The alternator's charging output increases in proportion to the electrical load on the charging system and engine speed. Output is low at idle and increases with RPM. Maximum output is typically achieved at speeds above 2, RPM. Charging output of the alternator is controlled by a voltage regulator which may be mounted inside or on the back of the alternator internally regulated , or somewhere else under the hood externally regulated.
On most newer vehicles, the powertrain control module PCM regulates charging output. On older vehicles, the voltage regulator was electro-mechanical and used magnetic contacts to control the charging output of the alternator. Since the s, most voltage regulators are solid-state electronic and use transistors to control charging output.
At idle, most charging systems will produce Most alternators that are charging properly should produce a voltage of about Always refer to the vehicle manufacturer's specifications. Many Asian vehicles, for example, have higher charging voltages of around 15 volts. When the engine is first started, the charging voltage should rise quickly to about two volts above base battery voltage, then taper off, leveling out at the specified voltage.
The exact charging voltage will vary according to the battery's state of charge, the load on the vehicle's electrical system, and temperature. The lower the temperature the higher the charging voltage, and the higher the temperature the lower the charging voltage.
The "normal" charging voltage on a typical application might be But at 20 degrees F. On a hot engine on a hot day, the normal charging voltage might drop to In addition to checking the alternator's voltage output, you also need to check its current or amperage output.
Amperage is how much current the alternator generates at a specified voltage and speed. Not long ago, an 80 amp alternator was considered a high output unit. Most late model alternators produce to amps or more. Current output increases with engine speed, from around 20 to 50 amps at idle up to the unit's maximum output at 2, RPM or higher refer to a service manual for the exact charging output specifications for your vehicle.
It can also be measured on an alternator bench tester in a auto parts store. Alternator power ratings can also be given in Watts which is volts times amps. Many alternators in foreign vehicles are rated in watts rather than amps. The important point here is to make sure a replacement alternator has the same power rating in amps or watts as the original so the charging system can maintain the same power output as before, should the alternator need to be replaced.
In fact, on some applications upgrading to a higher output replacement alternator may be recommended if the vehicle has a history of alternator failures, or the vehicle has a megawatt aftermarket sound system, emergency or off-road lighting, or other power-hungry electrical accessories. If the alternator is working hard under a heavy load at low RPM especially during hot weather , there may not be enough cooling to prevent the unit from overheating.
This tends to be more of a problem on vehicles where the location of the alternator restricts airflow and cooling. The alternator may be forced to work harder than normal if the battery cables, ground straps or other electrical connections in the charging circuit are dirty or loose.
A stretched or slipping alternator drive belt may cause the alternator to not produce a full charge. The belt should be inspected to assure it is properly tensioned and not damaged.
A drive belt should be soft and pliable. He was great with explanation of the issue, as well as making the repairs to my car efficiently. I highly recommend him as a mobile mechanic to anyone I know! Robert 20 years of experience. Request Robert. Mercedes-Benz C V Was on time and completed the job to my satisfaction. Will use again when any of my cars or trucks needs work done to them. Thank you. Robert is a great mechanic, and I will definitely be looking to use him for further work.
I used to troubleshoot and work on cars, but I lack the expertise to tackle modern electrical systems. Robert efficiently diagnosed the problem, and fixed the car within the estimated timeframe. Need Help With Your Car? Related articles. Test your car in different gears and check the fluids. Read more. How to Troubleshoot a Parking Brake or Emergency Brake That Won't Engage Emergency brakes won't engage if the parking brake lever or pedal is out of adjustment or there are worn brake shoes or brake pads.
How to Troubleshoot a Small Engine Problem Small car engines need attention if the car won't start, there's a loss of power, the car stalls or overheats, or if the car backfires. There are many dash warning lights on your instrument cluster or dashboard. The one that stands out the most is the one that gets the most attention in most cases. These different warning lights come in different colors like red, Steering wheel hard to turn after alternator replacement Have the system scanned to see what is causing the light to turn on first.
The low voltage conditions might have caused the problem and would need diagnosis of the code to fix the issue. The first and easiest step is to trace the wiring circuit involved with the starting system, and visually inspect it for any physical damage Browse other content. Schedule your Alternator Repair today!
Alternator Repair. When an alternator begins to fail, it provides inconsistent voltage to your electronic accessories.
Generally, that takes the form of under- or over-performing equipment, such as headlights that are either too dim or extremely bright. You may also experience flickering lights or lights that erratically go from bright to dim and vice-versa.
Other times, however, a dead battery could be a sign that your alternator is malfunctioning. One way to test whether the issue is battery- or alternator-related is to jumpstart the car. If you jumpstart your car and it stays running, your battery may need replacing soon. As previously mentioned, trouble starting your engine might mean that your alternator is failing to charge the battery. This means that when you turn the key in the ignition, all you'll hear is a clicking sound instead of the purr of your engine.
Cars make a ton of odd sounds — some are harmless while others can indicate serious mechanical problems. If you ever hear growling or whining noises coming from under the hood, you could have alternator problems, which should be checked out by a professional ASAP.
You may also hear this sound if the bearings that spin the rotor shaft are going bad.
0コメント