Variac core integrity....cracks?

jpanhalt

Joined Jan 18, 2008
11,087
Presumably, it is a core to an inductor. Yes, cracks can affect performance (example a gapped vs. non-gapped toroid).
Have you plugged it in? How does it work? Does it give expected output? Does it overheat?

I wouldn't worry about cosmetic blemishes on a Variac. You should see some of mine rescued form the trash bin. However, none are cracked like that that I know of. I just use them.
 

dendad

Joined Feb 20, 2016
4,452
Just for a test, with it unplugged!!!!
Can you poke a fine probe down the crack to see if you can figure out if it is the core or just a plastic of some sort covering the core?
If the crack goes a long way down, it may be the core, but if it is just a few mm deep, then it probably is a cover.
Also, when it is plugged in, does it draw lots of current? A crack in the core with a gap will lower the inductance a fair it so I would expect the current to increase.

You may be able to poke a couple of pins down the crack to see if you and measure a resistance between them of an iron core too.
But I think the primary current test will tell all.
 

Thread Starter

KN4RUI

Joined Apr 3, 2019
6
Thank you for your help.....this just arrived from flea bay and this is initial inspection. Guess I will power it up and stand back!....should it work for me..might I consider an epoxy to the crack line...or jb weld...marinetex...etc?
 

MaxHeadRoom

Joined Jul 18, 2013
28,621
Thank you for your help.....this just arrived from flea bay and this is initial inspection. Guess I will power it up and stand back!....should it work for me..might I consider an epoxy to the crack line...or jb weld...marinetex...etc?
If the unit works, just fill it with JB weld.
May stop the ingress of anything undesirable.
Max.
 
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