Help identifying voltage regulator poles

If it was originally a 4 pole VR, the hot voltage feed for Loads like lights and Ignition was suppled from the L terminal on a 4 pole VR. HOWEVER if you wanna use that 3 pole VR, the voltage feed for Lights and Ignition (what used to wire to L on a 4 pole VR) can then be fed off the VR's BAT terminal instead or else directly up behind the dash by a wire off the ammeters load side terminal, being the SAME terminal that wires to the BAT terminal on a VR (3 or 4 pole). If the wiring harness was originally for a 4 pole VR with TWO not just one wires up to the dash, just conenct the load wire (feeds lights n ignition) over to BAT on the VR since theres no L terminal to hook to on your 3 pole VR

WITH THE VR STANDING ALONE NOT CONNECTED TO NUTTIN

Now as far as those unlabeled terminals, one of them (the FLD terminal) should show very low resistance between it and the VR's metal mounting case/frame. If you find which terminal shows low or no resistance to the metallic case where she mounts, label it Field (FLD) and it wires to the Field post on the Genny.

The other 2 terminals would be BAT and ARM (or GEN) and there should be an like a very high (Open) resistance measured between them. Between those 2 terminals (BAT and GEN/ARM) theres a Cutout Relay which is normally in the open (or very high resistance) position but once the gennys output voltage rises higher then battery voltage, the relay closes so the gennys output (its ARM terminal) can get to n be connected with n charge the battery (out the VR's BAT terminal) but when the tractors shut down that Cutout Relay (between BAT and ARM/GEN VR terminals) opens so the battery dont reverse discharge through the genny. Soooo just sittin there not hooked to nuttin the Cutout Relay should be in the OPEN position (very high resistance) since it shouldnt close until it senses voltage on the ARM/GEN terminal.

BAT on VR wires to the ammeters Load side terminal

FLD on VR wires to the gennys Field post

ARM/GEN on VR wires to gennys Arm post

Loads like lights n ignition wire to the BAT terminal on a 3 pole VR or else the ammeters load side terminal being the same terminal that wires to BAT on the VR.

NOTE N CAUTION one thing confusing is did you mean theres only one coil/relay inside the unit????? ????? Cuz a simple Cutout Relay has but one coil/relay inside,,,,, ,, while a VR (3 or 4 pole) has at least 2 n sometimes 3 coil/relays inside. Also on some simple cutout relays, theres still only one coil/relay inside although they have an extra 3rd lil external terminal. The simple cutout relays used the light switch (L H B D) as the field curent control system by having the gennys Field post wire to the light switch instead of any FLD terminal like on the VR syatems. I cant tell sitting here what you really have, a simple Cutout Relay or a VR, so Im hesitant to describe the wiring buttttt tt if theres only one coil/relay inside it Ima thinkin it a simple Cutout Relay..... .....

Maybe digest all this n look closely at the VR or Relay or whatever it is you have and tell us more or if we had pics n we will go from there. NOTE Bob M and Bob are more familiar with this IHC stuff then me (Im a John Deere man) since I havent owned them for years so if they tell you different then me believe them buttttt t as far as I know still alllll lll I posted above is accurate, they may have more IHC cutout relays or VR's laying around (I have NONE) to look at n compare n guide you better then me cuz sorry, I just cant tell from sittin here not seeing or knowing any resistance values or how many coil/relays are inside that unit to know what you really have, maybe they can????? ???

Best wishes n God Bless yall, sorry no definite answer here but the above may still help figure it out

John T

F (or FLD) – ~0 ohms
G (or GEN) – several ohms
B (or BAT) - open circuit (infinity)

Obviously the remaining terminal will be the L.

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Additional tests:

1 - Remove the regulator cover. You should find two relays inside.

2 - Attach one test lead to the regulator base and connect the other to the F terminal. Now push the voltage regulator relay armature down (the voltage regulator is the relay whose contacts are held SHUT by spring pressure). The meter should read several tenths of an ohm with the contacts held manually open.

4 - Connect one test lead to G terminal and the other to the B terminal. The ohmmeter should indicate open circuit. Now manually push the cutout relay down (the cutout's the the relay whose contacts are held OPEN by spring pressure). The meter should read ~0 ohms with the cutout contacts held manually closed.

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Note: It's possible your regulator has only 3 terminals (ie. the L is missing). If so simply connect the ”orphaned” wiring harness L wire to the B (or BAT) terminal on the regulator.

Hope this helps...

John T

Answer would be it's a simple cutout. That could explain why it's got only 3 terminals.

However since the 300U came equipped from the factory with a 4-terminal voltage regulator, finding a cutout would mean Matt's got the wrong part installed on his tractor!

Thanks for mentioning! ...Bob M

ok