You are correct. MOVs are what I was primarily thinking of and my fingers typed transorb. I too have seen transorbs fail in automotive based applications and my mind probably extrapolated to both. I will look around to see if I can find anything relating to transorbs directly for the degradation. Load dumps in cars and trucks can cause surges A LOT higher than expected ie 200volts for 20 ms on a 24 V system in a transit bus when the AC cycled. Larry ---- Dwayne Reid wrote: > At 07:55 AM 2/6/2006, Larry G. Nelson Sr. wrote: > >You do not want to use a transorb for a repetitive application like > >this. Transorbs have a limited life. Every spike they see shortens > >this life. When they fail, and they will, they usually fail shorted > >causing even more problems. > >Larry > > Hi there, Larry. > > Can you point me to some data that supports this? I know that MOVs > have an associated wear factor but I've NEVER seen anything similar > that in regards to a Transorb. > > I use a LOT of Transorbs in various places and the only failures I > can associate with them is when dealing with severe load dump issues > in heavy earth-moving machinery. Subsequent investigation revealed > that the peak power ratings on the failed devices were exceeded by at > least an order of magnitude. In other words, not the fault of the TVS. > > But I've not aware of any "wear" issues with TVS devices and would > very much like to confirm or deny that. > > dwayne > > -- > Dwayne Reid > Trinity Electronics Systems Ltd Edmonton, AB, CANADA > (780) 489-3199 voice (780) 487-6397 fax > > Celebrating 22 years of Engineering Innovation (1984 - 2006) > .-. .-. .-. .-. .-. .-. .-. .-. .-. .- > `-' `-' `-' `-' `-' `-' `-' `-' `-' > Do NOT send unsolicited commercial email to this email address. > This message neither grants consent to receive unsolicited > commercial email nor is intended to solicit commercial email. > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist