What are these conenctors called?

[ppppenguin]

This general sort of connector, whether with or without the metal shell, has been used for HT batteries, loudspeakers and internally in Hacker radios. The ones in the photo have 2 pins but I've seen them with up to 5.

What are they called? Is there an old catalogue online that shows them?

[Mike Watterson]

I've only seen them named by function.
This is from a catalogue advertising radio batteries. Not named in catalogue.
http://www.blaukatz.com/tables/layer-ht-...batteries/

I'm familiar with them from about 1965. Often without the shell.

Like an ancient version of the DIN connector in usage. The USA specific battery connectors  are usually  larger. The most pins I've  seen was for PSU to radio head on an Ekco valve car radio (maybe 5). However the Zenith Transoceanic with scale lamp does use the UK size common 1.5V plug, but on battery I've never seen anything else use. A regular C cell fits in a replica. 
Various spacings of 2 pin with one pin larger than  the  other:

• 1.5V LT
  
• 7.5V LT
  
• VHF radio aerial
  
• Mains selector (with an underside short)
  
• External speaker
  

The common 45V and 90V three pin have a different offset on the middle.

Four pin sometimes for record player cartridge inside a cabinet.

The sockets are harder to get than plugs, so I usually make them.

I've various NOS two pin ones that don't fit the usual 1.5V LT packs.

[Mike Watterson]

And the 1939 and later combo 1.5V + 90V four pin large HT plug used on many battery models is the B4 valve plug/base. The LT pins correspond and HT- was often the B4 cathode or grid, HT+ was sometimes the anode.

[Andy M0FYA]

The two-pin one, I suspect the type shown in the photo, was certainly in use during WW2 in some of the equipment I am interested in, parts of H2S radar!
They were used internally to connect 24v to the blower motor (more correctly, to the suppressor unit which then fed the blower motor) used in the main display unit to cool the L.O. klystron, and in the transmitter to cool the magnetron. 
I have previously searched the documentation to find a part number or other reference, to no avail.
The socket on the suppressor unit has a retaining ring with spring fingers to grip the plug body and prevent it inadvertently detaching.

Andy

[Mike Watterson]

I do think they might have originated in 1938 or 1939 as power connectors to replace wander plugs on HT packs, particularly 45V and 90V. Maybe even some USA 1.5V LT packs in 1938 when the Sylvania 1.4V filament octal tubes were released. But I've never even seen a part number for the sockets or plugs.