Wireless Set No. 52 Canadian - Project

[David Dunlop]

I decided to have a closer look at the two Robbins & Myers Rotary Transformers in the Supply Unit today. Not that I can do anything much with them at the moment, but more to get a better understanding of how they were assembled. A challenging task at the best of times made even more so with no surviving documentation explaining the process in detail, no detailed identification of parts and no currently known source of replacement parts.

It was the lower Rotary Transformer HP, MG2A, I decided to look at today without actually trying to remove it from the Supply Unit chassis. Since repacking the armature end bearings is one of the tasks down the road, I started by removing the end cap that was readily accessible at the back of the Supply Unit; the left end one on the transformer itself when looking at its data plate.

The end cap is a simple flat plate secured with four countersunk, slot head screws. These screws turned out to be 6-32 machine screws, in two different lengths; two of each. The shorter pair were 7/16 inch and the longer ones 9/16 inch and I carefully noted where they all came from because I have no idea at all at the moment if sizes are deliberate, or not, so best return them from where they came.

My initial impression is the end cap and the screws are all brass, but I will confirm that eventually with a magnet. With the end cap off, the next part to show up was the paper gasket keeping the Andoc-C grease in place. I did not attempt to remove it this time around in case I managed to damage it. It sure was tempting, however.

I noticed the gasket is a perfect match to the end cap in diameter and the location of the four punched screw holes. It may be the factory original gasket, or probably a factory made replacement installed in 1966. I have now added to my notes to look into whether or not this type of grease gasket paper is still available and get some in stock before exploring any further.


David