The charging circuit operates when the engine is running. The alternator in the charging circuit produces direct current for the electrical system.
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| Illustration 1 | g00295928 |
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Typical example of starting motor (1) Terminal for connection of the battery cable (2) Terminal for connection of the ignition switch | |
The starting motor turns the engine flywheel. The rpm must be high enough in order to initiate a sustained operation of the fuel ignition in the cylinders.
The starting motor has a solenoid. When the ignition switch is activated, voltage from the electrical system will cause the solenoid to move the pinion toward the flywheel ring gear of the engine. The electrical contacts in the solenoid close the circuit between the battery and the starting motor barely before the pinion engages the ring gear. This causes the starting motor to rotate. This type of activation is called a positive shift.
When the engine begins to run, the overrunning clutch of the pinion drive prevents damage to the armature. Damage to the armature is caused by excessive speeds. The clutch prevents damage by stopping the mechanical connection. However, the pinion will stay meshed with the ring gear until the ignition switch is released. A spring in the overrunning clutch returns the clutch to the rest position.
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| Illustration 2 | g00303424 |
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Alternator (1) Shaft for mounting the pulley | |
The alternator produces the following electrical output:
- Three-phase
- Full-wave
- Rectified
The alternator has brushes. The alternator is an electro-mechanical component. The alternator is driven by a belt from the fan drive pulley. The alternator charges the storage battery during the engine operation.
The alternator is cooled by an external fan which is mounted behind the pulley. The fan forces air through the holes in the front of the alternator. The air exits through the holes in the back of the alternator.
The alternator converts the mechanical energy and the magnetic energy into alternating current and voltage. This conversion is done by rotating a direct current electromagnetic field on the inside of a three-phase stator. The electromagnetic field is generated by electrical current flowing through a rotor. The stator generates alternating current and voltage.
The alternating current is changed to direct current by a three-phase, full-wave rectifier. Direct current flows to the output terminal of the alternator. The rectifier has three exciter diodes. The direct current is used for the charging process.
A solid state regulator is installed on the rear end of the alternator. Two brushes conduct current through two slip rings. The current then flows to the rotor field. A capacitor protects the rectifier from high voltages.
The alternator is connected to the battery through the ignition switch. Therefore, alternator excitation occurs when the switch is in the ON position.
Note: Fuses protect the electrical system against short circuits. The risk of a short circuit is highest when the electrical system is being connected.
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| Illustration 3 | g00746261 |
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Typical arrangement Refer to Table 1 for a description of each fuse. | |
| Fuses for the 3054 Marine Engine , the 3054B Marine Engine , and the 3056 Marine Engine | ||
| Location | 3054 and 3054B Marine Engine | 3056 Marine Engine |
| 1 | 40 amp fuse for the starting motor | 40 amp fuse for the starting motor |
| 2 | Empty | 25 amp fuse for the air inlet heater (if equipped) |
| 3 | 10 amp fuse for the control panel | 25 amp fuse for the stop button |
| 4 | 25 amp fuse for the negative battery cable | 10 amp fuse for the control panel |
| 5 | Starting motor connection | Starting motor connection |
The fuses are located above the starter motor on the right rear side of the engine on the 3056 Marine engine. The fuses for the 3054 Marine engine and the 3054B Marine engine are located on the left rear side of the engine above the starter.
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| Illustration 4 | g00746263 |
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Cutaway view of the typical location (6) Negative fuse (7) Belt guard | |
An additional fuse is located at the front of the engine behind the belt guard. The fuse protects the engine wiring from damage. Do not connect the positive battery terminal to the cylinder block. Damage to the electrical system can be the result.