802928 Mercruiser FITTING, Thru-Hull

Illustration 1 g01432420
Electrical circuit (1) Air inlet heater (2) Indicator (3) Relay (4) Relay (5) Alternator (6) Pilot light for battery charge (7) Switch for starting motor (8) Starting motor (9) Battery (A) 1 gauge wire (B) 6 gauge wire (C) 18 gauge wireThe electrical system has three separate circuits: charging circuit, starting circuit and low amperage circuit. Some of the components of the electrical system are used in more than one circuit. The following items are common in each of the circuits: battery, circuit breaker, ammeter (not shown), cables and wires from the battery.The charging circuit is in operation when the engine is running. Alternator (5) makes electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output in order to keep the battery at full charge.The starting circuit is in operation only when the start switch is activated.The low amperage circuit is connected through the ammeter and the charging circuit is connected through the ammeter.Grounding Practices
Proper grounding for the vehicle system is necessary for proper vehicle performance and reliability. Proper grounding for the electrical system is necessary for proper machine performance and reliability. Improper grounding will result in uncontrolled electrical circuit paths and improper grounding will result in unreliable electrical circuit paths. Damage to main bearing and damage to the crankshaft bearing journal surfaces can occur. Uncontrolled electrical circuit paths can also cause electrical noise which may degrade machine performance.Use an engine-to-frame ground strap. The engine-to-frame ground strap must have a direct path to the battery. The direct path will ensure proper functioning of the machine electrical system. The direct path will also ensure proper functioning of the engine electrical system. Use a frame to starting motor ground or use a frame to engine ground.Ground wires should be combined at ground studs. The ground studs should be dedicated for ground use only. The engine alternator must be grounded to the negative terminal of the battery. The size of ground wire must be adequate to handle a full current for charging the alternator.
This engine has a 24 Volt starting system.Use only the same voltage (24 volts) for jump starting. Use of a welder or higher voltage will damage the electrical system.
Charging System Components
Alternator
Illustration 2 g01383972
Typical alternator components (10) Voltage regulator (11) Bearing (12) Stator winding (13) Bearing (14) Rectifier bridge (15) Field winding (16) Rotor assembly (17) Fan
The alternator should never be operated without the battery in the circuit. The making or the breaking of an alternator connection with a heavy load on the circuit can cause damage to the regulator.
The alternator is driven by a belt from the pulley of the crankshaft. The alternator is three-phase and the alternator is a self-rectifying charging unit. The voltage regulator is part of the alternator.The alternator does not need slip rings and the alternator does not need brushes. The rotator assembly is the only part in the alternator that moves. The conductors that carry current are stationary. The following items are conductors: wiring, stator windings, six rectifying diodes and components of the regulator circuit.The rotor assembly has many magnetic poles. An air space is between the opposite poles. The poles have residual magnetism that produces a small magnetic field between the poles. Residual magnetism is similar to permanent magnets. As the rotor assembly begins to turn between the field winding and the stator windings, a small amount of alternating current (AC) is produced in the stator windings. The small amount of current is produced from the small magnetic lines of force. The small magnetic lines of force are made by the residual magnetism of the poles. The alternating current passes through the diodes of the rectifier bridge and the alternating current is then converted into direct current (DC).The current primarily charges the battery and the current primarily supplies the low amperage circuit. The remainder of the current is sent to the field windings (wires around an iron core). This increases the strength of the magnetic lines of force. The amount of alternating current that is produced in the stator windings increases. The increased speed of the rotor assembly increases the current output of the alternator. The increased speed of the rotor assembly also increases the voltage output of the alternator.The voltage regulator is an electronic switch. The voltage regulator consists of a transistor and stationary parts. The voltage regulator turns on and the voltage regulator turns off in order to control the field current (DC current to the field windings) for the alternator.Starting System Components
Electric Starting Motor
Illustration 3 g01383978
Components of the starting motor (18) Solenoid (19) Pinion (20) Reduction gear (21) Overrunning clutchThe starting motor has gear reduction. The starting motor is provided with a one-way roller clutch. Major components of the starting motor include the following items: motor, overrunning clutch (21) and solenoid (18) . The motor generates power. The overrunning clutch transmits torque of the armature. The overrunning clutch also limits the engine rpm after start-up. Solenoid (18) engages pinion (19) with the flywheel ring gear. Reduction gear (20) reduces the speeds of the armature and the reduction gear transmits torque to the pinion.Reduction Gear
Illustration 4 g01383983
Assembly of reduction gear (22) Armature shaft (23) Pinion (24) Overrunning clutchThe end of armature shaft (22) has a gear. The gear engages with an internal gear. The reduction gear reduces high motor speed. The reduction gear also transmits higher cranking torque to the pinion shaft.Overrunning Clutch
Illustration 5 g01383987
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