Frankenstein's been robbed!! - ECN Electrical Forums

Pictures and info supplied by napervillesoundtech:

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I was working in an old wiring closet in a school, and came across this. They gave it to me, along with another weird board (another set of pics). I am not sure what it is. The shaft tightens with a little bolt and can be raised and lowered. It also looks like it has some sort of capacitors on it. I have not plugged it in; however, I did drag it back to my shop and test it with an ohmmeter. There is a complete circuit through everything. I just thought you might get a kick out of seeing it.

Thanks Ben.

[This message has been edited by Trumpy (edited 03-02-2006).]

The device with the movable plunger looks to be a variable inductor. By changing the depth of the core, you can vary the inductance in the circuit.

Perhaps a science lab demonstrator for the concept of electrical resonance? At one particular setting, some bulbs will dim while others get brighter?

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Perhaps a science lab demonstrator for the concept of electrical resonance?

I'd second that. It seems to be the most likely purpose.

Here's the schematic. I agree - it's a resonance demo. I would like to see a transformer there to limit the chance of zapping anyone, though...

[Linked Image from barc.org]

[Edited to fix typo in image URL...]

[This message has been edited by n1ist (edited 03-03-2006).]

Great to see this old stuff,
my guess is that it is probably 1920's.
I have to agree with the other comments that it is probably from a science class and used for showing students what a variable inductor does and a capacitor in series with an electrical lamp circuit.
What are the voltages from the lamps ?
110 Volts or different ?
It looks like there are 3 capacitors on top of each other in parallel. they may have been used as singles too to show the different brightnesses of the lamp with different cap. values.

Too bad the caps appear to be leaking, it would be fun to power this puppy up and see it in action.

The caps may be replacable if the values haven't been painted over.

Keep this setup in mind in case you know of any young ones who are trying to learn about electricity....

If I were a physics tteacher, I'd want to use this in the lab. But first I'd enclose it in a clear plastic box to avoid the shock hazard. The variable inductor's control handle would poke thru a hole in the top of the box so the students could safely play with it. And that cap probably needs to be replaced.

The caps are surrounded by a thin metal shield, which has a thick coating of black paint on it. I think if I pull that shield off, I may be able to see the values on the caps. I too am a little curious as to how well this works.