The car generator is used to charge the battery, as well as to power the electrical components in the car: side lights, on-board computer, air conditioner and others. The generator provides the operation of many components of a modern car, in this regard, increased safety requirements are applied to it and is carefully checked.
Instructions
Step 1
Before carrying out checks, remember that it is strictly forbidden to disconnect the generator from the battery while the engine is running. This will cause a power surge and could damage the generator rectifier unit.
Step 2
Check the generator on the bench. This will allow you to find out whether its parameters correspond to the nominal characteristics. Make sure that the brushes under test are well ground to the slip rings. They, in turn, must be clean.
Step 3
Turn on the electric motor from the stand, set the output voltage to 14 Volts using a rheostat. Bring the rotor speed to 5000 rpm. After 2 minutes of testing, measure the current. If the generator is in good working order, then this figure will be at least 44 A. If the current value is less, then check the windings and valves to determine the location of the malfunction. To do this, measure the current on the heated generator. Let it run for about 15 minutes and then measure the current, which should be at least 42 A.
Step 4
Check the generator with an oscilloscope. Set the rotor rotation at a frequency of 1500-2000 revolutions. Connect the field winding to the storage battery, and disconnect the power from the terminal "30". Now pay attention to the screen of the device and check the generator's serviceability by the voltage waveform. If everything is in order, then the curve will have a sawtooth shape with uniform teeth. If there is a break in the stator winding or valves, then the teeth become uneven, and deep depressions appear.
Step 5
Measure the resistance between plug "67" and generator ground. This will allow you to determine the condition of the field winding. In good condition, the resistance should be in the range from 4, 2 to 4, 7 ohms. The size of the measurement depends on the temperature, therefore, measurements must be taken at 20 ° C.
