4841 Alternators & Batteries

Alternators

Rotor windings

This week in class we started new subject alternators. First we had to disassemble it and carry out a test on rotor winding to ground test. To carry out these test all u need it a Multimeter, we had to set the Multimeter on 2k and place the positive lead on the rotor shaft and the negative lead on the slip rings and the reading should be infinity, if we get a reading that means that the rotor windings is shorted to the ground and we need to replace. After this this test we carried a test on internal resistance (slip rings) and according to the specs we need to within 2-6 ohms.

Stator windings

The next test we carried out was on the stator windings to carry out this test we had to place the negative lead on the common point (the one with most wires) and the positive lead on the other winding terminals, to meet the specs we had to get a reading between 0.0-.2 ohms the readings we got was 0.00 so we were within the specs. After the test we had to carry out a ground test for this we did set the Multimeter on 2k place the positive lead on the common terminal and the negative on an alternator body, to meet the specs we had to get a reading infinity if there was a circuit the stator has grounded and needed to replace. The readings we got was infinity and we were within the specs.

Rectifier positive & negative diodes.

The rectifier is the part that coverts the ac current to dc current, for the rectifier to meet the specs, out of four terminals the three terminals should show high resistance and one terminal to show infinity.

Voltage regulator

To test the voltage regulator we had to use a Transpo regulator tester, by using the information chart we had to set the tester on 12 volts and field current to 0.5 amps and had to connect the leads according to the diagram of the regulator. To meet the specs we had to get a reading of 14.6 volts.

It is used in alternator to maintain a constant level of voltage to the battery when required.                                                                                                            

The next day in class we had to do an assessment on car similar to what we did in the class.

Batteries

The last day of this week we got introduced to batteries the first thing we had to do was a visual check on the company, model no and cc rating. Then another visual check we had to do was on loose connections, corrosion, cut or any damaged wires and leaking on the batteries. After that we had to check the electrolyte levels and we did an open circuit voltage test and then find out the state of charge. Then we carried out a electrolyte specific gravity test and refill the battery if the water is low, record the readings on each cell and the colour of water in it (murky or clear). We finished of the day by carrying a load test on the battery using a load tester.