TM 9-6115-604-34NAVFAC P8-633-34SECTION VI. ELECTRIC GOVERNOR SYSTEM6-22. GENERAL. The electric governor system is an electrical sensing system that maintains precise control of enginespeed at any selected point, and provides rapid transient response to load changes. It is all electric and requires noengine drive or hydraulic system. It is ruggedly built to resist vibration and physical damage. The governor system isdesigned to provide steady state speed stability of less than plus or minus 0.25 percent, generally referred to asisochronous regulation. Droop can be obtained with a simple jumper connection at the control panel terminal block. Theelectric governor system consists of a magnetic pickup PUl (mounted in the engine flywheel housing), an actuator L101(mounted on the fuel pump and electrically linked to the electric governor control unit), and a load sharing panel A104(mounted inside cabinet B). The load sharing panel A104 is comprised of the electric governor control, a 50/60 Hzmodule, and a precise load sharing module.a.Actuator.(1)The actuator Li 01 is an electromagnetic rotary solenoid valve mounted in the PT (Type G) VS-EFC fuelpump. By regulating fuel pressure and hence fuel flow into the injectors, the actuator Li 01 determinesengine speed and horsepower.(2)The actuator Li 01 is controlled by the electric governor control unit which senses electrical signalsproportional to actual engine speed from a magnetic pickup PUl, mounted on the engine flywheel housing.(3)The electric governor control unit compares this feed back signal (engine speed and any speed variationsbrought about by load changes) against predetermined speed control reference set points and providescompensating current signals which turn the actuator shaft to either increase or decrease fuel pressure inorder to maintain the preselected engine speed regardless of load changes.(4)Anytime the load is increased, the engine slows down causing a decrease in frequency signal from themagnetic pickup PUl. This signal change is picked up by the electric governor control unit which thendrives the actuator shaft to increase fuel pressure until the engine is brought back to the preselectedspeed.(5)Refer to paragraph 6-9 for testing, removal, or replacement of the actuator.b.Magnetic Pickup PUl.(1)The magnetic pickup PUl is a magnetic device that is mounted in the flywheel housing. As the flywheelgear teeth pass the pickup, an ac voltage is induced, one cycle for each tooth. The frequency input signalfrom the magnetic pickup PUl may be as low as 0.5 volt rms or as high as 30 volts rms. A value of 1 voltrms at cranking speed is adequate.(2)The magnetic pickup PUI is mounted through a threaded hole in the gear case of the flywheel bell housing.The magnetic pickup PU 1 can be screwed in (with engine stopped) until the tip strikes the top of the geartooth, then backed out three-quarters of a turn and secured by the locknut.c.Battery Voltage Input. The input battery voltage is 24 V dc (do not connect to a battery charger). All circuits areisolated from the case; therefore, no ground is required. The maximum input current for 24 volts isapproximately 3 amperes.d.Load Sharing Panel A104 (see Figure 6-30).(1) The load sharing panel A104 consists of three components:(a)An electric governor control unit for engine speed control.(b)A precise load-sharing module for load sharing of two or more engines.(c)A 50/60 Hz module which permits the engine to operate generator G1 at 50 or 60 cycle operatingoutput. This module contains two frequency trim adjustments.(2)The load sharing panel A104 will provide accurate control at temperatures from -65 to 175F (-54 to 79C).The power resistors on the load sharing module will develop some heat which must be dissipated.(3) The three load sharing panel A104 components are prewired into the top row of the 30-position terminalstrip.6-57
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