Allis chalmers c cut out

[Dustin Hartmann]

I have a 1942 Allis chalmers c that i compleaty restored just finshed last summer.I turned on the lights and it blew both bulbs so i chcked the voltage and it said 8 volts. Is the the cut out acting up the genrator was rebulit but it is the orignal 1942 cut out. the cut out was ruff inside the cut out. but it was working at the time. what else could it be

 

[George R. (MN)]

Dustin,

Sounds to me like the tractor has been converted to 12 volts. If so you will need to change to 12v bulbs. If it is still a 6v system it could be the light switch is bad. For the charging system to work properly you need the original style three position resistor switch. Also, check to see that you have a good ground at the control box, battery, starter and generator.

Good luck, George

 

[Bob]

7.4 Volts IS a normal charging voltage for a "6-Volt" battery, so 8 Volts isn't far enough off that it should be instantly zapping bulbs.

 

[Dustin Hartmann]

nope it is still 6 volts.

 

[John T]

If that 8 volts you measured was on the battery, the cutout is working although 8 may be a tad on the high side, Id expect more like 6.5 to 7.5 volts or so max. Try it when shes NOT running n see if the bulbs glow realllll bright just momentarily then blow out??????????

I take it you have a 6 volt battery but wonder as posted below the genny is a 12 volt?? If so Id expect the battery voltage to rise higher then the more normal 6.5 to 7 and the lights would blow out when shes runing but NOT if shes just setting, assuming a 6 volt battery but a 12 volt genny.

If its a 12 volt converion you may have some other ignition issues like an ignition ballast may be needed or a 12 volt coil to be installed.

John T

 

[Dustin Hartmann]

Everthing on the tractor is 6 volt including genrator

 

[Dustin Hartmann]

it also has the correct light switvh

 

[steve(ill)]

a 6 volt generator can put out about 12-15 volts if you pull the cable off the battery. the battery acts as a "sink" and keeps the charge down to 7- 7.4 as the guys said... summary is the battery could be very low and need a deep charge, or the wire from ampmeter to battery is loose or corroded and the generator is overcharning (voltage wise). the power to the lights probably come off the generator side and not directly off the battery cable... i think i would start the tractor, turn on the light switch, and use a volt meter to see what is available at the head light wire- to ground. then let tractor charge for 20 minutes and see if it drops, or stays the same.

 

[John T]

Sounds like we BOTH would sure like to know just where he is measuring that voltage, on the battery or genny if its NOT properly attached to the battery. The open unloaded voltage output of a genny can raise a good deal higher then when attached to a GOOD battery as you noted.

Hmmmmmmmm lol

JOhn T

 

[Anonymous-0]

OK, I'll chime in...batteries can do what called "sulfating"...where a build up starts to form on the anodes of one or more cells. This effect sometimes reduces output current and increases charge voltage. That COULD be why you're getting 8 volts...only way to tell is swap out the battery unless you have an auto shop quality tester.

I think that the light deal may have been a fluke. Did ya check the voltage at the light socket to see? Analog meter is better for this cause it'll show a momentary jump in volts due to a flakey switch...a digital meter won't.

It'd take alot more than 8volts to instantly blow both bulbs. 8 volts would just make them nice and bright. Have to be more like 12volts.

John gave you alot of good advise too. This is the stuff that takes alot of patience when working on the old iron...