PE-214 rectifier fix

[Laminatrap]

Please let me know if I have this listed in the wrong forum.

Back story:

I have been looking for a PE-210 6-22 DC volt generator for a few years without any luck. I have been looking for this to go with a battery charging rack that I believe was inclusive to the batteries for the infrared scopes.

In place of a PE-210, I picked up a PE214 to display with the rack. At 110 AC volts it could technically power the battery rack, but was not the the correct one as pictured in the manuals.

Last fall, After receiving this wonderful little WW2 PE-214 I went over it before attempting to start it up. Incredibly it started right up. It did however seem to running a bit fast. Putting a meter on it confirmed it was over charging/over revving.
Hitting the manual it seems the problem was with the selenium rectifier not doing its job after all of these years. The selenium rectifier converts the AC to DC for the electric governor. I tried some fixes that I found in various places without any luck. I also had no luck sourcing a suitable replacement selenium rectifier.

I did try a modern diode rectifier, but the selenium rectifier has an inherent voltage drop due to the nature of the rectifier. The result was a higher voltage to the electronic governor giving the wrong output voltages of the generator.
I reached out to some mentors on an old radio forum for solution. One f them was kind enough to send me a large potentiometer to put in line and find the required resistance to bring it to the required voltage. From there I picked up an appropriate resistor and it worked quite well.

The next problem was hiding the modern electronics. I then decided to hide it in plain sight. I turned a piece of aluminum, which doubled as a heat sink. Anodized it a dull black/gray.

not prefect, but once the shield was put on I would think most would not even notice.

At this point the wires were not routed as I was planning on ordering some black cloth wrapped wire to replace the yellow.

From memory the rectifier uses was a standard full wave rectifier bridge. A 8 ohm 1/2 watt ceramic resistor was on the positive output to ground which went to one leg of the governor.

This may have been due to the generator actually being a positive ground unit?

Doing spring cleaning I came across the unit again and realized I have not posted here in case anyone else has the same issue.
Contemplating turning another piece with the smaller diameter as well as thinner fins.
A appropriate potentiometer could be attached to the heat sing with some crafty bracket that would replace one side of the mounting threaded bar. This would afford the user fine tuning as needed.
Just the same I think I am done tinkering with unit and continuing my search for a PE-210. If anyone knows of a WW2 or even a Korean era PE-210 for sale please keep me in mind.

Any questions or comments, do not hesitate to let me know

[jesse]

My governor was mechanically stuck and was running too fast. Once i freed it up it ran fine.

[Laminatrap]

Jesse, Great to hear!
What was stuck on it? Basically an electro-magnet with the throttle linkage on a floating plunger that moves from the field.

Is it regulating the output voltage correctly?

[N6CC]

Nice job with the repair! I have a PU-181 with the same engine/voltage regulator. The selenium rectifier failed after 69 years so I needed a functional replacement using silicon diodes and a dropping resistor. I went for functionality versus the "original look" this time but it works well. Details at the bottom of this post on my website: https://www.n6cc.com/gensets-for-an-grc-109-etc/
Running this genny with mil radios at military vehicle shows is always a hit! Cheers, Tim