On Fri, 2012-06-15 at 10:53 +0100, andy pugh wrote: > On 15 June 2012 06:58, Viesturs Lācis <viesturs.la...@gmail.com> wrote: > > > Unfortunately it requires relatively larger power supply with higher > > current output. > > This is a problem with motors like the Keling ones, with a 48V rated voltage. > It is far simpler to make a 300V PSU than a 48V one. Simply rectifying > mains voltage into a big capacitor makes a PSU that the 8i20 is happy > with. > > Those Keling motors have a 500V / 1 min rating. I don't know if that > meas that they can run indefinitley on a 300V PWM (with a 48V > "average" or not). In the US I suppose a rectified-mains PSU would be > around 150V which sounds more reasonable. (only 3x rated voltage, and > it is conventional to run steppers at that sort of overvoltage) >
48 Volts or rather -48 Volts DC is common for telephone equipment, so there may be cheap supplies available, if one knows where to look. Building an Antek supply shouldn't be too expensive, but I haven't checked prices recently. http://www.antekinc.com/index.php http://www.antekinc.com/gview.php One could make a transformer for the needed voltage, like these guys did. http://mackys.livejournal.com/838591.html Brushed motors (and drives) might be cheaper and universal motors are usually wound for mains voltage. If they can be modified for permanent magnets, universal motors could be handy. http://www.supermagnetman.net/index.php?cPath=37&page=3 For most of us, brushes wear well enough to not be a maintenance problem. Scrap yards should have a large supply of vacuum cleaner motors from people that don't know how to replace a rubber belt. Another thing I haven't had time to look into is using a Delon doubler when one needs higher voltage than what is at hand. http://en.wikipedia.org/wiki/File:Bridge_voltage_doubler.svg http://en.wikipedia.org/wiki/Voltage_doubler -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
