Hello and thank you in advance. A friend of mine picked this up while out scrapping one day. It came in a homemade box made out of old fiberboard. At first i thought variac, then I did some research and came up with variable resistor/rheostat. I feel like its some kind of transformer, but I haven't applied any power to it. I would like to find a way to use it if possible so any information would be appreciated.

 

Welcome to AAC!

I did some research and came up with variable resistor/rheostat. I feel like its some kind of transformer, but I haven't applied any power to it.

It looks like a rheostat to me.

It's inadvisable to apply power to some unknown component. If it's a transformer, you can use an ohmmeter to identify the windings. If it's a rheostat, you can measure the resistance.

 

It appears to have a laminat3ed steel core, so a variable inductance, choke etc.

 

Variable transformer?

 

It appears to have a laminat3ed steel core, so a variable inductance, choke etc.

It looks to have a inner coil so it seems to be a transformer of some sort.

 

It looks to have a inner coil so it seems to be a transformer of some sort.

Early 'Variac' ?

 

I agree with dl324
I reckon it is likely to be a rheostat - used as an early form of mains light dimmer

I used these at school to raise and lower light levels for spot lights during amateur dramatics performances.

Would need closer examination to be sure

 

Early 'Variac' ?

Just a WAG on what I see.

My guess evidence is the presence to two different sizes of wires of opposite sides of the device like a step-X transformer. The old school fiber wiring insulation seems to indicate larger gauge wires on the top coil loop than the thinner wires to a possible inner coil loop. The wires to the two slider taps looks to be modern plastic insulation soldered to the taps for some later application of the device.

Physical examination with a multi-meter is needed to be sure.

 

Welcome to AAC!
It looks like a rheostat to me.

It's inadvisable to apply power to some unknown component. If it's a transformer, you can use an ohmmeter to identify the windings. If it's a rheostat, you can measure the resistance.

Welcome to AAC!
It looks like a rheostat to me.

It's inadvisable to apply power to some unknown component. If it's a transformer, you can use an ohmmeter to identify the windings. If it's a rheostat, you can measure the resistance.

Thank you Dennis.
I did take the multimeter to it and should have posted that. The two large wires which could be the "primary" .5ohm and had continuity from both wires to both of the sliding contacts. the 2 small wires at the other end don't seem to have continuity, so no reading from them. they were connected to an old non polarized mains plug when i got it.

 

I did take the multimeter to it and should have posted that. The two large wires which could be the "primary" .5ohm and had continuity from both wires to both of the sliding contacts. the 2 small wires at the other end don't seem to have continuity, so no reading from them. they were connected to an old non polarized mains plug when i got it.

A transformer needs to have at least 2 windings.

 

Thank you Dennis.
I did take the multimeter to it and should have posted that. The two large wires which could be the "primary" .5ohm and had continuity from both wires to both of the sliding contacts. the 2 small wires at the other end don't seem to have continuity, so no reading from them. they were connected to an old non polarized mains plug when i got it.

For my guess that seems to mean it's bad (open in the primary) to me as the two wires connected to the mains plug would be the primary and the 0.5 coil would be the secondary in a step-down transformer.

 

Here are couple pics of the bottom.

 

I used these at school to raise and lower light levels for spot lights during amateur dramatics performances.

We had one in our school lab also, but it did not have the laminated core, it was usually used for DC dimming/experiment only.

 

We had one in our school lab also, but it did not have the laminated core, it was usually used for DC dimming/experiment only.

Another WAG.

I've seen mag-amps used as light dimmers long ago. That's another (lesser) probability here that this device is part of one.
https://www.sunpower-uk.com/glossary/what-is-magnetic-amplifier/