Bench Testing

Fig. 2 CS Alternator Bench Check:

1. Make connections as shown in Fig. 2, however leave the carbon pile disconnected. The ground polarity of the alternator and battery must be the same. The battery must be fully charged. Use a 30-500 ohm resistor between battery and L terminal.
2. Slowly increase alternator speed and observe voltage.
3. If voltage is uncontrolled and increases above 16 volts, the rotor field is shorted, the regulator is defective or both. A shorted rotor field can cause the regulator to become defective. Battery must be fully charged when making this test.
4. If voltage is below 16 volts, increase speed and adjust carbon pile obtain maximum amperage output. Maintain voltage above 13 volts.
5. If output is within 15 amps of rated output, alternator is satisfactory.
6. If output is not within 15 amps of rated output, alternator is defective and requires repair.