PARALLELING THE GENERATOR SET (UNITS IN PARALLEL)

Figure 2-15. Stopping Generator Set - Unit Operation

Figure 2-16. Droop Parallel Operation (Sheet 1 of 2)

TM-9-6115-604-12 Generator Set Diesel Engine Driven Tactical Skid Rtd. 60 Kw 3 Phase 4 Wire 120/208 and 240/416 Volts Manual
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ARMY TM 9-6115-604-12 NAVY NAVFC P-8-633-12 2-6. PARALLELING THE GENERATOR SET (UNITS IN PARALLEL). NOTE These procedures assume that one generator set Is on-line (connected to the distribution feeder lines through switchgear). The set that Is to be paralleled shall be designated the "incoming set" Refer to Figure 2-16 through Figure 2-19 for parallel operation, and to Figure 2-20 for removing a generator set from parallel operation When operated In parallel, generator sets must have the same output voltage, frequency, phase relation, and phase sequence before they can be connected to a common distribution bus. Severe damage may occur to the generator sets if these requirements are not met Adjusting engine speed of the Incoming set while observing output frequency, the SYNCHRONIZING LIGHTS, and the SYNCHROSCOPE will bring the phase and frequency into exact agreement. As the phase and frequency approach the same value, the SYNCHRONIZING LIGHTS will gradually turn on and off. When the blinking slows to a rate of once or less per second, close the main circuit breaker of the incoming set while the SYNCHRONIZING LIGHTS are at a point of being dark and the SYNCHROSCOPE is in the 12 o'clock position. Phase sequence has to do with the order in which the generator windings are connected If phase sequence Is not correct, the SYNCHRONIZING LIGHTS will not blink on and off together. CAUTION Should either generator set lose speed, "buck", or "shudder" when the incoming set is connected to the distribution feeder lines, immediately set BREAKER CONTROL switch of incoming set to TRIP and recheck paralleling set-up procedures. When the Incoming set is first connected to the load (through appropriate switchgear) the following may occur if the phase. sequence, voltage, frequency, phase and engine performance are the same, the changeover will be smooth with only the slightest hesitation In engine speed, if each output is slightly out of phase, one of the engines will "shudder" at the point of changeover; if the phase sequence or voltage levels are Incorrect, the reverse power relay will trip on one of the generator sets and open its main circuit breaker contactors, if the Incoming generator set loses speed significantly or almost stalls, the Incoming engine governing system may be defective. 2-7. EMERGENCY STOPPING. a. To stop the generator set from the control room In an emergency, press the EMERGENCY SHUTDOWN pushbutton S7 on engine control cabinet C (3, Figure 2-1). b. To stop the generator set from outside the housing In an emergency, pull out the EMERGENCY SHUTDOWN control In the skid base (Figure 1-1) c. To stop the generator set from the remote control module In an emergency, press the EMERGENCY SHUTDOWN pushbutton S7R (17, Figure 2-21) d. After stopping generator set In accordance with step a or step c, above reset the two air control valves In accordance with Figure 3-21. e. After stopping generator set In accordance with step b, above, reset EMERGENCY SHUTDOWN control In skid base (Figure 1-1). 2-31

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