It is a VERY old 4.75 Micro FaraD 350V capacitor. It might withstand 1000V for a moment.

 

V.T. = Very Temporarily

 

It looks like an oil filled version, they age well.
Motor run type etc.
Max.

 

This is a very old capacitor.
4.75 micro farad 350V
Where did you find it?

 

Where did you find it?

Probably attached to a motor.

 

V.T. = Very Temporarily

I'm guessing you're joking, and it's Voltage Transient, but what would V.W be ?

 

I'm guessing you're joking, and it's Voltage Transient, but what would V.W be ?

Voltage Working.

 

It may not be that very old. Certainly a few years but not a huge number. And since the label does not say DC, it may be a motor capacitor starting capacitor. Yes, they do usually age well. That one may have been rattling around for a while since it has the paint scuffed a bit.

 

It may not be that very old. Certainly a few years but not a huge number. And since the label does not say DC, it may be a motor capacitor starting capacitor. Yes, they do usually age well. That one may have been rattling around for a while since it has the paint scuffed a bit.

Very unlikely a starting capacitor, those are commonly bi-polar electrolytic, it appears to be a common oil filled paper dielectric RUN capacitor.
They will very seldom deteriorate with age, as the electrolytic variety do.
Max.

 

But seriously...my day job had that kind of capacitor in it, every day, for 36 years. You are looking at something which could be from the 1970's. I can't remember when they quit painting them grey, maybe 30 or 40 years ago. That's my judgement call as a person who has seen thousands of these capacitors over decades of time.

And no, I am not surprised to see an oil filled electrolytic that survived for 50 years. Their failure modes include either a rare internal short (which has a 50% chance of popping the internal fuse) or they rust through and spill the oil. I carried about 40 capacitors in my service truck. When I retired, about 30 of them were the original truck stock from day one. They just don't fail very much.

ps, believe Max. He is correct.

 

This is a very old capacitor.
4.75 micro farad 350V
Where did you find it?

Family friend gave me a bunch of his old electronic supplies and parts, it wasn’t connected to anything and just in a box with a bunch of other stuff. Absolutely no idea what it was for or why I have it.

 

Very unlikely a starting capacitor, those are commonly bi-polar electrolytic, it appears to be a common oil filled paper dielectric RUN capacitor.
They will very seldom deteriorate with age, as the electrolytic variety do.
Max.

Interesting, what do run capacitors do? I’m new to the motor world, as you can probably tell from my recent questions

 

But seriously...my day job had that kind of capacitor in it, every day, for 36 years. You are looking at something which could be from the 1970's. I can't remember when they quit painting them grey, maybe 30 or 40 years ago. That's my judgement call as a person who has seen thousands of these capacitors over decades of time.

And no, I am not surprised to see an oil filled electrolytic that survived for 50 years. Their failure modes include either a rare internal short (which has a 50% chance of popping the internal fuse) or they rust through and spill the oil. I carried about 40 capacitors in my service truck. When I retired, about 30 of them were the original truck stock from day one. They just don't fail very much.

ps, believe Max. He is correct.

Wow, vintage stuff.

 

Absolutely no idea what it was for or why I have it.

Kleptomaniacs use to say the same when questioned at the police station.

 

Interesting, what do run capacitors do? I’m new to the motor world, as you can probably tell from my recent questions

In conjunction with a dedicated motor winding they provide the phase shift needed in order for the motor to run, otherwise if just the main winding were used, it would result in 180° commutation which would not achieve any rotation (single phase).
Max.

 

Kleptomaniacs use to say the same when questioned at the police station.

that’s a good one. No definitely didn’t find it in that box of electronics I stole for 3 door so down because their garage was open

 

In conjunction with a dedicated motor winding they provide the phase shift needed in order for the motor to run, otherwise if just the main winding were used, it would result in 180° commutation which would not achieve any rotation (single phase).
Max.

Oh cool, cool. I don’t thibk I have any use for this, but might as well hang onto it for kicks I guess

 

that’s a good one. No definitely didn’t find it in that box of electronics I stole for 3 door so down because their garage was open

Do not worry. You are not alone.
Yesterday, I run my five yearly drawers tidy up and run across several items which the sentence also applies to.

 

Do not worry. You are not alone.
Yesterday, I run my five yearly drawers tidy up and run across several items which the sentence also applies to.

View attachment 206644View attachment 206645

Those green things look like the, "green dot diodes" used in Sears TV's in the 1960's. We replaced them like popcorn after every lightening storm.

@Cyrus Mingley 4.5uf is an odd size, even if you're in the business. It's probably good as a door stop, unless you want to use it for a 2 amp limiter in a 120 VAC, 60 Hz circuit. Hint: That's how we test them. Connect a 120 volt power cord directly on their terminals and see if the result is 2 amps. For some reason, they don't respond well to modern capacitance testers. That's why a real world application of full power line voltage is the right way to measure them.