USAAF X-Ray Warning Light

[dave walsh]

Yes I can see you are after both technical simplicity AND originality Richard. If you were on Salvage Hunters [Quest] they would just whip out the socket for a [possibly] hard to source bulb and stick in an LED device.

How much of that is actually restoration? It's a common issue on here, just like how long is a piece of string

Dave W

[YoungManGW]

A couple of photos attached. In the first, the three pin (male) socket is to the right, the two pin (female) socket to the rear left. Note also the unusual lamp holder, which clips into place by way of a side 'tongue'. There should be another one at the top - missing. The second photo shows the transformer's part numbers, etc. The third photo shows the connections up to the rotating lamp. Hope these are useful.

Regards,
Richard

[YoungManGW]

Photo 2.

[YoungManGW]

Photo 3.

[emeritus]

On reflection, when testing using a resistive dropper, it would not be necessary to ensure that the dropper had to such as to yield an input voltage of exactly 115V. It would be sufficient to connect in series with a lamp load, measure the voltage across its mains input, measure the voltage across the internal lamp's terminals, and divide one by the other to determine the transformer ratio.

[Andrewausfa]

Has the transformer got an NSN number on it that we can't see? It should begin with 5950

64F21148- is a mil code for Electric Interior Illuminated Sign. The other option would be to see if you can cross reference Freeds 40250 part number.
Andrew

[Al (astral highway)]

Originally Posted by GrimJosef

"Unfortunately there are no bulbs".

Ahah, yes. I was out and about and still thinking about it, so posted it on the hoof-- as I often seem to do!

Easy to forget earlier posts, at least, that's what I find if I get distracted in this way!

[Chris_A]

Is there any rectification of the supply to the Beacon, it looks like a variant of a Grimes anti-collision beacon, these would normally be 24-28vdc although I know that there were other input variants. Are there any markings on the beacon I may be able to look it up if there are.

Chris

[paulsherwin]

It appears to be a fairly low current device. Couldn't you just use one of those autotransformers designed to allow American tourists to use their appliances in 230V countries? 200W or even 100W should be fine.

[TonyDuell]

Originally Posted by Chris_A

Is there any rectification of the supply to the Beacon, it looks like a variant of a Grimes anti-collision beacon, these would normally be 24-28vdc although I know that there were other input variants. Are there any markings on the beacon I may be able to look it up if there are.

In 'photo 3' there is something with 'Lytic' printed on it. I assume this is an electrolytic capacitor, which implies there is a DC supply around, probably produced by rectifying the output of that transformer.

[dave walsh]

Re your post 29* and the ones at 17*/20*/21* .....apparently not Paul! I also thought that it must be a low current device when automotive bulbs were suggested [as opposed to my Dock Light]. It's not new problem. A lot of collectors are completists at heart but deciding when that's appropriate or it's even worth it, is an individual decision to make.... I suppose!

Dave W

[YoungManGW]

Will acquire a cheapy 240v to 115v transformer, rig that, and report back. Many thanks for all the advice so far.

Regards,
Richard

[YoungManGW]

Righto, I can get a 230v to 110v 45w plug-in transformer for about £10. The outlet from that is a socket for a US two pin/blade plug. I'll need two of those, one for that end, and one for the other, to connect to the lamp. However, wireable two pin/blade US plugs seem to be like hen's teeth in Blighty. Does anyone have a couple perchance please? I will of course meet costs. Many thanks.

Regards,
Richard

[McMurdo]

if your converter is an autotransformer then I'd make sure the earth is made right through to the lamp. Most of these things only have a 2-pin outlet for double insulated appliances

[Al (astral highway)]

Hey Richard ,

Maybe someone on the forum can offer you a spare 240:24v transformer ( or any low voltage secondary ). Then you have your voltage source and you can find the turns ratio by measuring the secondary voltage. Little expense and a reliable test! Ask in parts and service information wanted.

Then you can do what Terry in post no 8 suggests. Then no frustrating hunting around for bespoke rare connectors !!

By the way, can you describe the appearance of the secondary winding compared to the primary ? Thickness of wire, space taken up in comparison with secondary ?

Another thing you can do is wire up a 24v automotive bulb and see if it glows dimly or brightly or blows. It’s a fuse if the voltage it too high , so no harm done. It could also be the correct voltage !!

[dseymo1]

Perhaps I'm missing something, but if the lamp is missing, and you intend replacing the transformer, surely all that matters is the motor voltage, which will almost certainly be on a rating plate somewhere? Assuming that you can feed the motor accordingly (capacitor dropper?), a replacement transformer only has to match a lamp of your choosing,irrespective of the original lamp voltage.

[Refugee]

Looking at the photos gives me the impression that the lamp in the base is a "mains" lamp and that the transformer powers a vehicle type beacon.
I would dab the motor wires onto a 9 volt battery and see how fast the motor goes.
If it goes anything like fast enough it will almost certainly be 12 volts.

[YoungManGW]

Unfortunately, there is no rating plate to identify the voltage demanded by the motor.

To clarify re. lamps:
- there would have been two in the body of the sign, one at the bottom, and one at the top
- neither lamp is in place, and only one of the (very unusual) lamp holders is extant
- there would have been two lamps in the rotating assembly, possibly 24v
- neither of these is in place

It's quite right to say though that only the voltage demanded by the motor and the lamps in the rotating assembly need to be determined. Replacement lamps in the body could be directly fed the right voltage.

What I'm trying to do, for originality purposes, though is:
- avoid drilling a hole (for new wiring) in the sides or base of the body
- thus, retain the original US 3-pin Hubbell connector socket, and the original US 2-pin connector socket
- connect the supply via one or other of these

Looks like that can be done one of two ways:
- wall wart transformer, connected via one of the two original sockets (I've noted the advice to use the 3-pin one so as to provide an earth)
- standard UK plug connected to one of the two original sockets, with a second transformer inside the body.

In essence, there are two difficulties to overcome:
- determination of the output voltage of the original transformer
- connection between UK mains and the original US sockets.

I'm really keen to avoid visible changes.

Many thanks.

Regards,
Richard

[YoungManGW]

Thanks Refugee, will give that a whirl, as it were.

Regards,
Richard

[Chris_A]

Richard,
I've attached a couple of pictures of a Grimes Anti-Collision Beacon, I'm reasonably sure that's whats fitted.
They seem to have been available in 12vdc, 24vdc or 115v 400Hz as there's no sign of frequency conversion assume it's 12 or 24 volt.
Once you find out which you have there is an old catalog on the net which will give you part numbers for replacement lamps, I could PM you a copy if you can't find it
Chris