Identify a part

Thread Starter

VanSkulk

Joined Feb 7, 2021
3
Hi, I would like help identifying a part I found in a bin full of parts.
PXL_20210206_213143385.png PXL_20210206_213156994.png
I found something similar searching the net. The site calls it a "AR2 Overload protector" (http://wuyuetech.com/En/Product-17.html)
Picture1.png
I guess it is an overload device, but overloads that I am familiar with have a reset. If this is an overload, how does it work?
 

geekoftheweek

Joined Oct 6, 2013
641
Circuit breaker / self resetting fuse. Similar can be found in auto parts stores, sometimes without the mounting holes. It has metal strips of different materials that heat up and bend on overload to break contact. One material will expand more than the other causing the strips to bend and break contact. As the strips cool they relax back into place and contact is once again made.

Edit
https://en.wikipedia.org/wiki/Bimetallic_strip is a bit more detailed
 
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Thread Starter

VanSkulk

Joined Feb 7, 2021
3
Thanks for the responses everyone.

geekoftheweek, that sounds like a good possibility. You sound pretty confident in your statement. Are you fairly certain or just making a good guess?

Even though the item I found on the net is labeled as an overload and has similar markings, it also has 3 contacts rather than 2 and a much lower amperage rating.
 

Tonyr1084

Joined Sep 24, 2015
5,976
The two contacts close by each other appear to share the same rivet. It's probably a convenience to have the extra spade lug. As for amperage rating - overload protection comes in all values. The bigger ones are likely to have large terminals such as the 50A fuse. Small spade lugs aren't going to handle that much current.

And trust the ratings, even the voltages. DC current is a lot hotter than AC current. That's why it's rated for
50A at 125/250VAC
or
50A at 12/24VDC

As for the 50 amp fuse - I can't tell you why one says BAT and the other says AUX. But I'm sure there's a reason.
 

geekoftheweek

Joined Oct 6, 2013
641
geekoftheweek, that sounds like a good possibility. You sound pretty confident in your statement. Are you fairly certain or just making a good guess?
I am very confident. Actually used to work with them fairly regular on some older trucks at work. 10A to 50A seemed to be the range of ratings I remember seeing.

The BAT and the AUX markings have to do with how the current flows. There are also type 1, and type 2 varieties. Type 1 will reset automatic while type 2 either needs to have the load removed or power turned off to reset. I've never had one apart to find out just how they work, but they all were designed around the metal strips idea. It will probably work no matter which way it's wired, but will work best if wired so power flows from BAT to AUX.
 

Thread Starter

VanSkulk

Joined Feb 7, 2021
3
Great! Thank you geekoftheweek!

The part is now labeled and waiting to be put into service.

I don't actually have any memory of the part specifically, but my best guess is that it was part of an attempt I made years ago to install an inverter in my van. I didn't know what I was doing and although it worked, it never worked well. I've learned a lot since then and I'm currently looking at several automotive projects, so I will no doubt find a place for it in the near future.
 
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