TM 5-3805-258-24-1E N G I N EELECTRICAL SYSTEMThe electrical system has three separate circuits:the charging circuit, the starting circuit and thelighting circuit. Some of the electrical system com-ponents are used in more than one circuit. The bat-tery (batteries), disconnect switch, circuit breaker,ammeter, cables and wires from the battery are allcommon in each of the circuits.The charging circuit is in operation when the en-gine is running. An alternator makes electricity forthe charging circuit. Avoltage regulator in the cir-cuit controls the electrical output to keep the batteryat full charge.CAUTIONThe disconnect switch, if so equipped, must bein the ON position to let the electrical systemfunction. There will be damage to some of thecharging circuit components if the engine isrunning with the disconnect switch in the OFFposition.The starting circuit can operate only after thedisconnect switch is put in the ON position.The starting circuit is in operation only when thestart switch is activated.The low amperage circuit and the charging circuitare both connected through the ammeter. The start-ing circuit is not connected through the ammeter.CHARGING SYSTEM COMPONENTSAlternatorThe alternator is driven by V-type belts from thecrankshaft pulley. This alternator is a three phase,self-rectifying charging unit, and the regulator ispart of the alternator.This alternator design has no need for slip rings orbrushes, and the only part that has movement is therotor assembly. All conductors that carry current arestationary. The conductors are: the field winding,stator windings, six rectifying diodes, and the regula-tor circuit components.The rotor assembly has many magnetic poles likefingers with air space between each opposite pole.The poles have residual magnetism (like permanentmagnets) that produce a small amount of magnet-like lines of force (magnetic field) between the poles.As the rotor assembly begins to turn between thefield winding andS Y S T E M S O P E R A T I O Nthe stator winding, a smallamount of alternating current (AC) is produced inthe stator windings from the small, magnetic lines offorce made by the residual magnetism of the poles.This AC current is changed to direct current (DC)when it passes through the diodes of the rectifierbridge. Most of this current goes to charge the bat-tery and to supply the low amperage circuit, and theremainder is sent on to the field windings. The DCcurrent flow through the field windings (wiresaround an iron core) now increases the strength ofthe magnetic lines of force. These stronger lines offorce now increase the amount of AC current pro-duced in the stator windings. The increased speed ofthe rotor assembly also increases the current andvoltage output of the alternator.The voltage regulator is a solid state (transistor,stationary parts) electronic switch. It feels the vol-tage in the system and switches on and off manytimes a second to control the field current (DC cur-rent to the field windings) for the alternator to makethe needed voltage output.DELCO-REMY ALTERNATOR1. Regulator. 2. Roller bearing. 3. Stator winding. 4. Ballbearing. 5. Rectifier bridge. 6. Fiald winding. 7. Rotoraa-aembly. 8. Fan.STARTING SYSTEM COMPONENTSSolenoidA solenoid is a magnetic switch that does two basicoperations:a. Closes the high current starter motor circuitwith a low current start switch circuit.b. Engages the starter motor pinion with the ringgear.3-18
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