High voltage/current Polyswitch-type device?

[I tried this out on sci.electronics.components and didn't get a response, so I figured I'd try here...]

Does anyone know of an auto-resetting fuse-like device that'll handle 120V @

5A or thereabouts? I've used Raychem PolySwitches in the past, but their 120/240V product offers
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only go up to 1.4A.

Thank you,

---Joel Kolstad

Reply to
Joel Kolstad
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Hello Joel,

Give Weidmuller a call. They have (or at least used to have) breakers that could somehow control themselves, signal that a trip had occurred and be controlled remotely. Probably not cheap, but if they don't have anything chances aren't that great that it exists elsewhere.

--
Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

On Mon, 10 Jul 2006 20:55:12 GMT, Joerg Gave us:

A Polyswitch is a SMALL discreet device. I suspect that the "breaker" you are suggesting weighs more than his entire design.

Reply to
Roy L. Fuchs

Read the plastic PTC datasheets carefully before you use them any any serious voltage. The ones called "200V PTC" on the front of that data sheet often are really limited to something like 60V in actual use.

If you can withstand the losses, a ceramic PTC may be better from your application, if you can find one. They tend to have a higher untripped resistance, and a softer knee but also a higher voltage rating.

--
--
kensmith@rahul.net   forging knowledge
Reply to
Ken Smith

Hello Roy,

Yes, they are about as large as a regular breaker. They actually have to because they are mounted into the same kind of boxes. Just wanted to mention these in case Joel finds himself between a rock and a hard spot, where he can't find anything Polyswitch style at 5 amps but must offer the protection. Could do it with a discrete circuit as well if it's for a larger series.

--
Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

Hello Ken,

Good point, I have seen some of these do the 4th of July thing.

I don't know if they are still made but in the early days of TVs the sets contained power resistors that had a spring-loaded thermal release. I considered them kind of dangerous because it was basically a spring loaded solder joint, splattering off solder when they opened. But they did work.

--
Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

Thanks for the idea, Joerg. It looks like we are just going to use fuses (internally) and one of those combined IEC power entry/filtering/breaker modules on the back of the chassis.

Reply to
Joel Kolstad

Hello Joel,

There are also very small breakers, about the size of a toggle switch but 1.5 - 2 inches long. I forgot the brand I used but it was one of the main European breaker mfgs, Schurter or something like that. Sometimes you see these in ovens where an outlet must be limited to 15 amps while the oven itself is hooked up to 30 or 40 amps. They come in various sizes, IIRC I used one rated at 6 amps.

--
Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

Years ago in the days of hybrid CTVs I remember one that had this type of fusible resistor in the metal enclosure round the line O/P valve, there was a warning label on the enclosure to use only low melting point cadmium solder - and a little plastic clip holding a coiled up length of solder for resetting the fusible resistor!

Reply to
ian field

Hello Ian,

Courtesy doesn't go that far anymore these days. When the thermo-fuse of our hot water dispenser gave out I looked around everywhere in it, in hopes of finding a spare. Nope. Had to drive 80 miles round trip for a $1.15 part.

--
Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

I remember being very surprised as a kid the first time I found a device that said, "User Serviceable Parts Inside" -- at first I thought I had mis-read it, since up until that point I'd only ever seen the ubiquitous, "No user serviceable parts inside!" -- The device in question was a tube radio from the '60s that my mother had obtained in Germany as a student.

---Joel

Reply to
Joel Kolstad

Hello Joel,

I've got a few of those, some from Germany and one from Australia. The ones from Germany would make the guys in the legal department of "modern" companies cringe. Not that they weren't built well but their manuals contained detailed instructions on how to rewire the transformer to other line voltages, admonitions to switch to the correct fuse size, and all all that happening right next to an electrolytic charged to a good 300VDC.

Oh, and then I have one that runs sans transformer. All that would be between you and possible electrocution is a rubber foot that falls out or an antenna cap shorting out.

--
Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

I hope that you bought a spare while you were there. :)

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
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Reply to
Michael A. Terrell

Hello Michael,

Yes, Sir. I did.

And I even know where I put it :-)

--
Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

Good man! :)

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
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Reply to
Michael A. Terrell

On Tue, 11 Jul 2006 12:47:55 -0700, "Joel Kolstad" Gave us:

The use of Power Entry Modules are good practice for AC fed products.

Reply to
Roy L. Fuchs

PTC devices can be operated safely in parallel to achieve higher let-through currents.

Epcos offers a range of higher voltage PTCs, but 5A is a bit much for any higher-voltage device.

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RL

Reply to
legg

Thanks, I had thought of that and wasn't sure whether or not it was acceptable to do so.

Perhaps 3 or 4 of the Raychem 1.4A ones would work well...

Reply to
Joel Kolstad

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