Charging system
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The charging system allows for a means to re-charge the battery and allow for electrical usage of components in the vehicle.
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Alternator principles
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In the alternator a magnetic field rotates and the conductors are stationary. Mechanical energy is converted to electrical energy by electromagnetic induction.
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Alternating current
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The value of the induced EMF depends on the strength of the magnetic field, the speed at which the magnet rotates and the number of turns of wire on the stationary coil.
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Alternator components
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The maximum current that can be delivered by the alternator is designed during manufacture and so the alternator does not require a current regulator.
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Rectification
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Automotive alternators use a 3 phase bridge rectifier that has 3 positive diodes and 3 negative diodes to rectify the AC current in the 3 phase stator windings to produce a DC output.
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Phase winding connections
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Two methods of connection can be used for the stator. Star or wye connection and delta connection.
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Rotor circuit
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When the ignition is first switched o current flows through the charge indication lamp, the rotor windings and voltage regulator to ground. Current flow through the rotor winding is controlled by the voltage regulator when the engine is running.
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Voltage regulation
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The regulator switches rapidly between the ‘on’ and ‘off’ conditions, to allow the alternator to maintain an output voltage of approximately 14 volts.
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System operating voltage
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The maximum current output of the alternator at system operating voltage is designed during manufacture.
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| High voltage charging systems |
To meet the increased demand from such high usage systems as electric drives, higher voltage batteries and packs with an appropriately high voltage charging system are necessary. |
