Alternator Wiring Diagram
This topic deals with the trouble shooting and repair of the alternator in our cars. The Alternator it self in this example is just 40 Amp/ 12 volts. The rectifier and the regulator is internal. But first we have to know some basic things about the alternator. Why do we need it in our cars ? Basically it is just the charger of our battery, so that the power lost by the battery will be replenish again for some other used like for starting the engine time and time again and some other load like, glow plugs, lights, horn, and many more. If we open an alternator we will noticed that it is just composed of three things :
1. Generator – This generate the alternating current
2. Rectifier – Converts the a/c power to d/c
3. Regulator – This regulates the output power so that we could not over charge the battery and the parameters for voltage and current is in range for consumption to avoid damage for the device and the loads, since the acceleration of the engine is always changing. This is accomplished by varying the supply of the field coil by the use of slip rings in the shafting.
How to test the Alternator:
1. Connect the wiring in the figure. In this sample, I got a 5 w/ 12 volts bulb. If you followed the wiring correctly the light should be on like in the picture.
2. Measure the voltage in the battery terminal. In this case it is 12.5 volts
3. Connect a drill machine with socket wrench and run the drill. You will noticed that the light bulb will slowly turn off as we increase the speed of the rotation of the drill machine. You should have a volt meter or a tester to measure the terminal voltage. When the bulb completely turn off measure again the voltage, It should register a reading of 14 volts to 14.5 volts . Depending on the alternator and the battery charged level. If that is the case we could say that the alternator is charging the battery. If we have a clamp meter ( d/c clamp meter ) we could find out how much current does it is charging the battery.
4. Some problems that we may encounter in our alternator is the carbon brush if it is worn out already. So you might want to check it first before deciding to replace anything.
5. Here is another sample of a Regulator/Rectifier assembly.
6. If your problem is how to remove the pulley and the cooling fan so you to transfer it to the new unit that you bought. You have to dismantle the alternator, and put the body of the rotor on a vice and remove the nut that holds the pulley in placed. Then you can now remove the pulley and the cooling fan.
Here is a sample of a stator of the alternator