Is my transformer damaged?

Hi,

this is my first post on my brand new membership here even though I've been reading threads here for a while. I hope you guys can shed some light on this.

I have a toroid transformer I got from some junk leftover while helping a friend move. The issue is, the junk sat in the rain one day. When I picked it up, it looked like maybe there was some moisture inside the transformer (possibly). From what I understand about how transformers work, that will generally be bad. I'm wondering if it will be ok to use this transformer, if there are any tests I should run, measures I should take etc. I got this thing about 2 weeks ago and the specs are input: 120V~60Hz 0.875A 105W output: 12V 8.75A 105VA

Here's a picture. There's no *apparent* moisture here.
[IMGDEAD]http://www.bramofon.com/piccez/toroid.jpg[/IMGDEAD]

Anyway, thanks for any input your able to give. :)
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
I'm sure it will be fine but what you can do is power it up via a "bulb tester" which is basically a low wattage mains filament bulb in series with the primary. Leave it powered up for 48 hours or so and it should dry itself out (if there is anything there anyway) and it will enable you to confirm the voltages too.

If you search the forums for "bulb tester" you'll see its one of the most widely recommended safeguards for powering up equipment.
 

Elvee

Member
2006-09-08 2:04 pm
I'm wondering if it will be ok to use this transformer, if there are any tests I should run, measures I should take etc.
I would not try to power something in a possibly damp condition, even with precautions: if an insulation begins to fail somewhere, it will spread quickly and ruin the transformer.

This type of transformer generally uses class F materials, but even if it is of a lower class, it should easily withstand 120°C for some hours, the time to remove any trace of humidity.

I would cook it for half a day or so in a kitchen oven set at around 120°C, let it cool down for another half day, and then test it with light bulb tester.
 
Good points, thanks. It also says it has a 125°C. I don't know anything about how those actually work or if going just a little bit high on the temperature could damage something. I have an old oven in an American apartment. I would have to guesstimate the exact temp.
I would cook it for half a day or so in a kitchen oven set at around 120°C, let it cool down for another half day, and then test it with light bulb tester.
Good point. I imagine that mass of wire could hold a temperature pretty well. :)
 

jean-paul

Ex-Moderator
2002-09-20 7:20 am
Germany
I don't know about those mentioned classes but I do know it is not wise to heat it up to 120 degrees when it has PVC insulated wiring (like Amplimo transformers have) and an internal fuse that melts at 125 degrees.

I suppose not much moisture is in it after 2 weeks but either leave it for some more weeks (and then just use it after you tested it with a bulb) or follow Per Anders advice.