AXLE GP-POWER TRAIN 3W6550 - Caterpillar

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Make final adjustments after paralleled generators have been running at full load for one hour or more. Tighten the locknuts on all controls. Install the access cover. The last condition of 1 has been met. Starting Multiple Units
Multiple units are started the same as single units. Refer to Operation Section, "Single Unit Operation".Paralleling Multiple Units
Units may be paralleled at no load or paralleled with units under load. After the initial start-up conditions are satisfied, verify for the following requirements.
One of the governors can be an isochronous governor. Electronic load sharing governors are an exception.
Generators must have voltage droop compensation or cross current compensation.
Start the unit which will be paralleled.
Turn the synchronizer lights on.
After the engine has run a few minutes, bring the engine up to synchronous speed. This means that the frequency of the incoming unit will be the same as the frequency of the unit on line. The synchronizing lights will begin to blink. Note: The frequency of the incoming unit should be slightly greater than the line frequency. This will allow the incoming unit to assume some of the load rather than add to the system load.
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 in order to share kW load between engines.
Generator temperature will be stabilized in approximately one hour. After the generator temperature has been stabilized, adjust the voltage droop rheostat of each generator in order to share the reactive load and in order to limit the circulating currents. Less droop increases the reactive current that is carried by the generator. Adjusting the voltage droop rheostat in a counterclockwise direction (CCW) will decrease droop. Adjusting the voltage droop rheostat in a clockwise direction (CW) will increase droop. Load Division - Speed Droop (If Equipped)
Once two units have been paralleled, the units share of the kW load is determined by the governor control setting. If two units of the same capacity and the same governor characteristics have the same governor control settings, the units will share the load equally. The total load must not exceed the capacity of the one engine.In order to transfer the load from one engine to another, follow the following procedure.
Increase the governor speed control of one unit in order to increase the load.
Reduce the governor speed control of the other unit in order to decrease the load on that unit.
Raise or lower the governor speed control of both units to change system frequency. Parallel Operation Of Governors
The different governors that can be used on 3500B generator sets are shown below.
Illustration 2 g00630841
Load Sharing Module - typical example
The generator set load sharing module provides either droop load sharing or isochronous load sharing for paralleled generator applications. The load sharing module has a synchronizing parallel module (SPM-A) input. The module provides proportional load sharing. More information is available in the