[GreenKeys] RA87 and BE-77-A connection update

[Steve Schlink]

Gary,

AFAIK, (and I stand to be corrected) the twisting lock connectors (generic) 
were proprietary back in those days, so one manufacturer's plug wouldn't 
fit a competitor's  cap (female cord end). Later, when NEMA came along, 
these were standardized and everything was interchangeable by NEMA Lxx 
nomenclature.

I would suggest that you look closely at the receptacle for a 
manufacturer's name or trade name. My guess is that it is NOT a Hubbell 
Twist Lok (TM, no "C"), but that of a competitor. Arrow-Hart made similar 
devices, called Turn & Pull.

And to make matters worse, I don't think that NEMA ever standardized a 2 
wire plug/cap, as by then grounding was required.

WECo used a similar jack on their early 551A KSU.

It would probably by advantageous to post a photo of and the diameter 
dimension of the contacts, so that everyone knows what/which we are looking 
for.

What was the part number of the Hubbell caps that you bought?

I need to dig around in my several junk boxes, but it's currently cold in 
the garage and I have a car down that I'm finishing re-installing the 
engine so ...

Steve

At 02:43 PM 12/20/2012 -0600, Gary Schulz wrote:
>Many thanks for all the replies to my questions regarding the connection 
>of the RA87 and the BE-77-A.  The 3 prong connector on the end of the 
>cable of the BE-77-A is absolutely original because this line unit was 
>just opened up by me fresh from the factory where it was wrapped up since 
>1943.  It was in a sealed taped up oiled paper wrapping and box with all 
>that old-fashioned fiber packing material.  The unit is untouched and 
>unmodified so that's the way they made it.  That said, the manuals that 
>came with it show photographs with a standard rubber molded 2 prong AC 
>plug on the end.  The remaining mystery is that neither of these plugs is 
>what is on the RA-87 even though it was supposed to be connected directly 
>to it!
>
>One of you gave me a pointer to a Hubbel 2-prong twist-lock plug carried 
>by Amazon.  I went and purchased 2 of those plugs and I am sorry to say 
>they are not really compatible.  They are similar and can be made to push 
>into the receptacle on the RA87 but the blade spacing on the RA87 is 
>slightly wider than the blades on those plugs.  The blades wind up 
>splaying out and definitely will not twist once inserted.
>
>Even so it would appear that once they are inserted, they do make some 
>electrical contact so may work enough to get me going.
>
>I ripped apart the capacitors inside the RA87 and I have inserted new guts 
>and have reassembled the cans.  Hopefully over the holiday I can see if I 
>can hear the musical notes coming from my refurbished M15 printer!
>
>Gary Schulz
>WB9YIR
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