On 31.07.16 12:01, Gene Heskett wrote: > > Here is one of that general appearance, without the motor on the top. > > <http://www.ebay.com/itm/3-PHASE-POWERSTAT-VARIAC-15-AMPS-7-3KVA-240-VOLTS-IN-0-280-VOLTS-OUT-/122032051715?hash=item1c69ad5603:g:W1oAAOSwkl5XdaiB>
Very nice - it'd make 3 single phase variacs for those of us who only have that. To protect the back against having to lug such a monster, there's always the option of tuning a driven induction heater off resonance when the heat-treatment temperature is approached, I figure. This guy shows a circuit (only semi-legible) of a unit he's using at only 500W, to take a nut to 1400°C (2552°F): (Though I'm not keen to muck with a 300 Vdc power supply.) https://www.youtube.com/watch?v=WqEajWAuRfM That low power level ought to be ample for heat treatment of modestly sized parts, and is clearly achievable at much safer supply voltages. An IRF half-bridge driver plus a couple of HV MOSFETs or IGBTs would only need a 555 for variable frequency drive. (I don't have an IR2153, which does both jobs in one chip.) Erik ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
