Trying to identify a specific capacitor

Thread Starter

master_mugen_san

Joined Sep 14, 2020
4
Hi,

I hope this is in the right section... I work in a fablab and during a repair café I was hosting, someone came with an appliance that had had a current surge. The only component that seemed affected was the capacitor in the picture. We thought replacing it would do the trick but I'm unable to identify it...

If someone recognizes it I'd be grateful! Many thanks :)

capacitor.jpg
 

sagor

Joined Mar 10, 2019
251
I agree, MOV. I suspect the first 07 is the diameter (mm), The second line is the rated voltage, hard to see, but the 75 at the end should give a clue and compare tables of MOVs to that number and to the input voltage. MOV are usually rated 2 to 3 x the input voltage. Last line of digits is usually the date code or manufacturer info.
The real issue is that the MOV fired with the voltage surge, but there is a possibility there is other damage. The MOV can only handle so much before it "cooks" itself. In some cases, the MOV works, and things are fine. If the MOV gets over stressed, it "blows up" and becomes open, with the surge often going to other components. Check everything carefully.
 

DickCappels

Joined Aug 21, 2008
6,590
Indeed, the MOV might be fine -they are designed to dissipate a lot of power for a short time. If your appliance is not working it might be that the overload blew a fuse.
 

MrChips

Joined Oct 2, 2009
21,869
Interesting.
The MOV is designed to protect the appliance from short duration voltage surges. If the MOV failed it would fail either open circuit or short circuit.

If the MOV is shorting then the main AC LINE input fuse would blow.
If the MOV is open then the appliance should still function without surge protection.

Edit: Dick beats me to it.
 

MrChips

Joined Oct 2, 2009
21,869
Does the AC plug have a built-in fuse?
Use an ohmmeter and check for continuity between the AC plug prongs and the inputs to the circuit of the unit.
What is the appliance?
 
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