[Racal] Racal (and others): peculiar mains power connector question

[Bart Wessel]

Hi all,

(Hope this makes sense to you, I am writing in a language foreign to my own.)

I am confused. Let me explain.

I own several boatanchors originating from the UK that have a three-pin 
power connector, like the one on the Racal 17. Err, well - I ASSUME every 
Racal 17 has this particular connector, so
I am already at unfamiliar territory here....

The gear I am referring to: a Racal 17, a Racal sideband convertor, a 
Marconi signal generator and a Cossor scope. Maybe this is of some relevance.

The power connector I am talking about has three pins labeled A, B and C - 
the first two of which are connected to the mains and the latter is 
connected to earth. All four boatanchors use the same pin dedication - no 
problem here.

This pecular connector has notches on the outer ring, enabling it to be 
connected in only one way to the socket. But the innards of the connector 
can be rotated during assembly, allowing for several different 
orientations. The socket on the chassis is made up the same way.

I would assume that there is one standard way to orientate the innards of 
such a plug in the outer ring. Then any powercord would plug into any 
equipment - easy.
Apparently there isn't just one standard, as the connector for the Marconi 
and the Cossor are interchangable, but fit neither the Racal 17 nor the 
Racal sideband convertor. And the plug on the Racal 17 isn't identical to 
the one on the sideband convertor either!

So I end up with four pieces of equipment and three different plug 
orientations.

So.... What is the story about this type of mains plug? Are they supposed 
to be different?
Anybody any ideas?

Just curious, I can plug them in allright, but the question keeps nagging 
at me ;-)


Best,

                 Bart, de PA3GYU.