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Charging Sytems: Generator / Alternator / Dynamo

There is a charging system in each car, and it is there to recharge the battery and to supply the whole car with electric current and power. In most modern cars an Alternator is fitted to provide electrical power, but in old cars you can still find that a Dynamo with a regulator or control box does the job that an Alternator does with an built in regulator or external regulator, and in some cases on even newer cars the Alternator is controlled by the Electronic Control Unit or ECU. The ECU can decide to increase or reduce the output of the Alternator, to help efficiency, acceleration and even emission control.

If your Alternator is faulty, various symptoms can occur from simply having a flat battery, warning lights appearing, noises from the bearings or pulley and even overcharging. Nowadays it is not always the case that the battery warning light on the dash meaning a straightforward Alternator replacement is needed, often on modern cars the battery warning light is computer controlled and the Alternator receives a digital or computer signal from the main electronic control unit. It is important to diagnose a charging fault carefully so that you only buy the part you need, avoiding an expensive repair is where we at startermotoralternator.com can help. All our parts are high quality and competitively priced.

Remember to disconnect the battery when working on you Alternator and ensure that you mark clearly where wires and connector plugs are removed so that you refit them in the correct place. You should always charge your battery before fitting a replacement Alternator. If you are unsure always seek the advice of a specialist. A specialist or mechanic or auto electrician, will also help you identify the cause of failure as well as identifying the part that needs replacing. In a lot of cases another problem on your vehicle may have caused the failure of the Alternator, and these can include pulley damage or failure due to a faulty tensioner, burn out due to poor battery, excessive drive belt dust and corroded or poor connections. All our products come with technical notes to help where there are known common faults to help you fix your Alternator issues first time.

Below are some of the most common Alternator failures

  • slip rings are soiled, burned or oiled
  • drive belt slipping
  • excitation circuit is broken or incomplete
  • bearings are worn-out or damaged
  • pulley of the alternator is loosened or pulley clutch has failed
  • internal windings burn out
  • bracket seat is worn-out, broken or cracked
  • periodical brushes jamming, or stuck due to ingress or overheat

Signs of alternator failures

  • battery is discharged or boils away;
  • excessive noise when the unit starts working;
  • warning lights or message indicating low charge battery
  • dim headlights;
  • squealing belt noise
  • alternator charging when engine revs are increased

Diagnostics and fault finding The diagnostics of the unit should be carried out with the help of the ammeter and the voltmeter. It is possible to do it yourself or with help of a specialist. A poor earth or main feed from the battery must also be considered, it is important to check the old part you remove for the warning signs of failure, and if there is another fault on your vehicle it will need rectification otherwise it will cause your newly fitted replacement to fail prematurely.

Serviceable Life of an Alternator Usually the alternator service life is about 100,000 miles. However this depends on the actual type of use and the application, as some Alternators do not last as long as others due to their design or high demand. Normally the drive belt is replaced at the same time as a replacement Alternator is fitted.

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