Hey all, is there a way to ID the cutout on my T's generator? Ideally I'd like to have one of the modern diode ones and what I have does look significantly newer than most of the car but is there a way to be sure?
If you do not wish to open it, a simple test is to connect it in series with a test lamp to a battery. If it's a diode cutout, the lamp will light when the cutout is connected in one direction and not the other. If it does not light at all then it's mechanical.
Note that this test won't differentiate between a diode cutout and a Fun Projects voltage regulator; to do that is a bit more involved without actually seeing it.
One sign of being mechanical is sometimes you can see a small gauge copper wire connected to the generator terminal underneath the cutout. This is one of the connections to the voltage coil.
A diode based cut out is lighter than the relay based unit. Usually the Fun Projects device has labels with a couple of warnings.
Thanks guys, I'll give that test a shot. I thought maybe I could give it the solid state shake test but the results were inconclusive.
Check if the cover comes off easily, if it comes off you can see if it's a diode or an electro-mechanical type.
The Fun Projects voltage regulator ones have the cover welded on
My cover looks to have four little pressed in dimples holding it together around the bottom edge and I'm fairly confident the cap is plated underneath the ugly blue paint someone sprayed on. Seems like I could maybe pry the cap off but I'm worried about bending something in the process.
Why the last guy thought the head and cutout should be blue is beyond me.
Here are comparisons, of each, from the underside.
The VR is the voltage regulator, and it has a tiny "V" shaped slit near the edge. In the photo this identifying slit is at the letter R.
I wouldn't rely on those pics for a positive ID for anything other than a FP VR.
Many electro-mechanical cutout's have been converted to diode by a PO so you don't know what's inside w/out removing the cover and eyeballing it.
If the cover's not welded on it's fairly easy to pop it off and look inside.
But one sure way is to weight it as Tony posted.
The mechanical guts of the points, coil and frame of a std. cutout will outweigh a diode cutout.
I deal with relay cutouts, VR's, diode conversions and new diode cutouts everyday and weighing them only tells what they weigh and absolutely nothing about the contents.
Ron the Coilman
Here is a photo of two original relay type cutouts.
The one on the left is a good quality unit made by Echlin from the 1930's. This unit will work well, but in the long run arching at the contacts will finally cause it to fail with the contacts either stuck closed or fail to close. In the former case, if not discovered, it will completely deplete the battery and ruining it if left that way for too long, which is usually the case. In the later case (cutout contact not closing) driving the car with the cutout not connecting the generator to the battery will result in the Model T Third Brush regulation generator destroying itself.
The one on the right is the very poor quality relay cutout unit made and sold by one Model T parts supplier and, unfortunately, supplied to many other parts vendors. These units do not last very long in operational service. The failure results are the same only faster.
Ron the Coilman
Thanks guys, I should just bite the bullet and tear mine open, or at least post pics. So far nothing posted quite matches mine. Without having it in my hand right now, I remember I have a wide strip of some sort of resin-based board whether phenolic or something more modern across the bottom I guess to insulate fasteners or something.
Photos would be best first.
Ron the Coilman
You have one probably made by United Technologies. They made them with a bakelite insulation for the terminals. On the quality scale they would fit between the 2 versions that Ron posted pictures of. Please heed the warning that ALL mechanical cutouts fail and when they do they usually take either the battery or generator with them and many times both.
I make the VR unit but even if you don't buy my thing - don't run a good generator/battery combination into the ground by using a mechanical cutout. They are nasty. Modify your own cutout to a diode type if you know how but then do not set your charge rate higher than 5 amps with the lights OFF or you will overcharge your battery. I will let others advise you as to whether you should use a VR or not. It mainly depends on how often you drive your T and how long each trip is. If you only use it in a parade once or twice a year then a cutout is probably OK but NOT a mechanical one since they can destroy your generator in a very short time even during one parade.
I would use nothing but one of John's VR's regardless of how often I drove, one short trip with a stuck cut out and you are out a lot more money than what you pay for the VR. KGB