Why don't they make relay cutouts?

[Sunny the Model A]

Before you go yapping on about alternators and diodes here me out. I have had nothing but endless grief with those alternatives. My s10 and 53 210 have gone through 5 alternators and I gave up on em. and my A had a bad reaction to diode cutouts. When I got my A it had the wires disconnected from the cutout, turns out it had a diode cutout. when I ran it with the generator charging on minimum, it only drove about 10 miles and burned out. Then I shelled out and got a nurex, same thing. this time it boiled the battery. I got an original cutout and it worked magically. They key is that it prevents the generator from putting out too much voltage, it turns off after 6.8v or so on my truck. I want to find a relay cutout supplier for when I'm rebuilding generator and eventually making new generators. I know diodes are common but in my opinion they suck. So is there anyone who makes the relay cutout or is there blueprints for the original? thanks in advance

[whirnot]

Berts sells rebuilt relay cutouts

[Bruce of MN]

Try Barner @ndnchf

[nkaminar]

The alternators that failed that Sunny talked about probably failed because the brushes wore out. Yes, alternators have brushes to supply electricity to the rotating part. When you brought your car in for repair because the alternator was not working, the repair shop would just replace the alternator, where in fact all that was needed was replacement of the brushes. But that required some intelligence and work and would not bring in the same amount of money.

Regarding cutouts: These also require some intelligence and cost more to make than just installing a diode. There are numerous stampings and coils to wind, out of expensive copper wire. The points are made out of tungsten and have to be brazed to their arms. And then they have to be adjusted.

[Sunny the Model A]

Originally Posted by nkaminar

The alternators that failed that Sunny talked about probably failed because the brushes wore out. Yes, alternators have brushes to supply electricity to the rotating part. When you brought your car in for repair because the alternator was not working, the repair shop would just replace the alternator, where in fact all that was needed was replacement of the brushes. But that required some intelligence and work and would not bring in the same amount of money than just replacing a $5 part.

Regarding cutouts: These also require some intelligence and cost more to make than just installing a diode. There are numerous stampings and coils to wind, out of expensive copper wire. The points are made out of tungsten and have to be brazed to their arms. And then they have to be adjusted.

when the alternators burned up on my chevys, 4 out of 5 had burned out the rectifier circuits, brushes were fine. I checked that myself. The fifth had seized up the rear bearing, since you can't oil it it ran dry and locked up. I have zero faith in the blasted things. As far as finding a new cutout, I have found a few originals to study. If I can't find new ones, I'll look into having the components reproduced.

[Sunny the Model A]

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Originally Posted by nkaminar

The alternators that failed that Sunny talked about probably failed because the brushes wore out. Yes, alternators have brushes to supply electricity to the rotating part. When you brought your car in for repair because the alternator was not working, the repair shop would just replace the alternator, where in fact all that was needed was replacement of the brushes. But that required some intelligence and work and would not bring in the same amount of money than just replacing a $5 part.

Regarding cutouts: These also require some intelligence and cost more to make than just installing a diode. There are numerous stampings and coils to wind, out of expensive copper wire. The points are made out of tungsten and have to be brazed to their arms. And then they have to be adjusted.

when the alternators burned up on my chevys, 4 out of 5 had burned out the rectifier circuits, brushes were fine. I checked that myself. The fifth had seized up the rear bearing, since you can't oil it it ran dry and locked up. I have zero faith in the blasted things. As far as finding a new cutout, I have found a few originals to study. If I can't find new ones, I'll look into having the components reproduced. One day the originals will dry up and new ones will have to be produced, and the diodes boil out the batteries and alternators burn up the wiring. I have had to replace the wiring in alternator a's several times and my 53 has almost caught fire from overcharging. So eventually I foresee a desire a return to the old reliable relays and generators. With the manufacturing capabilities of today, a reproduction relay cutout is very feasable.

[katy]

Originally Posted by Sunny the Model A

when the alternators burned up on my chevys, 4 out of 5 had burned out the rectifier circuits, brushes were fine.

That tells me that the rectifiers were sub-par quality, and/or the voltage regulators were faulty.

[rotorwrench]

Alternators use a similar set of power diodes in there bridge to that used by the model A diode cans. There have been bad batches of diodes from all of the manufacturers in the past. The condition of the battery and electrical system can also have an affect on how well electronic components last in service. The model A generators, with it's three brush designs, were not real high output units. The early powerhouse generator put out the most at a little over 20 amps. All of them are very sensitive to condition of the battery and system components. A bad battery can kill both alternators and generators even with functional voltage regulation. A bad ground path can also cause problems. It all has to be well maintained to make it last.

Nobody really knows how well a particular manufacturer's solid state components will work until they use them for a while. John Regan had pretty good luck with his fun projects regulators but Texas Instruments stopped production of the obsolete chip that he used so that killed the product after Bird Haven took it over.

A person could purchase a modern 6-volt three pole voltage regulator and remove the cut out pole for transplant into an old can but those model VR's aren't made as well as they were back when those units were common. The Ford tractor parts suppliers have cut outs for the N series tractors but I've not used any. Most are converted to alternators like the GM 10si now days. Not too many companies want to make a product that doesn't sell like hotcakes. It's just the way of business and always has been.

[Woodie1]

I have had good luck taking an old cutout & installing a diode from one of the Model A parts houses. My old original cutouts always seemed to help fry a generator. Maybe I was trying to set the charge rate too high back then. I had a diode conversion go bad last summer that I think had been in use for about 8 years.

[bobbader]

Can't comment on your Chevies, but if you had all those issues with the Model A, it might not be the components you're buying but something else in your electrical system that is causing them to "burn out". Electronic stuff can be great, but in an "un-fused" system, if there is something amiss elsewhere in the system, my experience is that an electronic component will "take the hit" when something shorts out. In the case of your Nu-Rex cutout, or the one that came on the car, it could be bad wiring in the generator or elsewhere. I had a customer "burn out" a brand new alternator because of shorted turn signal wiring.

"And the hip bone's connected to the thigh bone" ........ etc, etc, etc

[ndnchf]

Why don't they make relay cutouts? The simple answer is cost, supply and demand. The original Ford cutouts are very high quality and quite durable. Diode cutouts, when built with a proper heat dissapating system can be good too. But are not as tolerant of poor grounding or other external electrical problems.

I refurbish and use a lot of original Ford cutouts and know them pretty well. The most common problem I find is failure of the shunt winding. In some cases the points are badly eroded, but this is not common. The often repeated malady of "points stuck together" is very rare, not near as common as some people would have you believe.

There are aftermarket relay cutouts available. But they are poorly made. I would not use them. FWIW, in.my opinion. the best original Ford cutouts are those made after April 1936 with the "B" stamp, and Ford service replacements marked "BATT" and "ARM" which became available in 1942.
For anyone interested, I have a video on servicing original cutouts. See below.
Steve

https://youtu.be/rnuukBeJ6Zs?si=IaTf5_MM5Z94ii6d

[Sunny the Model A]

Originally Posted by bobbader

Can't comment on your Chevies, but if you had all those issues with the Model A, it might not be the components you're buying but something else in your electrical system that is causing them to "burn out". Electronic stuff can be great, but in an "un-fused" system, if there is something amiss elsewhere in the system, my experience is that an electronic component will "take the hit" when something shorts out. In the case of your Nu-Rex cutout, or the one that came on the car, it could be bad wiring in the generator or elsewhere. I had a customer "burn out" a brand new alternator because of shorted turn signal wiring.

"And the hip bone's connected to the thigh bone" ........ etc, etc, etc

All the alternator failings were on the chevys, the A has a fuse and blew out 2 diodes. I rated the fuse for 20 amps, enough to run the headlights at full brightness, once I switched back to the relay all my problems ceased in the charging department

[alexiskai]

Originally Posted by ndnchf

in.my opinion. the best original Ford cutouts are those made after April 1936 with the "B" stamp, and Ford service replacements marked "BAT" and "ARM" which became available in 1942.

Steve, do you have any photos of those later cutouts that folks could use as a visual reference?

[ndnchf]

Originally Posted by alexiskai

Steve, do you have any photos of those later cutouts that folks could use as a visual reference?

Sure. Also note the difference from the bottom. There are cheap cutouts marked Batt and Arm too, but their bases look very different.

BTW, in April 1936 they started using heavier copper windings, I assume in anticipation of higher output generators. For model A use, the older and newer cutouts all work fine.

Steve

[Fullraceflathead]

Thanks that's great info!!!