Voltage Regulator Problem

WayneMo · Sep 23, 2011

My friends farmall a has a problem with his regulator, the ammeter just wiggles wildly back and forth but the voltage is 7.5v which is good. One of the relays is switching in and out slowly which is causing the wild ammeter fluctuations.
Which relay is the cutout and which is the voltage relay? The relay towards the front of the tractor or the one toward the rear? How can you identify them? The front one has an upper stop for the contact arm while the rear does not.

John T · Sep 23, 2011

The relay that has that big fat coil/winding is the Cutout and one of its leads wires to the BAT terminal and another to the ARM/GEN. The Voltage/Curent control relay has smaller coil/windings and one leads to the FLD terminal.

The VR cant work right unless it has a good clean ground

If the gennys commutator is carboned or oiled up or if the brushes are worn down short there can be excess sparking and a jumpy ammeter i.e the genny may be the problem instead of the VR

If the relay contacts are burned/pitted/carboned that can also cause problems.

Ive seen ammeters that are bad and jumpy when all else is okay!!!!

By pass the VR altogether and see what the ammeter does??? To do that when shes running temporarily dead ground the gennys FLD post which takes the control relay out of the picture n see what happens??????? Then temporarily by pass jump around the cutout relay by wiring BAT over to the ARM terminal n see what she does while shes running??? If she charges good n smooth n steady while the VR is by passed but not otherwise, the gennys is okay so its a VR or bad grounded VR problem

John T

Voltage Regulator Problem

WayneMo

Member

John T

Well-known Member

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