GM/Detroit 6.5L – GENERATOR BENCH TEST

This test requires both a fully charged battery and a generator test stand to operate the generator.
1. Make connect i ons as shown in figure 4, except leave the carbon pile turned off. The ground polari­ty of the generator and battery must be the same. The battery must be fully charged. Use a 30 to 500 ohm resistor between the battery and the “L” termi­nal.

2. Slowly increase the generator speed and observe the voltage.
3. I f the voltage is uncontrolled and increases above 16 volts, the rotor field is shorted, the regulator is not working properly, or both. A shorted rotor field coil can cause repeat regulator failure.

4. I f the voltage is below 16 volts, increase speed and turn on and adjust the carbon pile to obtain maxi­mum amperage output. Maintain the voltage above 13 volts.
5. If the output is within 15 amperes of the rated out­ put, the generator is good.
6. if the output is not within 15 amperes of the rated output, replace the generator.