voltage regulator

I have a 1949 jd m crawler. i ordered a new voltage regulator and it was different. it turns out that it is a real regulator and not just a cut out relay. this web site shows how to wire it under the three wire generator section. the regulator has a extra post with a (L) on it. what is that for? is that for a low charge light indicator( like in a car ). also if i understand this correctly i will no longer need the resister wiring on the ignition switch? thanks derek

Okay, it is possible to convert an old Cutout Relay that used a Manual Low/High light switch charge control over to a full fledged Voltage Regulator but this is NOT going to be a perfect original genny to control system conversion BUT I'VE DONE IT AND IT CAN WORK. In the old original days the VR was matched to deliver the correct amperage to match the gennys Field windings specs/rating ya know. If the genny has a third adjustable brush when I made this conversion I usually adjusted the third brush to the max charge location.

WIRE THE NEW VR AS FOLLOWS

BAT up to Load (NOT battery/starter) side of
the ammeter. Thats the side that used to wire
to BAT on the Cutout Relay

ARM to Gennys ARM post

FLD to Gennys FLD Post. NOTE FLD on Genny used
to wire to light switch but you dont do that
now, Gennys FLD now wires to VR instead

LOAD feeds battery voltage to loads like lights and ignition (via their switches). In the old system those loads were fed instead off the load side of the ammeter (same place that wired to BAT on CR) but if you convert you feed them instead from L on the VR. NOTE it will still work if you dont do this and leave them fed from the ammeter.

The VR has to be suitable for the Tractors ground which was originally POS ground. Be sure the Genny is polarized correct before start up or you could fry the new VR.

Got it???

PS if the VR accidentally overloads and overheats the gennys field windings dont blame me, but if its a 6 volt VR suitable for the tractors ground it will most likely be okay

John T

Derek
The "L" is simply another place to wire up loads ( lights )with out hooking them to the key switch or amp meter. As for the resister , the original system was 6 volt and does not show it on the old diagrams that eye can see. Although their is a fuse between the amp meter and the key switch to protect the lighting circuit. If in fact the electrical system has been change to 12 volt and their is a resistor between the key switch and the coil it should remain unless the coil has been changed to a 12 volt which may or may not require it, some new coils state No External Resistor Required printed on them. Hope this helps..
Jo

Derek
Please disreguard MY post. I do not know what I was thinking. I was reading it as three wire delco alternator . John T has you covered.
Jo

I forgot to address one part of your question:

"also if i understand this correctly i will no longer need the resister wiring on the ignition switch?"

Heres the deal:

A) If theres a resistor (often an open spiral coil of bigger wire) on the switch used to control Bright or Dim lights?? THAT IS STILL USED FOR BRIGHT OR DIM LIGHT CONTROL IF THE SWITCH IS SO EQUIPPED (Sorry I dont have any M's to look at and cant recall if they had a dim/bright light switch)

B) If theres a flat wound coil of smaller wire, thats more likely the Low/High Field control resistor used to regulate charge to High (resistor by passed) or Low (resistor in series with terminal to FLD on genny) AND WITH A VOLTAGE REGULATOR NONE OF THAT OR THE WIRE FROM THERE DOWN TO THE GENNY WILL BE USED

A typical low high charge control resistor is flat wound and may be like 2 to 4 ohms and it will have continuity in the terminal that wires to FLD on genny to the case ground. In LOW the terminal that goes from the switch down to genny would be around 2 to 4 ohms but in HIGH it should be near 0 ohms from that terminal to case ground.

A typical lighting dim/bright resistor is much less in ohms and is heavier wire and is in the circuit that leads to the lights

You DID NOT mention 12 volt conversion or any ignition ballast resistor so if you have such and have questiosn post back. Originally it was 6 volts and a 6 volt coil so theres no external ignition ballast resistor. if its 12 volts you need either a 12 volt coil or the old 6 volt PLUS an ignition ballast BUT NONE OF THAT HAS TO DO WITH LIGHT OR CHARGE CONTROL RESISTORS ALREADY ON THE SWITCH

Now this plus my post below should answer your questions

John T

The L post will give you a few more amps for winter charging. Other than that it isn't used. You will be removing the field wire from the switch resistor and putting it on the regulator. The resistor won't be in the circuit(just go's to ground anyway) after you remove the wire so just leave the resistor alone.