BOLT 8T9391 - Caterpillar

Illustration 1 g00874825
Wiring Diagram of the Self-Excited Generator (CR1-C6) Diodes (CR7) Varistor (L1) Exciter field (stator) (L2) Exciter armature (rotor) (L3) Main field (rotor) (L4) Main armature (stator) (RFA) Rotating field assembly (CT1) Optional Voltage Droop Transformer (T0, T1, T2, T3, T7, T8, T9) Generator terminalsSelf-excited generators may lose the residual magnetism that normally exists in the exciter field (L1) and the main field (L3) . Residual magnetism is necessary to start the generation process. The magnetism can be restored by flashing exciter field (L1) with direct current. A 6 VDC battery can be used to supply the direct current.
Do not flash permanent magnet pilot excited (PMPE) generators. Damage to the generator set can occur.
There are two methods of flashing the field:
Static Flashing (stopped engine)
Dynamic Flashing (running engine)Static Flashing (Stopped Engine)
Table 1
Tools Needed    
Tool    Quantity    
6 VDC Battery     1    
Stop the engine.
At the voltage regulator, disconnect wire F1 GEN from terminal F1 and disconnect wire F2 GEN from terminalF2.
Connect the positive cable of the 6 volt source to wire F1 GEN.
Momentarily put the negative cable of the 6 volt source on wire F2 GEN (two or three times). Note: Do not hold the negative cable to wire F2 GEN for more than one or two seconds.
Connect all wires that were previously disconnected.Dynamic Flashing (Running Engine)
Illustration 2 g00614470
Dynamic Flashing Circuit (1) Battery (≤ 6 VDC) (2) Diode (3) Red test lead "+" (4) Black test lead "-"
Table 2
Tools Needed    
Part Number     Tool     Quantity    
6V-7070     Digital Multimeter     1    
9P-5153     Diode
(MR-504)     1    
    Dynamic Flashing Circuit     1    
Construct the dynamic flashing circuit that is shown in Illustration 2.
Stop the engine.
Connect a multimeter (set on ACV) to terminals 20 and 22 at the voltage regulator.
Start the engine and run the engine at low idle.
Do not hold the flashing circuit's test leads on the terminals longer than necessary. This can cause the voltage to become too high. Excessive voltage can cause damage to the generator and can cause damage to the flashing circuit.
Hold the red lead of the dynamic flashing circuit to terminal F1.
Monitor the voltmeter. Touch the black lead to terminal F2 of the dynamic flashing circuit.
When the voltmeter shows an increase in voltage, remove the test leads from terminal F1 and terminal F2. If the generator voltage does not increase within 5 to 10 seconds, remove the test leads from terminals F1 and F2.