M charging rate

Our '49 M's generator just won't charge enough to be able to run the lights and maintain a positive charge rate...even at wide open throttle. Maximum charge shown on ammeter with no load is around 5-6 amps at WOT with light switch selector set at "H" and cuts back to 2-3 amps after tractor has run for maybe 1/2 hour or so. This tractor has a voltage regulator, not a cutout, mounted on top of the generator. Any help sincerely appreciated.

The third brush is adjustable. Moving it closer to the insulated brush will increase output. There should be a screw on the back plate that you need to loosen so that the brush can be moved. All this is assuming that the charging system is in good shape. Chuck

If you have a voltage regulator, the high and low on the light switch are inoperative. Perhaps you can adjust the third brush on the generator and/or increase the spring tension on the voltage regulator to get about 7.3 volts at the battery.

Try temporarily grounding the generator field (ground the F terminal on the regulator or generator, whichever is handiest). Now run the engine wide open. You should enough amps to run the lights and have 3 - 5 amps left over and charging the battery.

If you get the above with the F terminal grounded the problem is the voltage regulator - it's time to replace it.

However if there's no improvement with the field grounded it's the the generator that needs attention. It could be as simple as the 3rd brush needs adjustment (move it closer to the nearest fixed brush to increase output).

Or it could have worn out brushes, a bad commutator, a shorted winding in the armature, etc. If that's the case a visit to your friendly local starter/alternator shop is recommended!

Wellllllllll if it reallyyyyyyyyyy has a Voltge Regulator versus using the old cutout relay and LHBD light switch charge controller IT, NOT THE LHBD LIGHT SWITCH SHOULD BE CONTROLLING THE CHARGE AND THE GENNYS FLD POST SHOULDNT EVEN BE WIRED TO THE SWITCH BUT FLD ON THE VR. Maybe you have it wired wrong if it was converted???

Its not one of the older cutout relays that has an F terminal is it??? I doubt it if it has the LHBD light switch

Sure its wired right and using the VR?? If its a VR and wired correct, the LHBD shoultn have any affect on charging.

1) See if the Gennys FLD post is wired to FLD on the VR or goes up to the LHBD switch??? If its a VR, the gennys ARM goes to the VR ARM/GEN,,,,,,FLD on VR to gennys FLD post,,,,,BAT on VR up to ammeter.

2) If its just a cutout relay the gennys FLD then indeed wires up to the LHBD switch AND THAT WIRE NEEDS TO BE GOOD PLUS THE SWITCH NEEDS A GOOD SOLID GROUND otherwise it wont charge at any high rate

MAKE SURE THE BELT IS GOOD N TIGHT AND THAT THE GENNY,,,,,,,,THE VR OR RELAY,,,,,,,AND ESPECIALLY THE LIGHT SWITCH ALLLLLLLLL HAVE GOOD GROUNDS

TROUBLESHOOT:: When shes running at fast RPM take a jumper and dead ground the gennys FLD post to a good ground n see how she charges cuz that makes her full charge REGARDLESS if its a VR or relay

Ifffffffff it charges more then but NOT otherwise, the problems EITHER a bad ground on the switch (if its being used versus VR),,,,,or the switch is bad,,,,,, or the VR dont have a good ground (if it uses a VR that is),,,,,,,,or it has a VR but its bad.

But Ifffffffff the charge is still weak and the belt is good,,,,,,and the Gennys FLD post is dead grounded,,,,,,,,,then Id say the gennys itself is weak or the battery is bad.......

When converting a 3 brush genny over to a VR system Id set the adjustable third brush to the high charge rate otherwise she may never charge at a good rate, wheres yours set????

Check the wiring (determine if a VR or cutout and LHBD use and if its wired correct as above for either system) ,,,,,,,,,,,,,check the Genny and VR for a good ground and the LHBD ground (if it uses that),,,,,,,,,,check the belt,,,,,,,,,,,,,,,,see how she charges with the gennys FLD post dead to ground cuz thats max high charge REGARDLESS what system it has,,,,,,,if still slow charge even with a good dead FLD to ground and Gennys has a good ground see if the third brush can be set higher (move closet to fixed brush beside it),,,,,,,,IF STILL A WEAK CHARGE I SUSPECT THE GENNY IS BAD OR SHES (genny and VR and switch) NOT WIRED RIGHT or the belt is bad or a bad battery

John T