'52 8N Generator problem

[Bill(NC)]

My neighbor's 6V Neg ground system. The wiring looks real good. It was not charging.

The generator was not putting out. We disconnected all wires to it, grounded the field to the generator ground terminal, and it still had no output.

We disconnected the belt, grounded the field and applied +6V from the battery, and the generator motored.

Then my neighbor took the generator to a shop. I don't know everything they did, but they said that the brushes could be bad and replaced them. They were supposed to have set it up for a negative ground system.

We put the generator back in the tractor, and got the same results (no output).

Question: We bumped the starter and could see that the engine was rotating clock wise looking from the front. When we made the generator motor, it was running counter clock wise. Is this what we should expect? we could not get it to rotate clock wise.

Do you have any suggestions? HELP!

 

[R Geiger]

the 6 volt 8N's were all positive ground.

 

[JMOR]

(quoted from post at 17:42:23 04/29/11) the 6 volt 8N's were all positive ground.

es, from the factory, but by simply swapping battery cables & re-polarizing the generator all will be well as NEG ground. So his tractor may very well be NEG ground.

 

[R Geiger]

Just wanted to point that from the factory they were postive ground. Does the voltage regulator handle neg ground OK? Just wondering.

 

[JMOR]

(quoted from post at 18:15:44 04/29/11) Just wanted to point that from the factory they were postive ground. Does the voltage regulator handle neg ground OK? Just wondering.

hese do, but there are/have been designs that do not tolerate reversal.

 

[R Geiger]

OK, thanks for the info. Maybe it never got re-polarized.

 

[JMOR]

(quoted from post at 17:40:00 04/29/11) My neighbor's 6V Neg ground system. The wiring looks real good. It was not charging.

The generator was not putting out. We disconnected all wires to it, grounded the field to the generator ground terminal, and it still had no output.

We disconnected the belt, grounded the field and applied +6V from the battery, and the generator motored.

Then my neighbor took the generator to a shop. I don't know everything they did, but they said that the brushes could be bad and replaced them. They were supposed to have set it up for a negative ground system.

We put the generator back in the tractor, and got the same results (no output).

Question: We bumped the starter and could see that the engine was rotating clock wise looking from the front. When we made the generator motor, it was running counter clock wise. Is this what we should expect? we could not get it to rotate clock wise.

Do you have any suggestions? HELP!

"Question: We bumped the starter and could see that the engine was rotating clock wise looking from the front. When we made the generator motor, it was running counter clock wise. Is this what we should expect? we could not get it to rotate clock wise. " No. I would guess that you have no field current & it is operating off of residual magnetism only. If that is true, reversing the voltage polarity applied for motoring it will reverse direction of rotation. If you do have field current then reversing applied polarity will not reverse direction of rotation. If determine you have no field current by outlined observation, take it back to your gen shop. Another indication of field current or no field current is; while motoring, remove the field terminal connection and look for a change in speed. If no speed change, then you didn't have field current.

 

[Dean]

You will need to polarize the generator.

If the VR is good and the wireing is correct the system should charge.

Dean

 

[teddy52food]

Anytime you motor a generator, it is polarized.

 

[Bill(NC)]

Thanks JMOR. I had tried changing the polarity, and there was no change. I guess that means there is field current. I will try removing the field current connection and look for a change in speed. If there is field current, then why do you think it is running backward?

 

[JMOR]

(quoted from post at 22:08:57 04/29/11) Thanks JMOR. I had tried changing the polarity, and there was no change. I guess that means there is field current. I will try removing the field current connection and look for a change in speed. If there is field current, then why do you think it is running backward?

retty much has to be something the gen shop did, because the way this gen works, is that field is powered by an armature brush & that is internal connections in the generator case. When you reverse the polarity of applied voltage, you then reverse BOTH the armature AND the field, so since BOTH are reversed it will run the same direction. The only way the ARM or the FIELD can be reversed independently of one another is by altering the internal wiring of the generator & the result is a reverse rotation. Back to gen shop! And don't let them charge you for their mistake.

 

[36 Coupe]

The shop cant set it up for a negative ground system.They can motor it connected as neg ground.Take the cover off the voltage regulator.Start the engine, close the cut out points with your finger.Look at the ammeter if its charging you have an open shunt coil in the cutout.Working on a generator disconnecting wires with out basic knowledge of how it works will get you in trouble.If you did that to a 3 brush generator the voltage would climb enough to open or cook the shunt coil in the cut out relay.

 

[36 Coupe]

How did the generator shop make a mistake?

 

[JMOR]

(quoted from post at 04:54:54 04/30/11) How did the generator shop make a mistake?

6, I can't say how they messed up since I wasn't there, but you are old enough to have a pretty good idea how mess-ups/mistakes are made. Some possibilities are carelessness, don't care, inattention, drunk/drugs, inability, lack of knowledge, applying some knowledge incorrectly, confusion, misunderstanding, etc.