Speaking of Regulators........

[amtrac]

Some time ago I started a thread about why my Cub's coil gets so hot that the engine will quit. It was suggested by someone that I should only be getting 7.2 Volts from the generator to the battery and no more. Any more voltage than that will cook a 6V coil so the gentleman said. So, I rigged up a temporary volt meter to the tractor and look what I got! Looks to me like my regulator is not cutting off at the proper voltage. My question is: Can this type of regulator be adjusted? New coil and new VR from Brillmans last year.

 

[John T]

A fully charged and good 6 volt battery at rest and stabilized should measure around
6.3 Volts. Under charge subject to RPM Genny and VR it should rise to at least 6.5 up
to around 7+ Volts. Thats more typical on an old tractor and genny

I wouldnt expect a true 6 volt coil (sure thats what you have ???) to instantly fry
if it were exposed to as high as 8 volts over a short term, maybe if it saw say 7.9
to 8.5 long enough it could eventually overheat but there are many variables such as
ambient temp, its location, etc etc hard to say from here too many unknowns.....

NOTE I will say if a 6 volt battery is charged at 8.4 volts for a long enough time
IT MAY OVERCHARGE AND/OR BOIL OUT EXCESS ACID Again 6.5 to 7+ Volts is what I
suggest.

YES a VR can be adjusted but it takes know how and good instruments I do NOT offer
advice how to over the net, some here may do so

John T

 

[amtrac]

John T., Yes, the coil is 6V. Brillman Co. has the type of coil used on the old Cub engines. Fits inside the bracket and the terminals are on the opposite end of the primary wire going to the distributor, just like the originals. Question: Does the third brush in the genny have anything to do with voltage? I wish I could fit a 6V alternator in there and do away with the genny/VR. There's not much room under the hood of a Cub. Tractor will run maybe 45 minutes before trouble starts. I have not seen any problems with the battery......yet. Thanks, Ron

 

[jimtrs]

There are many things that could be affecting the output of your generator. Wiring, grounds, battery condition, field circuit / resistance.

You obviously are having a problem with the coil overheating. Just to clarify, voltage does not overheat a coil, amperage does. Amperage is determined by using ohms law. While voltage is one factor of ohms law, resistance is another. On these old tractors anything can have been done. Yours may or may not have a light switch which can full ground the field circuit. While this switch was primarily used on generators with cutouts, I have seen them with voltage regulators. High charge position of this switch will put the generator into high charge mode, and absolutely cannot be run constantly at this level. I have seen some that have melted the solder in the generator.
A battery on it's way out, or not healthy can cause a generator to put out max amperage.
Fields and/or wires shorting out can put it in max output. A generator in max output can be showing high voltage along with high amperage. Again, it's the amperage that is heating things up.
Would be worthwhile to have the generator and regulator tested together, by a competent automotive electric shop (generator / alternator rebuilder)

 

[gene bender]

IS your regulator made for the gen you are using very important that they are made for each other looking at your regulator i
would say your generator is a 1101501 the earlier CUBS used a 1101355 or a 1101423 those used a cutout on top of the genny but
there are regulators made for them

 

[John T]

Question: Does the third brush in the genny have anything to do with voltage?

YES: A third adjustable brush increases a gennys output the closer its moved to the fixed (NON grounded) brush right next to it as it increases field current that strengthens the magnetic field in which the armature rotates.........Sorry if thats too technical, that's just how Im wired its in my DNA lol

Ask the Farmall guys maybe Hitachi makes a smaller alternator but they are prob 12 volts only ?? You may have to change to 12. Again 8.4 volts IS TOO HIGH and I can see a coil overheating..plus the battery can get overcharged and/or boil over

Id get that over voltage fixed (if 8.4 is accurate) then the coil would be okay but who or how to adjust the VR (may involve springs and tabs etc janicholson or Bob M may be able to help not me) ?????? If possible try moving an adjustable third brush FURTHER AWAY from the brush next to it, that's easy peasey

John T

 

[J.Wondergem]

Seems as though the new voltage regulators come set NOT to work. the last one that I bought wouldn't charge at all. Took the cover off and it had at least 1/8 inch gap in the main points I adjusted it to 20 thousands and it works, but jumps from charge to no charge, back and forth. I guess I need to adjust the other gap too. I haven't got around to try that yet.

 

[amtrac]

Thanks to everyone trying to help. I think I will try to adjust the third brush. If that does not remedy the problem, I think I will have to take my problem tractor to the generator/alternator/starter shop. Ron

 

[John M]

Ill bet you money youll adjust that 3rd brush and it will still get hot. You need a coil. IIRC you
have an 8volt battery?

 

[amtrac]

(quoted from post at 08:17:25 05/14/23) Ill bet you money youll adjust that 3rd brush and it will still get hot. You need a coil. IIRC you
have an 8volt battery?

Very good John! It did have an 8V battery when I bought the tractor. Has been changed out to a new 6V battery since. Always wondered why the PO had an 8V battery in there. Maybe there was a reason back then because he was having the same problem. Ron