cub 147 electrical

[bob f]

Bought a 147. I noticed when I start it the voltage gauge goes to the charge side, when running the gauge goes to the discharge side. Investigated and it looks like the positive from the battery goes to frame ground and the negative goes to the starter cellinoid. Everything works and keeps battery charged. My question is can I reverse the battery leads without doing anything else? Or will the starter turn backwards, or do I need to polarize the starter?

[ironman]

Originally Posted by bob f

Bought a 147. I noticed when I start it the voltage gauge goes to the charge side, when running the gauge goes to the discharge side. Investigated and it looks like the positive from the battery goes to frame ground and the negative goes to the starter cellinoid. Everything works and keeps battery charged. My question is can I reverse the battery leads without doing anything else? Or will the starter turn backwards, or do I need to polarize the starter?

Is this another crystal ball test question?
How about some details!
Like is the battery always dead or does it start and run fine except for the meter reading backwards?

[Billy-O]

This is second post within the past few months of mentioning of positive ground... can't remember the details of the previous thread ..... anyway.....

What aids did you use when you LOOKED?? Did you use a test meter that can determine polarity? It is easy to get lost when following wires snaking thru tractor by eye. Are you certain?

Easiest thing to remedy a backwards charge indicator at this point is swap wires on charge indicator if everything else work ok.

[bob f]

It starts and runs fine, battery not dead. I will take another look at connections.

[crazycubtrio]

I have seen the wires flopped on the ammeter cause the gauge to work backwards but as far as the battery cables being opposite….. I can’t imagine it starting and charging right

[LarryW]

If you reverse polarity everything will be backwards if it even work. Dont do that. I agree with crazycubtrio. Flip the ammeter gauge wires. Or leave it alone knowing its backwards.

[bob f]

After much research SG don't care if it is positive or negative ground. All the other components will work the same because no electronics involved. I reversed the battery connections and the leads to the electric lift and everything works. It is now negative ground, charging right, and lift is right. The SG will turn only one direction no matter what polarity ground it sees. The only way to reverse the SG is to redo the brushes inside.

[LarryW]

Interestingly strange. Any DC motor swapping wires around make them spin backwards and 3 phase AC swapping any 2 of the 3 wires does the same. I would guess the SG and lift would both spin backwards. But if its working thats cool. Something I dont understand going on I guess. lol Glad you got it going good though!

[Graflex45]

Originally Posted by LarryW

Interestingly strange. Any DC motor swapping wires around make them spin backwards and 3 phase AC swapping any 2 of the 3 wires does the same. I would guess the SG and lift would both spin backwards. But if its working thats cool. Something I dont understand going on I guess. lol Glad you got it going good though!

Permenent magnet DC motors change direction when you switch polarity. With a series field winding of the starter generator I don't think it would matter the polarity because the motor is relying on opposite fields attracting. Switching the magnetic polarity doesn't really matter, the electromagnets are still going to pull the same.
Having read all the Delco Remy booklets and datasheets I could get my hands on to fix my own SG problem I will say you should make sure you have a regulator that will deal with positive ground. It says the original ones of the era had the contacts made of different metals to minimize putting and cratering which wore them out. Later replacements including an American Bosch regulator I found (new in box and unrusted!) specify they have harder metal contacts and work fine on either polarity.