CTC models

[kx250rider]

There were also a few weird CTCs that were limited-runs designed for 32VDC operation. I worked on a couple of them. One was, if I recall, a CTC-14. Looked like a 12. It basically was a conventional chassis but had a 32VDC-117AC dynamotor. Zenith did that as late as the 80s, with a 32VDC version of the System III. It was identical except for the 9-160-05/06 board being a 9-160-FRM. That one was actually a different board altogether.

Charles

[Kevin Kuehn]

Were those 32vdc sets used on aircraft, or very remote rural areas?

[kx250rider]

Originally Posted by Kevin Kuehn

Were those 32vdc sets used on aircraft, or very remote rural areas?

Farm power (windmills, I believe). There are/were still a handful of 32VDC towns in very rural areas, at least as late as the 2000s as I've been told. Commercial planes, as far as I know are on 400 cycle AC (smaller military planes may be on 28vdc).

Charles

[Kevin Kuehn]

Thanks for clearing that up.

I thought possibly they were the Amish closet sets I've heard about

[Findm-Keepm]

Originally Posted by kx250rider

There were also a few weird CTCs that were limited-runs designed for 32VDC operation. I worked on a couple of them. One was, if I recall, a CTC-14. Looked like a 12. It basically was a conventional chassis but had a 32VDC-117AC dynamotor. Zenith did that as late as the 80s, with a 32VDC version of the System III. It was identical except for the 9-160-05/06 board being a 9-160-FRM. That one was actually a different board altogether.

Charles

...and Setchell Carlson made an 19" B/W inverter-based TV (more like a video monitor) for aircraft use. Conrac was left holding the bag on it when S-C went under. 27.5VDC input, and two 75-ohm impedance UHF connectors for input. I've seen one, used in the "Admiral's Bird", a Convair twin-prop post-WWII bird they had at NAS Norfolk Operations. The one I saw was a ready spare, but I don't think the original ever got pulled from the aircraft.

Cheers,

[David Roper]

Yeah, that's really bizarre when you go back in time and look at when farm lighting plants apparently peaked. The 1923 Sears catalog offered almost all appliances in 32 volt and 110 volt versions, but already by 1927 the catalog reflects a serious trend toward phasing out 32 volt items.

32 volt farm radios continued to be made through the 1930s and there were even a very few offered in the immediate postwar period. I have never seen a single schematic for a 32 volt DC TV set. If there wasn't enough demand in the 50s, well, by the 80s demand would have been effectively (if not literally) zero.

Up into the decade just passed you could still get 32 volt light bulbs, but apparently the only real demand was a marine application and the price per bulb was outrageous. To my knowledge they are no longer offered anywhere at any price.

[miniman82]

Military aircraft run 115 VAC, 3 phase 400 Hz and 28v redundant busses.

[ctc17]

yep 32 volts was rural farm wind power. I have an instruction sheet that explains how to change the standard 5 tube radio to kinda work on 32 volts dc.
A 32 volt dynamotor powered color tv....what a current hog that would be!

[kx250rider]

Originally Posted by ctc17

yep 32 volts was rural farm wind power. I have an instruction sheet that explains how to change the standard 5 tube radio to kinda work on 32 volts dc.
A 32 volt dynamotor powered color tv....what a current hog that would be!

And a TV collector who wants a big color set from the 50s with a dynamotor power converter, should be a competitive class weightlifter

Charles

[bgadow]

I've often thought about that 32vdc Zenith that Charles mentions. Neat to think about a place so desolate that the power lines hadn't made it there yet. I have seen some towns on a map that could fit that description.

I'll have to ask around at the steam and gas shows this summer. There are some guys with a lot of old (small) power plants in running order, mostly Kohlers (which are pretty cool, I think). How big were the 32v Delco units, and what engine typically powered them?

[Electronic M]

This therad is really interesting! I used to think there were not any CTC-13 or 14 chassis even designed, and also thought that 32VDC areas dissapeared in the 50's. Wow the cool things one can learn on these forums!

Tom C.

[kx250rider]

Originally Posted by Electronic M

thought that 32VDC areas dissapeared in the 50's. Wow the cool things one can learn on these forums!

Tom C.

Most did, but there are still holdouts where farmers are so remote that they don't want to pay utility bonds to string power lines miles & miles. I would assume that by now in 2011, they would have solar power and/or Diesel generators. But if they still have operational 32v sources and pumps/machinery, it would make good sense I guess, to keep it as long as it's maintainable.

Charles

[bgadow]

JBL, I find that sort of thing very interesting. I'm sure many of us would enjoy the stories if you wanted to share more.

[Geoff Bourquin]

A CTC 211? What new things did it offer?