The Fordson Tractor Pages Forum

Hi i havea question about an alternator charging system on my 1959 power major. My tractor currently doesnt charge the battery. I was wondering which vehicle alternator would mount to this tractor without much modification?

The older the better... The pulley will be the difficult bit I would think, most modern alternators have a wide pulley for a multi-ribbed belt, and you would need to swap this to a 'V'.

My own Major came fitted with an alternator, I've never looked to see what make it is, but it has the original Major pulley fitted, which is far too big; the charging light doesn't go out until the engine is at near full revs. The alternator needs to spin much faster than a dynamo. For normal tiddling about I don't bother if the light is on, it keeps the battery up with an occasional period of charging while discing etc - and at the moment I have no working headlights, radio, or anything to use electric

In your position I would seriously consider finding out what's wrong with your dynamo, regulator, or wiring - it would be easier to fix that!

IIRC you will probably need to convert the tractor from positive to negative earth to use an alternator instead of a dynamo - not too terrible given the limited wiring but may be easier to just find your existing fault like Bob suggests as you will have to do that anyway..........

I got an altenator off ebay, sold as fitting all majors then spent half a day making various brackets trying to get it to fit, gave up and returned it. They offered me a fitting kit ( no mention of that in the listing ) which included a flush fitting plug to replace the block drain tap. Told me I was the first person unable to fit the altenator but when I checked the listing it said 1 sold - well I suppose he wasn`t really telling porkies. In fairness they did change the listing afterwards.
My son told me it was a common type altenator which fits the old type minis and it was much cheaper at a motor factors. I got a dynamo off Agriline and it was a straight swop and worked.

Could someone have hooked up the battery backwards on my tractor maybe? The positive post goes to the solenoid and the negative is grounded to the frame? Could it be possible that they hooked it up backwards and its not charging?

It should charge either way, with positive or negative earth, although there is a procedure for changing from one to the other... quickly touching one of the dynamo terminals with a live wire? It used to be done on old Minis and Morris Minors (which were positive-earth from the factory) so that a radio could be fitted (which needed negative-earth). I've never done it myself, I never had a radio in my Mini, but I'm sure someone old should know.
But yes, that could be your problem - although I think they can often sort themselves out anyway?

The dynamo uses residual magnetism to start charging initially, until the field coils kick in, the 'flashing' Bob describes can sometimes be needed to re establish this magnetism. Put flashing dynamo in the search box top right here and it will bring up a number of useful past postings.

The other problem may be in the regulator (behind the ammeter / oil pressure gauge), if it doesn't feed current back to the small terminal on the dynamo then you will get no charging from it.

Have a quiet read round the old posts which will explain what should happen and how to check and repair so you can get your head round it, even if you are not naturally 'electrical' one bit at a time should get you through

oehrick wrote:The dynamo uses residual magnetism to start charging initially, until the field coils kick in, the 'flashing' Bob describes can sometimes be needed to re establish this magnetism. Put flashing dynamo in the search box top right here and it will bring up a number of useful past postings.

The other problem may be in the regulator (behind the ammeter / oil pressure gauge), if it doesn't feed current back to the small terminal on the dynamo then you will get no charging from it.

Have a quiet read round the old posts which will explain what should happen and how to check and repair so you can get your head round it, even if you are not naturally 'electrical' one bit at a time should get you through

Hi oerick/scottyboy
if he has a genuine un messed with power major and doesn't want to fit the alternator he doesn't have the tin box with the switch/ gauges and regulator in under the fuel tank like the tractors before the power/super majors. He's got a 3 sided steel plate with the combined ignition key/ light switch. a stop cable then the high low range lever pokes through it on the R/H side.

He should have his gauges mounted just under the steering wheel in a tin housing on top of the tank round the steering column. there should be an oil light/ charge light, temp gauge in one assembled unit on the left. then on the right a rev counter and the hand throttle . His regulator should be mounted up under the bonnet by the air cleaner canister.
I'm sure the power major regulator is on the battery tray by the starter solenoid bracket( been a while since I looked mine), with a blue tin cover over it if it hasn't fallen off. If it's an original regulator it 's made from black Bakelite plastic type stuff. not aluminium like the later super major ones.

If the batterys connected wrong that won't help. The old fordson switches were hopeless for poor connections internally 35 + years ago when my dad farmed with these tractors. as for the dynamo and regulator who knows. and the same for the wiring. To be honest I've owned power majors and supers where the wires that run up through the steering box tube to the dash panel and warning lights, Are a fire hazard looking for an accident.

You really need to go through the whole wiring and components to check everything's right. There is a super major sitting about 20 miles from here had a wiring fire from a short, it really didn't help the tractor and 15 acres of land when the smoke and fire genie escaped.
simply don't skimp on the electrics it's a shame to burn a good tractor.
Regards Robert

Thanks for the correction Robert, I had it in mind the Power was the same as my Mk2 and that the steering shaft instrument cluster arrived with the Super

Hi im curious now. My gauges are all smashed is there a good cheap source for them? Im going on a guess that its not charging according to the previous owner. Is there any way to just hook up a cheap amp meter? Im pretty lost when it comes to wiring.

use a volt meter on the battery + and -. if the voltage is going up, it's charging the battery.