Anonymous-0
Well-known Member
I just had the generator rebuilt on my Farmall 400 gas. Its a 12 volt system negative ground. I got a new regulator hooked everything up. The amp gauge is reading -15 amps. What did i do wrong? Thanks for any help.
- Thread starter Anonymous-0
- Start date
Need more information to be better able to help you. Is the engine running when you get the -15 amps reading?
Are you sure it's negative ground? If it really is, maybe you have the wrong regulator?
Also new regulators aren't always good. New ones have been known to be bad.
Are you sure it's negative ground? If it really is, maybe you have the wrong regulator?
Also new regulators aren't always good. New ones have been known to be bad.
When the Genny was rebuilt perhaps the shop had it Polarized at opposite from your tractors ground????????? If ran that way too long you can fry a Voltage Regulator!!!!!!!!!! Also some VR's are suitable for Pos Ground others for Neg ground so you may wanna check that.
First thing Id do is try to re Polarize the genny n see what happens??????
Sure the ammeter is at the correct polarity and the battery was installd at right polarity matching the gennys polarity and the ammeters??? If the tractors not running and you switch on lights or ignition ammeter should swing to - discharge DOES YOURS??? If not either battery polarity has been reversed or ammeter needs its leads swapped. AGAIN RE POLARIZE THE GENNY N SEE WHAT HAPPENS and see if the battery is right and ammeter. The genny shop may have polarized the genny opposite from what it should be (hope if so the VR isnt fried)
My Troubleshootiong Procedure linked below can diagnose the cause.....and describe the ammeters polarity etc.
http://www.ytmag.com/cgi-bin/viewit.cgi?bd=jd&th=458743
John T
John Ts Troubleshooting
First thing Id do is try to re Polarize the genny n see what happens??????
Sure the ammeter is at the correct polarity and the battery was installd at right polarity matching the gennys polarity and the ammeters??? If the tractors not running and you switch on lights or ignition ammeter should swing to - discharge DOES YOURS??? If not either battery polarity has been reversed or ammeter needs its leads swapped. AGAIN RE POLARIZE THE GENNY N SEE WHAT HAPPENS and see if the battery is right and ammeter. The genny shop may have polarized the genny opposite from what it should be (hope if so the VR isnt fried)
My Troubleshootiong Procedure linked below can diagnose the cause.....and describe the ammeters polarity etc.
http://www.ytmag.com/cgi-bin/viewit.cgi?bd=jd&th=458743
John T
John Ts Troubleshooting
Bob M
Well-known Member
Your 400 came from the factory set up for positive ground. If the wiring at the ammeter was not changed when the tractor was switched to negative ground the problem is simple: The ammeter is now reading "backward".
The fix is easy - simply swap all the wires on the two ammeter posts.
You can verify whether the charging system is working taking a voltage reading across the battery with the engine running faster than 1/2 throttle. The voltage should be somewhere between about 13.5 and 14.5 volts.
The fix is easy - simply swap all the wires on the two ammeter posts.
You can verify whether the charging system is working taking a voltage reading across the battery with the engine running faster than 1/2 throttle. The voltage should be somewhere between about 13.5 and 14.5 volts.
Anonymous-0
Well-known Member
I polarized it by touching a wire between the battery and generator tab on the regulator it arked. the ampmeter reads negative -15 when running when I shut it down the ampmeter goes to + 30 on the guage.
Janicholson
Well-known Member
If it is charging when running (even though the gauge reads backwards) and indicates 30 amps discharge when shut off, You may have smoked the cutout relay in the VR. I hope it is disconnected now as that current will make more smoke if still connected. No system charges when shut off, so that is an indication that the gauge is connected backwards for sure. Taking the cover off the VR might let you see and release the stuck contacts.
Your polarization sounds correct, assuming the VR was hooked to the gen at the time. Jim
Your polarization sounds correct, assuming the VR was hooked to the gen at the time. Jim
YIKES I agree with Jimbo,,,,The VR's internal Cutout Relay must be sticking closed and as I stated earlier if the genny was at opposite polarity from the tractor at the shop and then you started it at the wrong polarity that can fry the VR!!!!!!! If you re polaried it BEFORE start up however, it should have been fine and all youre left with is a reversed ammeter but you need to unhook the battery if you havent already. If the cutout relay is stuck closed (should open when tractors shut down thereby disconnecting battery from genny) it will discharge high amps and if the belt were removed it would even sit there n spin the genny.
Hope the VR isnt trashed??????
John T
Hope the VR isnt trashed??????
John T
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