I just got an older Allis Chalmers track loader and found that it has a 24V electrical system on it (2 - 12V batteries in series) but the 24V generator is gone and it has been adapted to mount an alternator. Both the 24V starter and 12V alternator that are on it need work and currently there is no charging system wiring in place.

My question is:
- Should I try to find a 12V starter for this diesel loader or
- Should I find a way to make the 12V alternator charge the batteries thru some sort of series/parallel switch and leave the starter at 24V?

Any suggestions? The engine is purely mechanical so no electrical is needed there except for the starter. The only other electrical is the headlights which currently are 24V but can be changed.

 

12Valve
If the batteries are wired series + to + - to - then you are running a 12v system. so a single wire alt would charge the batteries ok. so go with the alt.
Danny

 

The 12V alternator will put out 24V if you get an external regulator that will work with it. The way the regulator works with an alternator is the armature field is varied to adjust the output voltage so a 24V regulator would work fine. Finding it would be the problem. Check around at places that cater to vehicles with 24V systems.

If the alt has a built in regulator it might be a problem though.

In the past there were boxes you could attach to your car alternator to get them to produce 110V for running power tools. Just flip a switch and you had 110V at the outlet on the box. The battery wouldn't charge though so for extended running it could become a problem. I used one a lot when I was doing service work installing two-way radios in vehicles.

Edwin

 

Koonster,

They aren’t. They're wired + to - in series for a total of 24V output to the starter and lights. Thus the question of whether to totally change to 12V by finding (if I can) a 12V starter or building a hybrid electrical system with a series/parallel switch to charge from the 12V single-wire alternator but start from 24V.


Thanks for the response.

 

12valve@heart:
24volt alternators aren't all THAT rare... A good alternator shop should know about them and either can mix or match the right regulator parts for a 24volt output unit, or you should be able to buy a 24volt reman alt from a heavy equip supplier for not THAT much money...
The alternators on our big Cummins powered emerg generators have normal sized, Motorola made, 24volt, single wire standalone alternators installed under the fan guards.

My question on the trackloader, how many OTHER things are 24volt only??
(hydraulic control solenoids, fuel pumps,dash instrumentation, heater blower motors, windshield wiper motors etc?...)
If these are all 12volt, it is a very good possiblity this thing is a 24volt start-12v run system.. I've seen them used on hard to start hotrod engines, but never messed with them myself.
They used a special multi-pole solenoid type starting relay that when energized puts the batts in series for the starter motor only and returns to 12v parallel for charging and running the rest of the vehicle...
If there is quite a bit of 24volt stuff, it would probably be cheaper to just procure a 24volt reman alternator than convert to all 12volt..


Good luck
Keith

 

Or find a shop that can rebuild your old one.

If it's a generator, the brushes could just be worn out.

 

Thanks for the replys guys.

This is a '62 model that has almost no electrical on it. From my looking at it, the only things electrical that I've found are the starter, alternator/generator, headlights, and amp gauge. All other controls are mechanical so converting to 12V should be easy if I can find a 12V starter. This starter just toasted the solonoid and bendix but I plan to check the brushes while I have it off. If it weren't an issue of traction, I'd just pull-start it and forget the electrical but my truck can't get that 13 ton beast moving with its bucket dragging the ground and it sure is hard to pull-start something when you're working by yourself. I pulled it off the semi when it arrived but it was tire-spin city even with the bucket in the air. I'm stopping by the starter shop tomorrow to see what they tell me.

 

sorry, don't want to hijack threadbut, Will a set of lights that are off a 24 volt system, work on a 12volt system? how about 12volt lights to a 24 volt sytem?

 

DUH, the 24 volt lights will be dim on 12V. The 12V lights will be very bright for a short time, maybe milliseconds.

Edwin

 

Two 12V lights can be connected in series on a 24V system and will function normally. The old GMC buses and trucks used to do that. Problem is, they function like Christmas tree lights - one goes out and they both go out.

 

This is only true if the bulbs are the same wattage. If not the lower watt bulb will be extra bright and the higher watt bulb will be dim.

Edwin