to share the reactive load and limit the circulating currents.
Source: Caterpillar owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.