Post by thread:[EE:]Re: High current PCB

Have you looked at the number of fet's you'll need or even the basic power requirements/cooling of your system? 12*1000A = 12kW! some of the best (1000A ) fets I've used are still 6mohms .. which is 6 volts dropped across one fet. even if you use 10 that's still 1000*1000*.0006 =600W dissipated in the fets. I'd use a relay. Richard {Original Message removed}

On Fri, 30 Jan 2004 06:17:31 -0000 spacecat <spam_OUTspacecatTakeThisOuT450SE.CO.UK> wrote: > Have you looked at the number of fet's you'll need or even the basic power > requirements/cooling of your system? > 12*1000A = 12kW! > > some of the best (1000A ) fets I've used are still 6mohms .. which is 6 > volts dropped across one fet. even if you use 10 that's still > 1000*1000*.0006 =600W dissipated in the fets. True, but at 60 watts per FET, this shouldn't be too bad to dissipate with a standard heatsink and/or fan setup. Not overly efficient, but... Eric > > I'd use a relay. > > Richard -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body .

Also remember that the arcing that you say will kill the Contacts will also kill the FET. You'll need a freewheeling diode of a similar spec to the FET or a large snubber. If a snubber/diode can keep the voltage below the voltage rating of the FET (30~60V), that would also stop arcing on a contactor. {Original Message removed}