2012/1/12 andy pugh <bodge...@gmail.com>: > On 12 January 2012 15:43, Viesturs Lācis <viesturs.la...@gmail.com> wrote: > >>> On reflection, it might be wise to use a DC/DC convertor for Vdd, > >> And how much would such a convertor cost? I would need to convert >> 330VDC to 12VDC. > > I was meaning a 12 to 12 (or 12 to 15) one, like > http://uk.rs-online.com/web/p/dc-dc-converters/6727408/ > > That gives the IRAMS board an isolated 15V supply,
Thanks for the link! > But You probably want > to consider Pete's advice. Oh yes, I really would like to do that. Unfortunately I do not have much of a choice to get those motors running. So it is just one more case, where I will have to learn things the hard way. So I understand that it is required to: 1) insert optoisolators in PWM signal lines to insulate controller from the chip, I checked that optocouplers have Vrms = 2500 V; 2) I can use any external PSU as long as I insulate it from the chip with a DC-DC converter, DC converter's output is connected to Vdd and Vss, keeping it insulated from rectified motor power supply, DC converter in Andy's link has isolation voltage 3000 VDC; 3) connect rectifier (220VAC to 330VDC) output to: +330 VDC to V+ GND to LeU, LeV, LeW I pasted the schematics here: http://picpaste.com/chip-cgYQizaV.JPG Is 1:1 transformer needed for rectifier AC input to insulate from the AC supply? Viesturs ------------------------------------------------------------------------------ RSA(R) Conference 2012 Mar 27 - Feb 2 Save $400 by Jan. 27 Register now! http://p.sf.net/sfu/rsa-sfdev2dev2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
