874304 Volvo.Penta Starter motor

When jump starting an engine, the instructions in the Operation and Maintenance Manual, "Starting with Jump Start Cables" should be followed in order to properly start the engine.This engine may be equipped with a 12 volt starting system or with a 24 volt starting system. Only equal voltage for boost starting should be used. The use of a welder or of a higher voltage will damage the electrical system.
This engine is tolerant to common external sources of electrical noise. A buzzer that uses electrical energy can cause disruptions in the power supply. If a buzzer is used anywhere on the machine, the engine electronics should be powered directly from the battery system through a dedicated relay. The engine electronics should not be powered through a common power bus with other key switch activated devices.Engine Electrical System
The electrical system has the following separate circuits:
Charging
Starting
Low amperageSome of the electrical system components are used in more than one circuit. The following components are common in more than one circuit:
Battery or batteries
Circuit breakers
Battery cables
Wires from the battery
Ammeter
Disconnect switchIn order for the electrical system to operate properly, the disconnect switch must be in the ON position. Damage will occur to the charging system, if the engine is operating with the disconnect switch in the OFF position.The starting circuit can operate only with the disconnect switch in the ON position.The charging circuit is in operation when the engine is running. An alternator 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 and the charging circuit are connected through the ammeter. The starting circuit is not connected through the ammeter. Charging System Components
Alternator
The alternator is driven by a belt from the crankshaft pulley. This alternator is a three-phase, self-rectifying charging unit, and the regulator is part of the alternator. The alternator design has no need for slip rings or brushes, and the only part that has movement is the rotor assembly. All conductors that carry current are stationary. The following conductors are in the circuit:
Field winding
Stator windings
Six rectifying diodes
Regulator circuit componentsThe rotor assembly has many magnetic poles that look like fingers with air space between each of the opposite poles. The poles have residual magnetism. The residual magnetism produces a small magnetic field between the poles. As the rotor assembly begins to turn between the field winding and the stator windings, a small amount of alternating current (AC) is produced. The AC current is produced in the stator windings from the small magnetic field. The AC current is changed to direct current (DC) when the AC current passes through the diodes of the rectifier bridge. The current is used for the following applications:
Charging the battery
Supplying the low amperage circuit
Strengthening the magnetic fieldThe first two applications use the majority of the current. As the DC current increases through the field windings, the strength of the magnetic field is increased. As the magnetic field becomes stronger, more AC current is produced in the stator windings. The increased speed of the rotor assembly also increases the current and voltage output of the alternator. The voltage regulator is a solid-state electronic switch. The voltage regulator senses the voltage in the system. The voltage regulator switches ON and OFF many times per second in order to control the field current for the alternator. The alternator uses the field current in order to generate the required voltage output.
Never operate the alternator without the battery in the circuit. Making or breaking an alternator connection with heavy load on the circuit can cause damage to the regulator.
Illustration 1 g00425518
Typical alternator components (1) Regulator (2) Roller bearing (3) Stator winding (4) Ball bearing (5) Rectifier bridge (6) Field winding (7) Rotor assembly (8) FanStarting System Components
Starting Solenoid
Illustration 2 g00317613
Typical starting solenoidThe starting solenoid is an electromagnetic switch that performs the following basic operations:
The starting solenoid closes the high current starting motor circuit with a low current start switch circuit.
The starting solenoid engages the starter motor pinion with the ring gear.The solenoid has windings (one or two sets) around a hollow cylinder. A spring loaded plunger (core) is inside of the cylinder. The plunger can move forward and backward. When the start switch is closed and electricity is sent through the windings, a magnetic field is made. The magnetic field pulls the plunger forward in the cylinder. This moves the shift lever in order to engage the pinion drive gear with the ring gear. The front end of the plunger then makes contact across the battery and motor terminals of the solenoid. Next, the starting motor begins to turn the flywheel of the engine. When the start switch is opened, current no longer flows through the windings. The spring now pushes the plunger back to the original position. At the same time, the spring moves the pinion gear away from the flywheel. When two sets of solenoid windings are used, the windings are called the hold-in winding and the pull-in winding. Both sets of windings have the same number of turns around the cylinder, but the pull-in winding uses a wire with a larger diameter. The wire with a larger diameter produces a greater magnetic field. When the start switch is closed, part of the current flows from the battery through the hold-in windings. The rest of the current flows through the pull-in windings to the motor terminal. The current then flows through the motor to ground. The solenoid is fully activated when the connection across the battery and the motor terminal is complete. When the solenoid is fully activated, the current is shut off through the pull-in windings. At this point, only the smaller hold-in windings are in operation. The hold-in windings operate for the duration of time that is required in order to start the engine. The solenoid will now draw less current from the battery, and the heat that is generated by t