Emergency Diesel Generator Manual Operation test

OPERATING PROCEDURE  of Emergency Diesel Generator

After the engine has started, the controls automatically regulate speed, voltage and frequency. The generator voltage may be adjusted from Remote panel if required. Further speed control is possible from the remote panel, if your facility has one, using the governor switch. After voltage is restored to the under-voltage relay, the diesel engine automatically shuts down after a cool off period of 5-10 minutes, or whatever your setting is. Synchronizing and load pickup may also be tested but this should be done when testing the “Manual” operation mode as described below.

Manual Operation Test (If your facility has Remote capability)

This test should be performed at least once a week. Place the engine mode selector switch at the local control panel in “AUTO” position, to allow manual control from the remote panel. Placing the mode selector switch in the “MANUAL” position defeats all automatic control and causes the engine to start. Therefore, manual start control from the remote panel is only possible with the mode selector switch in “AUTO”. Place the generator feeder circuit breaker switch at the remote panel to the “open” position. Place the “MANUAL-AUTO” switch on the remote panel in the “MANUAL” position. Once the engine starts, the indicating light above the switch will come on indicating the engine is running. Confirmation of engine running can be made by observing the frequency meter on the remote panel or by turning the sync-switch “ON” and observing the “running” voltmeter. To shut down the engine, place the “MANUALAUTO” switch on the remote panel in the “AUTO” position. The engine automatically shuts down after a cool-off period of 5-10 minutes. Unless load pickup or synchronizing testing is desired no other controls on the remote panel should need adjustment.

Load Pickup and Synchronizing Test  (If your facility has Remote capability)

For the most thorough testing possible, you should consider having a load bank test performed by an experienced generator technician on an annual basis. To perform a version of this test yourself instead, the test should be done only during a unit outage since service to essential equipment may be interrupted. The running load in kilowatts on your facility MCC must be known to make this test effective. To begin, make sure the emergency generator main disconnect is “closed”. Start the emergency generator in the “Manual” mode as described above. With the engine running, observe the frequency meter on the remote panel until the meter stabilizes. This ensures the enginegenerator is at a steady-state, no load condition. Place the sync-switch in the “ON” position which enables the Running Voltmeter, Incoming Voltmeter, generator breaker close circuit, and the close circuit of your facility load center or MCC. Observe the Running Voltmeter and adjust the running voltage to equal the voltage shown by the Incoming Voltmeter. Adjust the generator frequency to be just a little faster than the system frequency. When this condition exists, the synchroscope pointer rotates in the clockwise direction. Continue to adjust the generator frequency until the pointer rotates in the clockwise direction at about four revolutions per minute. When incoming and running voltages are matched observe the synchroscope. When the synchroscope indicator is at about 11 o’clock turn generator breaker control switch to “close”.


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