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Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details. |
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11th Dec 2010, 6:36 pm | #61 |
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Re: Vintage Christmas Tree lights
Hello Dave,
I'd wondered about feeding each string with a constant-current supply - remove the fuse bulb of course. Certainly, given the shortage of spares and the proliferation of incompatible fittings that might yet be worthwhile. An AC constant-current would be fairly straightforward with a full-wave rectifier and an appropriately-wired voltage regulator. Regards Ant |
12th Dec 2010, 9:08 pm | #62 |
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Re: Vintage Christmas Tree lights
@ davegsm82: That's sort of how the modern ones work anyway. There is a voltage-dependent device across the filament of each bulb except the fuse bulb. It is normally open circuit. If the bulb fails, the full strength of the mains appears across the device and it begins to conduct.
Some of the first electric street lights were wired in series. In parallel with each bulb was a pair of contacts separated by a thin layer of paper impregnated with some inflammable chemical. If a bulb failed, the high voltage appearing across the paper ignited it, allowing the contacts to touch and re-complete the circuit when it burned right through.
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13th Dec 2010, 10:51 am | #63 |
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Re: Vintage Christmas Tree lights
Hello all,
I dismantled a coloured bulb; there's a loop of wire round the bottoms of the filament supports such that when the filament goes the suports spring out slightly and the loop shorts them together. I tried to blow it and couldn't with the PSU easily to hand last night - how come these darned things aren't so robust when they're in service...? Regrads Ant |
13th Dec 2010, 1:46 pm | #64 |
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Re: Vintage Christmas Tree lights
We had a set of outside lights a few years ago which had bulbs with the shorting feature. There were 40 of them in 4 strings of 10 bulbs each. The odd one failed but was easily replaced then about 4 years ago they all started going. As each one failed the same 30v was across fewer and fewer bulbs until only one bulb was left working. We now have a new set of LED lights which hopefully will be more reliable.
Keith |
13th Dec 2010, 4:33 pm | #65 |
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Re: Vintage Christmas Tree lights
This would seem to be the "achilles heel" of shorting features. If the dead bulb is not replaced before any more go, the strain is going to increase each time a bulb blows - presumably reaching a point when bulbs will blow in rapid succession - followed by whatever fuse is supplied.
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13th Dec 2010, 4:43 pm | #66 |
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Re: Vintage Christmas Tree lights
That's why there's supposed to be a fuse bulb (the one with the white-painted tip) in each string, which doesn't have the shorting feature. The ones I remember from 20-light sets were rated at 12V 1W as opposed to 12V 1.1W for the other bulbs, and so slightly overrun, so should fail in preference to all the other bulbs. I don't think it always worked out that way, though, especially if all the bulbs were different ages!
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13th Dec 2010, 5:22 pm | #67 |
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Re: Vintage Christmas Tree lights
The lights were intended for ouside use and ran from a 30v transformer. I presume the lack of fuse was intended to encourage you to buy new lights every few years. The bulbs appeared to have two layers of glass, one was the actual bulb probably around 1/4" diameter with a second coloured bulbous outer layer.
If you caught them in time you could spot the unlit one and replace it before the chain reaction set in. Keith |
13th Dec 2010, 6:27 pm | #68 |
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Re: Vintage Christmas Tree lights
Try putting a 'dud' bulb across a battery. It often lights, normally suggesting that the filament has gone low resistance. Weird. J.
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13th Dec 2010, 6:56 pm | #69 |
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Re: Vintage Christmas Tree lights
The fuse bulb is usually the one with the white paint on it and either the first or the last in a chain. (Normally first.) This does not have a short circuit facility and when it fails, the whole chain goes out. Then Mrs. C.Roads would replace it with a normal bulb...
If you examine the normal bulbs, the little blob under the filament is the short circuit device and it does not always work, but when it does that bulb goes out and the rest of the set goes a bit brighter. These were known outside the industry (round here anyway) as 'circuit keepers' rather than blown bulbs. Two or more and fuse bulb would fail. Tip - get a few more lights off an old chain and put them in series with the set. Dims them. as does a 60w bulb (remember them?) in series with the chain. Cheers, Steve P.
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13th Dec 2010, 10:08 pm | #70 |
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Re: Vintage Christmas Tree lights
having started this thread nearly 6 months ago
I thought you would like a photo I will put up photo of the real tree tomorrow Happy Christmas Everybody |
13th Dec 2010, 11:41 pm | #71 |
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Re: Vintage Christmas Tree lights
Love that second picture, reminds me of something from one of those public information films from the 70's
Jay
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14th Dec 2010, 12:17 am | #72 |
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Re: Vintage Christmas Tree lights
Peter I don't know why you need the pine tree, why not just plant the adaptor tree in a pot, let it grow a bit and decorate that instead. Splendid stuff!
Lucien |
14th Dec 2010, 12:21 am | #73 |
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Re: Vintage Christmas Tree lights
Agreed! Well said Lucien
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14th Dec 2010, 12:55 am | #74 |
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Re: Vintage Christmas Tree lights
i might have a go
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14th Dec 2010, 3:18 pm | #75 |
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Re: Vintage Christmas Tree lights
@ HKS: If the bulbs are using semiconductor rather than mechanical protective devices, it's possible that the filament could have gone a bit high resistance; allowing just enough of a voltage to develop to trip the device. It then recovers (it doesn't have to; it will still do its job if it fails short, as semiconductors are prone to do) when the power is disconnected. The battery doesn't have enough voltage to trip the protector, so the bulb lights.
Mechanical protective devices have their own failure modes.
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20th Dec 2010, 1:19 am | #76 |
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Re: Vintage Christmas Tree lights
Well I have finally got around to putting my vintage set of Christmas lights up. I remember buying these when I was 14 from the local Woolworths in Helston. They are a 12 set of miniture olive bulbs rated at 20v. I have kept them going by using a slider dimmong switch to eliminate that switch on surge from cold. It seems to have worked but I am now down to my final set of spare bulbs.
The final shot is of them slung across the inside of my workshop window. Its a very tricky operation to put them up as I try to avoid the bulbs touching the window and also making sure they are all visible from outside so that I can look up at them and count all 12 bulbs easily, so if any fail I can act quickly. I have to use the traditional candle arch to provide sufficient load for the dimmer switch, failure to do this results in a continually flickering display.
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Simon BVWS member Last edited by Hybrid tellies; 20th Dec 2010 at 1:28 am. |
20th Dec 2010, 8:48 pm | #77 |
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Re: Vintage Christmas Tree lights
That Winfield pack is historic in ittself!
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22nd Dec 2010, 8:55 pm | #78 |
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Re: Vintage Christmas Tree lights
Hi Simon,
I can remember my parents having a set like this and i think that these are fabulous. I wouldn't mind trying to lay my hands on some. Rob |
22nd Dec 2010, 9:53 pm | #79 |
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Re: Vintage Christmas Tree lights
Thanks. I am just about to switch them on for a few hours. I will try not to throw out that Winfield pack when I use the last 3 bulbs. Rob I can only suggest you keep an eye on Ebay.
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22nd Dec 2010, 10:00 pm | #80 |
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Re: Vintage Christmas Tree lights
Hi Simon,
Thanks, no intention that I was after yours - when this thread started it I made me think of some great family Christmas's that we had experienced as a family a long time ago. Yes, I am keeping my eyes peeled on ebay. Regards Rob |