Standby Generator Sets Engine Protective Devices
ENGINE PROTECTIVE DEVICES
The standby generator may be required to operate for long periods of time without an operator on hand to monitor such engine conditions as coolant tempera- ture, oil pressure or rpm. For that reason, the engine has several devices designed to protect it against potentially damaging conditions by automatically shutting down the unit when the oil pressure is too low, the coolant temperature is too high, the coolant level is too low, or the engine is running too fast.
NOTE:
Engine protective switches and sensors are men- tioned here for the reader’s convenience. Also refer to the applicable control panel manual for additional automatic engine shutdown informa- tion.
HIGH COOLANT TEMPERATURE SWITCH
This switches contacts close if the temperature should exceed approximately 140° C (284° F), initiating an engine shutdown. The generator will automatically restart and the LED will reset once the temperature has returned to a safe operating level.
LOW COOLANT LEVEL SENSOR
Should the engine coolant level drop below the level of the high coolant temperature switch, it is possible for the engine to overheat without automatic shut- down. To prevent such overheating, the engine has a low coolant level sensor. If the level of engine coolant drops below the level of the low coolant level sensor, the engine automatically shuts down.
OVERCRANK SHUTDOWN
After a prespecified duration of cranking, this func- tion ends the cranking if the engine has failed to start. The overcrank LED will turn ON. Turn OFF the AUTO/OFF/MANUAL switch, then turn switch back to AUTO to reset the generator control board.
NOTE:
If the fault is not corrected, the overcrank feature will continue to activate.
Approximate Crank Cycle Times
•15 seconds ON
•7 seconds OFF
•7 seconds ON
•7 seconds OFF
•Repeat for 45 seconds Approximately 90 seconds total.
OVERSPEED SHUTDOWN
A speed circuit controls engine cranking,
RPM SENSOR LOSS SHUTDOWN
If the speed signal to the control panel is lost, engine shutdown will occur.
LOW OIL PRESSURE SWITCH
This switch has normally closed contacts that are held open by engine oil pressure during cranking and operating. Should oil pressure drop below the 8 psi range, switch contacts close, and the engine shuts down. The unit should not be restarted until oil is added, and the AUTO/OFF/MANUAL switch must be turned to OFF and then back to AUTO.
DC FUSE
This fuse is located inside of the control panel. It protects the panel wiring and components from damaging overload. Always remove this fuse before commencing work on the generator. The unit will not start or crank if the fuse is blown. Replace the fuse with one of the same size, type, and rating. (See the exploded views and parts lists at the end of this manual for replacement part number.)
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