Varistor or Transient absorber

I would first look to see if Mouser carries it, as they have good refernces to manufacturers. Second place is DigiKey. Try them.....

--- I think you're right. With the prefix "ZNR", though, it's probably a Zener Transient Voltage Suppressor (TVS). I'd guess that "10221" stands for the clamping current (10A) and voltage (220V, with 22 being the first two significant figures and 1 being the number of trailing zeroes.) lot of MOV's and TVS's have a part number indicating the clamping voltage and current and yours seems to be a 10A 220V device.

Google for Varistor or TVS and you'll get a lot of hits, then take a look at part numbers with 10 and 221 (or 220) in them to get an idea of whether what you have matches anything.

-- John Fields

Great detective work.

These high voltage protectors are usually MOV technology, especially if it is a big flat disk format.

Regards,

Bill

It's what we call a MOV (Metal-Oxide Varistor), generically called a ZNR. You can replace it with a similar type of the same diameter disk (10mm? and rated for the appropriate voltage. If this is a 120VAC nominal supply, a 220V rated (221) varistor would be about right, but that's just a guess. (Varistors are sometimes rated by DC voltage, sometimes AC, and sometimes both!.

Best regards, Spehro Pefhany

It's what we call a MOV (Metal-Oxide Varistor), generically called a ZNR. You can replace it with a similar type of the same diameter disk (10mm? and rated for the appropriate voltage. If this is a 120VAC nominal supply, a 220V rated (221) varistor would be about right, but that's just a guess. (Varistors are sometimes rated by DC voltage, sometimes AC, and sometimes both!.

Best regards, Spehro Pefhany

It's what we call a MOV (Metal-Oxide Varistor), generically called a ZNR. You can replace it with a similar type of the same diameter disk (10mm? and rated for the appropriate voltage. If this is a 120VAC nominal supply, a 220V rated (221) varistor would be about right, but that's just a guess. (Varistors are sometimes rated by DC voltage, sometimes AC, and sometimes both!.

Best regards, Spehro Pefhany

Hi

If its in a mains filter feeding the unit, it should work fine without it, tho with a bit less protection and thus a bit less expected MTTF. Just so you know the options.

Regards, NT

Yes, and it's unlikely that the OP "blew" it, as he put it, if it's on the input side. This is typically the result of one too many transient into the MOV. One way you could affect this would be to put an inductive load such as a motor or transformer in parallel with the input of the SMPS and switch the two with a series switch. The typical failure mode, in any case, is a low resistance leading to very high power dissipation, burning, and, eventually, a high resistance, though the fuse may go before that happens.

Best regards, Spehro Pefhany

Right. I'm having second thoughts tho: if its been cooked due to spikes, maybe it should be replaced before further PSU use after all. And not switched on with an inductive load in future.

Regards, NT