AIR CLEANER GP 8N5102 - Caterpillar

of the individual generator amperes exceeds the total amps going to the load by 10% at full load, adjust voltage droop controls to share current proportionally between generators. (Some circulating current is permitted at light load.)
Damage to the generator is possible. Do NOT exceed rated ampere load on any single generator.
8. Make final adjustments after paralleled generators have been running at full load for one hour or more. Tighten the locknuts on all controls and install the access cover. Condition 3 of "Initial Start-up" has been met. Some circulating current is to be expected when generators are cold.Starting Multiple Units
Multiple units are started the same as single units.Paralleling Multiple Units
Units may be paralleled at no load or paralleled with units under load. To parallel two or more units the following conditions must be met:1. Same phase rotation.2. Same voltage level.3. Same voltage droop.4. Same frequency.5. Voltages must be in phase.The first three conditions have been met in the initial start-up for parallel operation.1. Start the unit to be parallel according to the procedure in the Engine Operation section.2. Turn the synchronizer lights on.3. 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.4. Using the governor control adjust the engine speed until the lights blink very slowly. 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.5. 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.6. Use governor controls to share kW load between engines.7. After generator temperature has stabilized (approximately one hour), adjust the droop control of each generator so as to share the reactive load and to limit the circulating currents. Less droop (moving control CCW) increases the reactive current carried by the generator.Load Division - Speed Droop (If Equipped)
Once two units have been paralleled their share of the 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 they will share the load equally.To transfer the load from one engine to the other follow this procedure:The total load must not exceed the capacity of the engine.1. Increase the governor speed control of one unit to increase the load.2. Reduce the governor speed control of the other unit to decrease the load on that unit.3. Raise or lower the governor speed control of both units to change system frequency.Circulating Currents
When two units are paralleled there will be circulating currents. These currents are not doing useful work, but are flowing between the generators. By determining the total generator amperage and subtracting the amperage going to the load, the amount of circulating current can be determined.Circulating currents are caused by voltage