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Old 12-01-23, 23:15
David Dunlop David Dunlop is offline
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Default Canadian Marconi Company Capacitors

Does anyone know if CMC produced their own capacitors during World War Two, or during the interwar years? Sprague, Aerovox, Solar and Mallory were very active in this sector as were a number of other major electronic equipment manufacturers.

Canadian Marconi Company may not have been producing capacitors on a large, wholesale basis, but I wonder if they had the ability to make special spec capacitors themselves, if needed.


David
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Old 14-01-23, 21:49
Bruce MacMillan Bruce MacMillan is offline
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Default

Some in the military sets could be made in Canada as Canadian Marconi had aquired Hunt Capacitor (Canada) Ltd. CMC was large enough to do that production in house. The big one in the dc power supply was US made.
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Old 15-01-23, 17:06
David Dunlop David Dunlop is offline
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Default Capacitor CMC 111-225

Firstly today, thank you Bruce for the information on the Hunt Capacitor (Canada) Company, and the acquisition of them by Canadian Marconi Company. Both items are new to me.

I have now found a pair of Canadian Marconi Company capacitors still in place in the Sender, photo attached. I have not yet exactly identified which circuit component each of these capacitors are, but the only available options are, C19C and C19D. C19C will be the V1J Grid A.F. Bypass capacitor and C19D will be the Keying Spark Suppression capacitor. And both have now been added to my list of capacitors to test. Sigh.

The first thing that jumps out at you with these capacitors is the printing. Unlike the Sprague and Aerovox capacitors of similar design, these CMC items are printed around the circumference of the cardboard sleeve, not parallel to the long axis. When you look this capacitor up in the Illustrated Parts List for the 52-Set, the specs are:



CAPACITORS, Electrolytic, 100-uF, 15-V, -10% + 75% with metal cleat 1/4-inch wide, extending 23/32-inch, has a mtg hole 3/16-inch from end. ZA/CAN 4450, CMC 111-225

* The manual indicates ‘No Substitution’ for this capacitor.

The way the printing is arranged, there is a gap in the middle of the capacitor where the cleat sits. Below it I can see ‘MADE IN CANADA’ and possible two other lines. The last appears to say ‘NEGATIVE’.

A quick look around the rest of the Sender shows no other surviving Canadian Marconi capacitors. The next time I am poking about the two receivers I will take a look in them to see it any turn up there.


David
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  #4  
Old 16-01-23, 22:52
David Dunlop David Dunlop is offline
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Default Capacitor CMC 111-267

I went through the parted out Receiver components this morning and only found two Canadian Marconi Company made capacitors. Both were on the Receiver Tag Panel KR and both were CMC 111-267. These are CAPACITORS, Oil-Paper, .01-uF, 600 Volt 20%, ZA/CAN 4471, but are the small, 1/2-inch diameter ones, so the printing on them all follows the longitudinal axis of the capacitor. They are the top and bottom ones in the photo attached. All other paper sleeved capacitors in that receiver were the paper wrapped Aerovox ones, as per the other two in the photo. These two CMC capacitors are C20A V1G Grid Audio Coupling and C20B V1H Grid Audio Coupling.

When I next get around to poking about in the other two receivers, the Supply Unit and the Remote Supply Unit, I will see if any more CMC capacitors turn up.


David
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CMC Capacitors 2.JPG  
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