On Tue, 21 May 2013, Gene Heskett wrote: > Date: Tue, 21 May 2013 17:14:23 -0400 > From: Gene Heskett <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: [email protected] > Subject: Re: [Emc-users] Superglue, or Loc-tite for that motors flywheel? > > On Tuesday 21 May 2013 17:12:44 Peter C. Wallace did opine: > >> On Tue, 21 May 2013, Jon Elson wrote: >>> Date: Tue, 21 May 2013 12:07:44 -0500 >>> From: Jon Elson <[email protected]> >>> Reply-To: "Enhanced Machine Controller (EMC)" >>> >>> <[email protected]> >>> >>> To: "Enhanced Machine Controller (EMC)" >>> <[email protected]> Subject: Re: [Emc-users] Superglue, >>> or Loc-tite for that motors flywheel? >>> >>> Peter C. Wallace wrote: >>>> PS: we blew a couple 75A 1200V Darlintons trying to make a constant >>>> current dynanometer load, so the lesson about secondary breakdown (or >>>> FBSOA) kinda sticks with me :-) >>> >>> I had a fantastic chat with an IR engineer about the characteristics >>> of IGBTs. >>> He said to never let them operate in the linear region, even for >>> sub-us periods. The positive temp coefficient of the basic element >>> in the linear region will cause current hogging to the center of the >>> die, and so just the center elements will be conducting all the >>> current until full saturation occurs. This will destroy the device >>> very quickly, sometimes within a few microseconds! >>> >>> Jon >> >> Interestingly SiC BJTs seem relatively immune to secondary breakdown >> (positive temperature coefficient of resistivity vs Si's negative) >> This also means they parallel well. >> > Si Carbide? I wasn't aware that anyone was using those for more than lab > curiosity. > > In production AND affordable?
Asking for both is a bit optimistic :-) http://www.fairchildsemi.com/products/sic-bjts/ has a little info on upcoming products and Cree has been shipping SIC MOSFETs for a while (80 mOhm 1200V ~$30 each 160 mOhm 1200V ~$15 each) These MOSFETS have characteristics that are simply unobtainable with Si Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Try New Relic Now & We'll Send You this Cool Shirt New Relic is the only SaaS-based application performance monitoring service that delivers powerful full stack analytics. Optimize and monitor your browser, app, & servers with just a few lines of code. Try New Relic and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_may _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
