C 2500 Truck 2WD V8-5.7L VIN R (1997)
5. If the voltage is below 16 volts, increase speed and adjust the carbon pile to obtain maximum amperage output. Maintain the voltage above 13
volts.
6. If the output is within 15 amperes of the rated output, the generator is good.
7. If the output is not within 15 amperes of the rated output, replace the generator.
Grounded Winding Test - CS-144 Generator
Connect a test lamp or ohmmeter from one slip ring to the shaft. If the lamp lights, or if the reading is low, the rotor winding is grounded. Replace the
rotor.
Open Winding Test - CS-144 Generator
To test for opens, connect the test lamp or ohmmeter to each slip ring. If the lamp fails to light, or if the ohmmeter reading is high (infinite), the winding
is open. Replace the rotor.
Rectifier Bridge Test - CS-144 Generator
Rectifier Bridge Test
To test the rectifier bridge, connect an ohmmeter to the grounded heat sink and one of the three terminals, while pressing down firmly on the flat metal
clip. Observe the ohmmeter reading and reverse the lead connectors to the grounded heat sink and the same metal clip. It both readings are the same,
replace the rectifier bridge. A good rectifier bridge will give one high and one low reading. Repeat this procedure between the grounded heat sink and
the other two terminals, and between the insulated heat sink and each of the three terminals. This makes a total of six tests, with two readings taken for
each test.
Some digital ohmmeters cannot be used to test diodes in the rectifier bridge. Consult the ohmmeter manufacturer to determine your ohmmeter's
capabilities.
Rotor Field Winding Tests - CS-144 Generator
Regulator Connections
The rotor may be tested electrically with a self-powered test lamp or an ohmmeter.
Short Circuit or Resistance Test - CS-144 Generator
Test the winding for short circuits or excessive resistance by connecting a battery and ammeter in series with the edge of the two slip rings. Note the
ammeter reading and refer to "Generator Specifications,". An ammeter reading above the specified value indicates shorted windings.
An alternate method is to check the resistance of the field by connecting an ohmmeter to the two slip rings. If the resistance reading is above the
specified value, the winding has excessive resistance; if it is below the specified value, the winding is shorted. The specified resistance value can be
determined by dividing the voltage by the current.
Remember that the winding resistance and ammeter readings will vary slightly with winding temperature. If the rotor is not defective, but the generator
fails to supply rated output, the problem is in the rectifier bridge, stator, or regulator.
