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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 17th Sep 2018, 6:37 pm   #21
ColinTheAmpMan1
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Default Re: What's this? A quiz.

Quote:
Originally Posted by Kentode View Post
Now I've got to research "the wigwam that winds the sun up"!

An advertising slogan?
This was a phrase used by the father of a school-friend many years ago. He was an engineer and used it for anything that he couldn't recognise the purpose of. Does that solve it?
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Old 17th Sep 2018, 6:47 pm   #22
kalee20
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Default Re: What's this? A quiz.

Quote:
Originally Posted by Restoration73 View Post
Many of the early GB (Gaumont British, later Rank) Equipments 16mm film projectors
used a 120v lamp, and an external dropper was required. I think the early projectors
were actually Bell & Howell made in the USA.
It's appallingly inefficient, but it does mean the lamp has good protection against switch-on surges, so life can be quite long, almost to the point where light output is falling because of blackening inside the bulb before the filament breaks.
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Old 17th Sep 2018, 6:57 pm   #23
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Default Re: What's this? A quiz.

I had one as a kid!
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Old 17th Sep 2018, 7:44 pm   #24
Kentode
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Default Re: What's this? A quiz.

One what Sam? The dropper? What did you use it for?

The "whim-wham" was a parents answer to the annoying child's questions! As in "Go and play with the traffic", one of my father's favourite ways of letting me know he was busy.
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Old 17th Sep 2018, 7:44 pm   #25
Lucien Nunes
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Default Re: What's this? A quiz.

Many home projectors, especially 8 & 9.5mm, had resistive voltage droppers. A lower voltage lamp has a shorter, thicker filament which in the lower power ranges e.g. 50W has a real impact on life and luminous efficacy as it can be run hotter / brighter/ whiter and focus better, yet still last longer than a 240V lamp. The power lost in the resistance was only a minor nuisance in the grand scheme of things. Most of these were showing films of tens or low hundreds of feet at a time, so not on for all that long. Some did have transformers for the lamp, but as the motors were often universal, the transformer restricted an inherently AC/DC machine to AC only.

Before the advent of halogen projection lamps, professional / commercial 16mm projectors for AC only often used 115V lamps run from an external transformer. In fact the whole projector was often 115V including motor and amplifier. For DC service where the mains was not 115V, a 230V lamp did away with the need for a huge resistance but at the expense of fragility. Many later substandard projectors for AC only used 12/24V lamps up to 250W run from a transformer, or a secondary on the induction motor winding.
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Old 17th Sep 2018, 7:50 pm   #26
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Default Re: What's this? A quiz.

Thanks for the information Lucien, so it might be good for 50 Watts, that's handy.

I'll post the outcome of my experience with it, especially the heat dissipation.
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Old 17th Sep 2018, 9:36 pm   #27
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Default Re: What's this? A quiz.

I am not going to start googling, but i think the Wim-wam was a bit like perpetual motion and transmutation, a genuine belief of earlier times.
That was the impression I got from parental questioning. There really were less enlightened times (in a scientific sense, maybe not in other senses).
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Old 18th Sep 2018, 8:43 pm   #28
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Default Re: What's this? A quiz.

I've got a 16mm Eumig projector from the 1950's, which while currently fitted with a 250V lamp originally could be fitted with an 120V lamp, requiring an external voltage dropper of a similar type (I've never seen the dropper in real life, only pictures). The socket for the dropper is still there, but there's a short circuit plug for it (which must be unplugged if for whatever reason one wants to run the projector without the lamp turning on).
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Old 19th Sep 2018, 7:16 am   #29
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Default Re: What's this? A quiz.

The GBL516 16mm projector used a resistance box.
Article on link below includes picture of the resistance unit.
John
http://www.villagehallcinemas.co.uk/...m_9_gbl516.htm
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Old 23rd Sep 2018, 2:03 pm   #30
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Default Re: What's this? A quiz.

Here's a few pictures of my "toaster".

At full mains it has a resistance of approximately 492 ohms, and at 110 volts approximately 145 ohms.

The last picture is a close-up of the wirewound sheet. How can I determine whether it's asbestos?

Any help much appreciated.

Ps, thanks to raditechman for the link
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Old 23rd Sep 2018, 3:00 pm   #31
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Default Re: What's this? A quiz.

Only lab analysis can confirm whether a material contains asbestos, but from its appearance, I would say with considerable certainty that it is asbestos cement board, widely used in electrical switchgear and heating devices.

Of all asbestos-containing materials, this type of high-density board is one of the lowest hazards. The surface is non-friable and tends to be rich in cement and low in asbestos, and the asbestos present is predominantly chrysotile. Unless it is cut / drilled / filed, it is unlikely to shed fibres. It's basically an electrical grade of the material used in asbestos-sheet buildings.
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Old 23rd Sep 2018, 3:10 pm   #32
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Default Re: What's this? A quiz.

Quote:
Originally Posted by Restoration73 View Post
Many of the early GB (Gaumont British, later Rank) ... I think the early projectors
were actually Bell & Howell made in the USA.
Almost certainly so, there was a definite business connection.
My father ordered a B&H projector direct from the US, which was delivered to the local cinema in a B&H carton, but additionally labelled 'Gaumont'.
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Old 23rd Sep 2018, 4:03 pm   #33
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Default Re: What's this? A quiz.

Thanks dysemo1.

Thanks Lucien, I googled chrysotile and non-friable. Every day is a learning day! The older l get, the less l know.

My intention is to wipe off the dust with a wet kitchen towel and seal the sheet with some PVA.

I'm not going to worry about this as I'm far more likely to die from an excess of malbec!

Cheers!
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Old 23rd Sep 2018, 8:57 pm   #34
MotorBikeLes
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Default Re: What's this? A quiz.

From the photo, it looks to me as if it could be asbestos or asbestos cement board, as Lucien has suggested. However, if it is manufactured say post 1975, it could well be a "fired clay fibre woven board", or ceramic fibre. This came into common use for light weight high temperature insulation during the 1970s. Typical trade names "Triton Kaolwool" (English China Clay I think), Fibrefrax (The carborundum company) and I think there were others. With these, you can see the weave, something like a clean white version of glass wool, with fibres of the same order of thickness. Actual asbestos wool, has VERY fine fibres, which can be further divided almost down to the molecular level, but best avoided.
Les.
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Old 23rd Sep 2018, 10:55 pm   #35
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Default Re: What's this? A quiz.

PVA is a popular candidate to stabilise it particularly if it's in a 'display only' curio.
I haven't been able to establish with any certainty whether it is suitable where it's subject to heat though.
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Old 24th Sep 2018, 10:16 pm   #36
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Default Re: What's this? A quiz.

It was the post war Gaumont British machines that were Bell & Howells built under licence by Rank in Mitcheldean. Although the occasional US built machine did appear in this timeframe such as the model 202 which was the first B&H equipped with magnetic sound. It's British built cousin, the model 630 eventually took over.

Pre-war GB had quite a few different machines, mostly of their own design. The most famous of which is the L516 linked to earlier in the thread. There was one machine, the H16 released at the same time (1938) and based on a US B&H picture head married to a GB amplifier and soundhead. The earlier models C&D were based on Siemens picture heads. Quite why they mixed and matched the product line like this is anyone's guess!

Even when Rank were building machines under licence B&H kept a separate distribution office going. It appears they could still import US equipment if there was no Rank equivalent. The 70DA camera and the 16mm editor are two products that seemed to fall into this category.

Last edited by wd40addict; 24th Sep 2018 at 10:25 pm.
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