If the AC compressor is the heart of the AC system, the alternator serves as the heart of the vehicle's electrical system. Since the electrical parts of the automobiles operate via a battery or batteries, there must be something to keep feeding the battery or else, it will surely lose its voltage and fail to function. And the job of feeding the batteries is done by the vehicle's alternator. It is a belt-driven component that's used to transform the mechanical energy into alternating current.
Alternators are great replacements for generators on cars. With alternators, the output current can be generated at lower rpm, the voltage can be controlled precisely, less maintenance is required and they need lesser production budget. Automotive alternators are rated in terms of the amperage that they generate.
Just like the alternators for other vehicle makes, your BMW alternator is made up of a rotor, a stator, a rectifier assembly, a pulley and a set of brushes which is used to maintain electrical contact with the rotor. All these alternator components except for the pulley are confined in aluminum housing. Alternators in modern vehicles use compact, electronic voltage regulators that may be contained inside the alternator. In some cases, the work of the voltage regulator may be done by the power train control module of the vehicle.
The basic function of your BMW alternator is to produce direct current for recharging the battery and for motorizing the vehicle's electrical loads. With that vital task, BMW alternators need to be maintained and taken cared of. There are several steps which you can apply to keep your BMW alternator in tiptop shape and condition. Check the BMW alternator's drive belt tension at every oil change. A belt that's loose can lessen the output of the alternator and run down the car's battery as well. Before you travel every spring, it is always advisable to have your BMW alternator tested as part of a complete starting, charging and battery test.
Closer Look at BMW Alternator
When the engine of your BMW is running, the battery does not bear the bottom-line responsibility for the electricity that needs to be provided to the radio, the lights, and other electronics. That responsibility falls to the BMW alternator. In addition to powering the electronics, the BMW alternator is also responsible for recharging the battery, so that the vehicle may start the next time it is needed to. The unit is attached through a pulley and belt to the crankshaft pulley of the engine. As the engine runs, this belt turns the BMW alternator. The interior housing of this part is lined with a set of strong permanent magnets. In the center of the BMW alternator is a core made of iron, which is then wrapped in copper wires. When the core is turned by the pulley, the copper wires pass through the field of the magnets, and the magnets induce electrons within the copper wires to move. The result is electricity, and this electricity is transferred out of the BMW alternator by small spring arms, called brushes, that ride on the spinning inner core. The electricity produced by the BMW alternator is actually alternating current, which is then converted to the direct current that the vehicle needs with an internal voltage rectifier. When the BMW alternator in your vehicle fails, it is usually due to worn brushes within the unit, or a bad internal rectifier. When you need replacement, you will find the correct version for most vehicles in our large online catalog, at a great price. To order the BMW alternator for you vehicle, visit our secure web site, or place your order by phone, toll-free, at any time of the day or night.
3 Factors to Determine the Right BMW Alternator for You
As the main electrical supplier of your vehicle, a BMW alternator must be selected correctly to ensure great driving performance. Below are the three main factors you need to keep in mind so you will have the correct and exact fit.
Know the main parts
It is always good to have a basic knowledge about the main parts of a component. Typically, a BMW alternator has four main parts that include the rotor, stator, rectifier, and regulator.
- Rotor:This part consists of the shaft, iron core, winding, pole, and slips rings. It functions as a producer of amperage when the electrical windings rotate.
- Stator: Consists of the windings and steel stampings, the stator produces amperage on a stationary set of windings.
- Rectifier:This part comprises of diodes fitted in an insulator. It mainly converts AC voltage into direct current voltage as it travels to the battery.
- Regulator: This part comprises of different terminals, plus a heat sink. It controls the production of voltage, regulates the current flow, and may be installed either inside or outside the assembly. New vehicle models now mostly have alternators with internal regulators.
Besides the above main parts, there are other elements in an alternator that serve important functions in the operation. There is the pulley that drives the rotor off the engine's movement. A fan that is strategically positioned behind the pulley works by dispersing the heat and cooling the diodes, plus brushes to help the transference of electric current between the battery and alternator. Other important elements are the housing, which is usually made of cast aluminum so it weighs very light and dispels heat easily, plus the front and rear bearings that secure the housing in place.
Consider the total electrical load
You need to figure out the total electric load of you BMW to help you select the right alternator. One of the most accurate ways to know the load is by using an ammeter. When the engine is off and the battery charged, you can connect the ammeter and alternatively switch each electric component on and off. As you add up the readings, you can determine the amount of electrical load. Keep in mind that your BMW alternator output should be fifty percent higher than the amount. In case you do not have an ammeter, get an estimated load by inspecting the accessory fuses. Although the amp ratings are greater than the highest draw of each component, the total of all the fuse ratings will give you an overall idea of your electrical load.
Choose between brand new and refurbished
A cheaper alternative to a brand new alternator is a refurbished one. A refurbished alternator is an alternator that has been completely taken apart to thoroughly clean and check each component. Broken and defective parts are then replaced with brand new ones. In order to get the right refurbished alternator for your BMW, make sure to have it tested for power and select the one that has a longer warranty. Some high-quality refurbished alternators have a warranty ranging from one to three years.