I am assembling a depot hack on a 1926 T chassis and drive train. Right now, I'm trying to figure out the wiring from the ignition switch to the generator. The wiring diagram I found shows a cut-out on the generator. Mine has none. Is the cut-out necessary? If not, how should the generator be connected to the ignition switch? The terminal appears to be connected to ground at present.
Tom: yes the cutout is necessary to keep the generator from trying to run like an electric motor when the engine is stopped and discharging the battery. The diode cutouts, available from many suppliers are a good replacement for the old originals. As far as the electrical diagram that you are referring to, I would look for a better one that is more accurate, the suppliers have these also. Brad.
I would recommend a Voltage Regulator from Fun Projects. I put one on my 26 pickup and can rest easy my generator will not self destruct.
One, if the generator is not properly connected with a cutout or other control, its output MUST be grounded, to keep it from burning itself up. It sounds like yours is, and that's good.
There are three kinds of "cutouts" available. All are little round cans that mount on top of the generator. Some are available with or without the FORD script embossed in the cover - your choice.
One, the original cutout. It is simply a switch that disconnects the generator when it isn't putting out juice, so as Brad says, it doesn't try to run like a motor and kill your battery. Its problem is, the output of the generator when the engine is running is not controlled, and depends on the setting of the third brush. If set too high, it can boil your battery on a long run.
Second, a "diode cutout." This is essentially the same as the mechanical, or original, cutout, except that it uses solid-state diodes instead of a mechanical relay. You won't have to worry about stuck relay contacts, but you still have full output at all times, whether needed or not.
Third, is the "Regulator." This is made by Fun Projects, who make several first-class parts and accessories for Model T's. It acts like the regulator in your modern car, in that it senses the amount of current needed to charge the battery, which diminishes to nearly zero as the battery becomes charged. Hence, no boil-over of the battery.
I believe the three I have described can be identified by their cost. Most of us pay for the third, to protect the battery. All are available from all the normal vendors.
Now, to the wiring.
Once the cutout or regulator is mounted and hooked up, trace the wire from it, and connect it to the same side of the ammeter as the short jumper to the ignition switch. How and where you make this connection depends on the length of the wire and where it terminates. That way, the charging activity of the generator will show as a "+" reading on the ammeter. You could connect it to the battery directly, but you'd have no indication of whether the generator is charging.
If the ammeter shows no charge, it may be that the generator is burned out (send it to Ron), or it could just need "flashing." You do this by momentarily connecting it directly to the battery, with the engine running. Don't do this with either the Diode or Regulator in the circuit!
Let us know how it turns out.
I noticed that Fun Projects lists several voltage regulators. Should I use a 6 or 12 volt battery? Why would there be an 8 volt regulator?
Tom, some guys do run 8V batteries with great success, I suspect that is why.
What voltage is the starter motor? In my youth, I put a 6-volt starter motor in a '56 Ford with a 12-volt system so it would start easier. It worked but I had to be careful not to burn it out.
I ordered a 12 regulator today for mine.Didn't need a ford script but I didn't see 1 without it in the Langs book. first time I have ordered parts from them.
You don't have to buy a diagram. This one's free.
I don't know why these guys put all this unnecessary crap on these posts! A stock T uses a 6 volt negative ground system. I like Johns new cutout. It works better than the old Ford one did. I only wish he would sell the internal assy., so I could spot weld my original cover to it.
Re; generator be connected to the ignition switch?
The wire to the generator is HOT at all times unless the battery is disconnected. Same with power to the lights and horn. All the ignition switch does is turn the car on and off and switch between magneto and battery for the ignition.
I recently rebuilt my original generator. Have never had a generator on a T and didn't understand how they worked within the electrical system until two months ago. Read the MTFC publication on electrical systems and three vintage books on starters and generators and felt confident enough to do the work. I also installed the Fun Projects voltage regulator.
So far everything seems to be charging and working as required. I drive my six volt system model T every single day ... unless it's raining (don't have the top restored yet) and am putting at least 100 miles a week on the car. Every morning when I step on the starter ... it roars to life on magneto within three cycles of the crank.
Larry, If you want an original looking voltage regulator, send an original Ford script cutout to John at Fun Projects, and he will install his regulator in it. He has an extra charge for doing this.
I have a nice original 1922 coupe that had a new shiny cutout on it when I got it. I wanted the regulator to match the "patina" like the rest of the car, so John put one of his regulators into an old Ford script cutout.
Personally, I am constantly thankful for the myriad answers and information that this forum has provided to me over the years. This hobby keeps me from becoming old and bitter, but it doesn't work for everyone.
Welcome to the forum! And good luck with your project. There are lots of well meaning folks here ready to help.
All this information is really helpful. Here's another question: How do I tell if my generator and starter are 6 or 12 volts?
They came from the factory as 6 volts. If they've been changed, then the battery would have been changed, too. But then, the light bulbs would have been changed, too. If you're not sure, try powering a bulb on 6 volts, and see how bright it gets. If yellow and dim, it's probably a 12 volt bulb.
All in all, the chances of both the starter and generator having been changed to 12 volts are slim.
One of the consistent threads on this Forum has to do with changing a Model T to 12 volts, to increase the cranking speed. Almost always, doing so is a band-aid, done to work around the real problem (like putting on a water pump because the radiator is in need of work).
A Model T engine cranks just fine and runs just fine on 6 volts, IF (and this is a big IF) all the cables are the right size and the connections are clean, bright, and tight. Oh, and if the start switch is in good condition, which is why many of us install a solenoid.
Save some potential heartache add a fuse between battery positive and the yellow positive voltage feed wire at the hot side of the starter switch, this would be location G in the diagram Steve Jelf provided. A 15 or 20 amp fuse will work, fun projects makes a kit for this also or can be found at any auto supply. I have sourced mine from old accessory wiring harnesses such as MICKEY MOUSE remote start kits I had removed from modern cars
I have no idea what components, if any, have been changed as this came in pieces with more assembly than expected required. I have the cans for the headlights but none of the inside works and no wiring under the hood except for the distributor to the coil and to the spark plugs. I unsuccessfully attempted to attach photos of the battery (which I think may be 12 v) which was thrown in with the deal and may not be right for the car and the generator.
I am at a loss as how to attach a regulator to the generator because Fun's directions refer to the cut-out, which I don't have.
Your generator will put out any amount of volts you want...right up to infinity and destruction of the armature...
It is your choice of cutout (6V, 8V, 12V) that determines when the generator will be allowed to start sending to the battery...so, you see where I'm going with this...you buy the battery, 6, 8, 12, and a matching cutout. Wire it for negative ground, and if the generator is functional, all will be well with the world.
Model T's will start and run just fine on 6V as designed, so if you go to higher voltage, let it be your choice and not someone else's insistence that it is necessary.
There will be two screw holes on the top of the generator, this is where the cut out/regulator mounts. DO not use the wrong screws here, if they are too long they will press into the field windings and short them out. Does not matter what type cut out/regulator you mount they go in the same place and often the term cut out is used for both.
If you just want to run the engine without the cut out/regulator, run a jumper wire from the output terminal to ground and wrap hot wire with tape prevent shorting.
There have been numerous posts demonstrating that a properly adjusted T engine will start at ridiculously slow cranking speeds - including no cranking at all if the engine is warm - the famous "free start". I don't have anything against 8 or 12 Volt conversions, but as Peter said, it is usually a band-aid to cover another problem. The only reason I would convert a T to 12 volts would be if I wanted a modern stereo or air conditioning system. I don't.
6 volt battery will have 3 filler caps the 12 volt has 6.
If you don't have a copy yet I suggest getting the Ford Service Manual. I is full of good information on repair and maintenance. Also a copy of the owners manual, it has a section that covers questions like this and how to drive the car.
It's good to ask questions here but sometimes is faster to have book at hand.
By shining more light on the generator I found the two screw holes. What size screws do they take? How is the magneto wire attached to the terminal at the top of the hogshead? Mine doesn't have a nut. Is it supposed to? If so, what size?
backorder on my regulator.I aint in a big hurry for it though. Hopefully sometime by january as that is my goal for getting the body on the chassis.