I was wondering if I could get an ID on what exactly this unit might be. I have a customer asking for a refurbished duct heating unit and one of these was attached to it. The best guess here is that it is some sort of high voltage DC thermal fuse. The two big wings on either side house magnets, likely to draw arc flash. If anyone can help out, that would be great.

 

Well I've never seen one like that before but I'd tend to agree with your assessment. How is it connected in the circuit? I wouldn't have expected high voltage DC in that application.

 

I have been working with duct heaters for 40 years, and I've never seen a DC heater. However, there are meltable (fusible) links that we use on 5KW heaters with a 230V AC supply.

 

Thanks for the help gents. I found out from a co-worker in our R&D lab (a walking encyclopedia of obscure heating components) that this is indeed a high voltage DC thermal fuse / fusible link. Apparently only one company in the world (Vapor Rail) makes these. The magnets are indeed to extinguish the arc when the unit blows.

 

Do you mean the one in Canada?

http://www.ic.gc.ca/app/ccc/srch/nv...ile=cmpltPrfl&profileId=501&app=sold&lang=eng

http://www.profilecanada.com/companydetail.cfm?company=133271_Vapor_Rail_Saint-Laurent_QC