Looking on eBay today, I came across some listing for vintage
3 way “Hospital bulbs”. They are mogul base, but unlike the 100-200-300 wattage ones I’m familiar with in Torchiere lamps, these are 150-250-400 watts.

I’m assuming maybe these were used for lights in ORs? I haven’t seen any mogul sockets for these either, the ones I’ve seen in most mogul 3 way lamps are rated at 300 W maximum.

I did a quick search on here but didn’t notice anything about these bulbs.

OR lamps are one of the few applications where 3-Way lamps were also widely used in Europe.  Usually one of the filaments was rated 12V or 24V, intended for battery operation in case of a mains power failure.

Interesting! The Hospital bulbs here in the US I’m seeing are 120V AC only.

So I take it 3 way bulbs are mainly an American thing?

I’ve heard the mogul based 3 way 100-200-300 were not something that exists in the UK.

OR lamps are one of the few applications where 3-Way lamps were also widely used in Europe.  Usually one of the filaments was rated 12V or 24V, intended for battery operation in case of a mains power failure.

hello

I have one of these bulbs made by Narva, however the base is slightly different to the normal three mogul base E39d). Apart from being 40mm long the center contact is not flush bot extruded. Im not sure of that sockets designation however maybe EF40-d?

Best regards,

Alex

3-way lamps are/were very rare in the UK. Philips tried to introduce them in the 60's and early 70's but they never really took off, more's the pity, I rather liked them 

Indeed Alex, I have a couple of Philips Hospital double filament lamps for 230V / 24V supply and those also have the protruding pin cap.  I believe that was intended to allow the lamp to be screwed slightly in or out of its lampholder, adjusting the filament height in the reflector to optimise beam focussing.

 @ Cole D : I have one : https://www.lighting-gallery.net/gallery/displayimage.php?album=5206&pos=11&pid=225286

Nice!