MF 135 Generator test

[dagwood]

Hi there, i a have MF135 gas 1967 tractor w/generator. I Think the generator is bad, but i dont know. My question is how do you test one of these?

 

[MIKE R]

Welcome to the forum. A generator requires the battery to be hooked up to create a magnetic field which in turn creates power. Have you disconnected the battery recently. Generators need to be polarized after being disconnected. What is the charging rate on the ammeter? It should be about 10 amps.

 

[murphy1244]

:welcome:

 

[The kid]

Hi there, i a have MF135 gas 1967 tractor w/generator. I Think the generator is bad, but i dont know. My question is how do you test one of these?

All these test can be performed with the genny still mounted on the tractor.

Generators when disconnected from a battery can lose their polarization. Positive or negative ground reference.

To polarize a generator for a 12V negative ground:

1. Remove the fan belt from the vehicle or machine the generator starts. You may be able to peel it off by hand, if not, loosen the sway bar arm with a socket set.

2. Attach the jumper wire to the armature terminal on the generator. This terminal will be labeled with an "A."

3. Touch the other end of the jumper wire to the positive terminal on the battery. Only touch the battery for a second. If you touch the positive terminal for longer, you will damage the generator.


To Test a Generator


Remove belt from generator to allow gen pully to freewheel.

1. Disconnect the negative battery cable with a wrench. Clip the jumper cables to the battery terminals: red to positive, black to negative.

2. Remove the hot (positive) wires from the generator's field and armature terminals with a wrench and screwdriver.

3. Clip the black (ground) jumper cable to the terminal on the generator marked "field." Clip the red (positive) jumper cable to the terminal on the generator marked "armature." If the armature does not spin, it is faulty.

4. Insert the red positive lead from the voltage meter under the red jumper cable clamp.

5. Remove the black jumper cable from the generator's field terminal and immediately clip it to the black negative lead from the voltage meter. This should cause the generator to speed up and the reading on the voltage meter to steadily rise, topping out between 12 to 13 volts. If either fails to happen, the armature is starting to fail, and you should replace or rebuild the generator.

Credit to: ehow.com