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TESTING THE TWO BRUSH GENERATOR CIRCUITS. First you should carefully inspect and trace all the wires in the charging system to determine if they are intact and going from and to their prospective places.
With an Ohm meter you should determine the continuity of each individual wire by disconnecting each wire individually one at a time at both ends and testing for no open breaks in that particular wire. Then go on to test the remaining wires. Most notably the Gen wire, the field wire and the battery wires. Be sure that the wire that comes up from the starter solenoid from the hot battery cable goes first through the ammeter and then to the junction block and on to the voltage regulator Battery terminal. If the wires are not connected as they are supposed to be to the right terminals or are broken there can be no movement of current to and from the battery and the generator/regulator circuits. Generators normally have two terminals. F or field is the ground or "regulated ground" terminal, and A or armature is the Hot or "regulated charging" terminal.
1. measure battery voltage, engine off.
2. start tractor and measure battery voltage, should be higher
3. if you don’t see a big increase in voltage then determine if problem is regulator or generator---to do this--
4. take both wires off the generator.
5. ground the F terminal to the tractor frame.
6.start tractor and measure the voltage at A terminal. if it is 20-30 volts the generator is good. if you have 5 volts, the generator is bad.
7. if generator output is good, run the A terminal wire to the amp meter, then to the battery lug. start tractor and see the voltage is 1 volt above battery and ampmeter show good charge. (just run 1-2 minutes.)
8. this proves regulator is bad if generator is charging without the regulator Troubleshooting The 2 brush Generator
The 2 brush generator and the voltage regualtor are troubleshot as a system.
Low or no generator output
Short the Armature terminal to the Bat terminal of the voltage regulator. (Do not touch the field terminal )Does output now come up to normal? If so, the VR is probably defective. If not, connect a jumper on the generator field terminal to ground. Does the generator now produce normal output? If yes, the VR is probably defective. If not go on to the next test.
Generator Motor Test.
Do not run engine for this test. Disconnect the wires from the generator. Disconnect the fan belt. Apply a jumper wire from the field terminal of the generator to ground. Apply a jumper wire from the battery negative to the armature terminal of the generator. Does the generator turn? If not the generator is probably defective. The generator should rotate in the direction of rotation same as the engine.
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