TUBE AS 4392498 - Caterpillar

Troubleshooting Charts
Initial Operating Procedure After Repairs
The engine should not be operated at rated RPM immediately after the cause for the fault condition has been repaired. The following procedure may prevent additional failures if the actual cause of the fault condition was not detected.1. Remove build-up relay (K1) and disconnect wire (8) from regulator assembly (A1).2. Start the engine and operate it at low idle RPM. The residual magnetism in the field should produce approximately 2 to 10 volts (generator output). A shorted controlled rectifier (CR1) will allow the field to produce higher output voltage.3. Stop the engine and install build-up relay (K1).4. Start the engine and operate it at low idle RPM. The output voltage will vary (up and down) when the points in the build-up relay are properly operating. If the output voltage is 2 to 10 volts and steady, either the build-up relay points are open or the controlled rectifier is open. If the build-up relay points remain closed, generator voltage will be higher and steady.5. Stop the engine and reconnect the wire to terminal (8).6. Start the engine and operate it at low RPM. The output voltage should be approximately 66% of generator rated voltage. If the output voltage is either too high or is not steady, the reference circuit may be open or the regulator assembly may be defective.7. With the engine operating at low idle RPM and the generator producing a steady voltage (approximately 66% of rated voltage), slowly increase the RPM to rated RPM. Adjust the voltage level control to generator rated voltage. The generator is now ready to use.Flashing The Field
If the generator revolving field poles lose residual magnetism, the magnetism may be restored by "flashing" the revolving field windings with a direct current 24 volt source (battery).
DO NOT OPEN OR CLOSE THE EXCITER WITH THE ENGINE-GENERATOR OPERATING. When the generator is operating, the heat sinks and exciter parts are electrically charged. Components will be damaged if metal contact is made between the generator frame and the heat sinks or exciter parts.
Static Flashing
With the engine stopped, disconnect revolving field (L3) wires; C1 from terminal TB2-1 and C2 from terminal TB2-2. Connect the positive "+" lead of the 24 volt source to wire C1. Momentarily apply (two or three times) the negative "-" lead of the source to wire C2. Correct polarity must be maintained (C1 is positive "+" and C2 is negative "-"). If the polarity of the field is reversed, the field rectifier will be damaged.Dynamic Flashing
A more positive method of flashing the field can be effected by applying the DC source to the field while the engine is operating at low idle RPM.With the engine stopped, connect an accurate AC voltmeter to terminals TB2-3 and TB2-4. Connect the positive "+" lead of the 24 volt source to terminal TB2-1 and the negative "-" lead to terminal TB2-2. Start the engine and observe the voltmeter. When the voltmeter begins to indicate a voltage, carefully disconnect the DC source from terminals