The alternator is responsible for charging the car battery and powering all the car's onboard network consumers. If it fails or is unstable, the battery will either not be charged or start discharging too quickly. It is necessary to monitor the condition of this car part to prevent this from happening.
The one sure way of doing precisely that is to run tests. But, as things can get complicated with them, it’s best to get to them only when you know everything there is to know about alternators. And this article will cover everything there is.
An alternator is a device that converts mechanical energy into electrical energy. In the construction of vehicles, it performs the following functions:
You can verify the alternator’s condition with special equipment, but that can be challenging. But, to simplify things, there are a couple of common causes we can focus on.
This occurs due to natural wear and tear or may appear because of a poor alternator repair job or incorrectly assembling or disassembling the part’s housing.
Burnout can occur for several reasons. One possible cause is a sudden temperature drop caused by water getting on the alternator, driving through puddles, or washing the engine. It destroys the winding insulation varnish. Subsequently, water or other liquids on the alternator will act as a conductor for the electric current, resulting in a short circuit.
The alternator brushes are in constant contact with the slip rings, so they experience friction due to alternator shaft rotation. It is only a question of time before the brushes become worn. Depending on the alternator’s design, namely the type of voltage regulator, the brushes can be replaced separately from the expensive relay. Otherwise, the entire voltage regulator must be replaced.
Apart from natural deterioration, any alternator component failure can bring about issues, but it’s also possible any other car part is the cause. For example, a short circuit in the stator winding, diode bridge breakage, and short circuit in battery banks can easily cause alternator malfunction.
Diode bridge failure can be caused by faulty batteries, a short circuit in the alternator stator winding, heat generated by loose connections, etc.
No matter the scenario, the alternator is an essential part. If you suspect a malfunction, you should inspect the bridge and use technical documentation and the manufacturer’s instruction to guide you.
Before getting to the tests, a few warnings. Under no circumstances should you simulate a short circuit to determine faultiness, as it could put you or other people helping you at risk. Also, never try to check out the generator’s performance when it’s disassembled.
The easiest way to test an alternator is by using a multimeter. If that’s a tool you have on hand, just follow these instructions:
If you don't have a tester, you can do the test without any tools. It is a very simple method, and it can surely show whether the alternator works correctly or if there are malfunctions. It should be noted that this method is not recommended for vehicles with complex electronics as things may get dangerous!
Start the engine and turn on dipped beam headlights to run the test. As in the multimeter method, you must first remove the minus terminal from the battery. The alternator works fine if the headlights give a steady light and the engine beat does not go off. If the headlight brightness changes or you’re unsure how to interpret the results, it is better to contact a specialist for complete diagnostics.
The alternator is the main source of power for all car onboard networks. If it becomes faulty, you won’t be able to drive on the battery alone, and thus, you should try to understand what went wrong. To do that, use the test methods we described above. Just follow the instructions, and everything will work. However, if you’re not sure you’ll be able to conduct tests on your own, drive to the nearest auto shop and ask for help.
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© 2023 J.D.Power. All rights reserved.
© 2019 J.D.Power. All rights reserved.