How to check alternator with multimeter

Automobile alternator is used to supply all of the electrical devices of the vehicle after starting the engine. He must always be in good condition because of his work depends on correct charging of the battery. In addition, the generator allows you to connect to the onboard network additionally many different devices. It should regularly monitor its technical condition. To check the generator with a multimeter or on a special stand.

You will need

• - multimeter.

Instruction

1. Check the relay-regulator. It serves to maintain the optimum value of the voltage in an onboard network of the car. Relay-regulator does not allow him to rise to critical levels. Start the vehicle. Switch multimeter to "voltage measurement". Measure the power supply on-Board network. This can be done on the outputs of the generator or the battery terminal. It should be around 14-14,2 V. Press down on the accelerator. Recheck the reading. If the voltage has changed more than 0.5 V, it is a sign of improper operation of the relay controller.
2. Check the diode bridge. It consists of six diodes. Three of them are positive and three are negative. Switch multimeter in mode "sound". Now with the closure of the contacts of the tester until you hear a beep. Test in both forward and back. Ate in both cases, the audible squeak, then the diode is broken and should be replaced.
3. Check the stator of the generator. It is a metal cylinder, inside of which special way winding is stacked. To check disconnect the output of the stator from the diode bridge. Inspect the condition of the windings for mechanical damage and burning. Turn the multimeter to "measure resistance". Check the coil for breakdown. For this purpose one contact of the tester press to the body of the stator, and the second to one of the terminals of the winding. If the resistance is tend to infinity, then it is serviceable. Readings less than 50 Ohms warn about the imminent failure of the generator.
4. Check the generator rotor. It is a metal rod, which is wound with the excitation winding. At one end are the slip rings on which brushes slide. After extraction of the rotor, inspect the condition of the bearings and the rotor winding. Check the continuity of winding. Turn the multimeter to "measure resistance". Measure the value between the two slip rings. If the resistance is small, the winding is OK. More detailed testing carried out on special test walls specialized STO.