Right, Amprobes can only measure absolute current. Theorectically a load could draw 10 amps at 230 volts and it would not spin your power meter at all if it had a power factor of zero.
But that is pretty much impossible. If the power factor was 50% then the total watts being consumed and registered on you meter would be 10 amps x 230 volts x .5 (50% power factor). Dave On 4/3/2011 5:29 PM, gene heskett wrote: > On Sunday, April 03, 2011 05:22:28 PM John Thornton did opine: > > >> I run my lathe and mill from it. The lathe is about 7.5hp spindle and >> the mill is about 7.5hp spindle. And of course it is so convenient I >> just turn it on when needed and off when not. My EMC machines the >> computer is on 120vac so I only need the phase converter on when >> machining. I just checked and the single phase side draws 9 amps when >> idling and 9.5 with the lathe spindle spinning with no load at 2k. >> > If using an 'AmProbe' like device to measure that, I suspect some reactive > power is registering to it, that likely is not registering at the power > meter itself. But thats more of a common sense feeling than anything else > since it isn't terribly convenient to clock the meters disk and translate > that to KWH. It could be done I guess, given a big enough curiosity bump. > > >> I'd >> say it is more efficient than paying the local coop to run 3 phase a few >> miles back into the woods to me from the highway. >> > Chuckle, for the first 30 years anyway. :-) By then you'll probably have > solar and wind and be off the grid because its cheaper than petrol power. > > >> On my BP Series 1 I >> use an Automation Direct GS2 VFD as it is only 1.5hp for the spindle and >> they are cost effective way to get up to 3hp 3 phase from single phase. >> > I'd have to agree, and wish I had that big a mill, sniff... > > >> John >> >> gene heskett wrote: >> >>> On Sunday, April 03, 2011 10:46:26 AM John Thornton did opine: >>> >>>> John, >>>> >>>> I think it is finally done... sorry for the delay. >>>> >>>> http://gnipsel.com/shop/rpc/rpc.xhtml >>>> >>>> John >>>> >>> How efficient would you say this is John? I can lay my hands on a 15 >>> hp 3 phase motor for the base iron. >>> >>> And how big a 3 phase motor could be operated from it? >>> >>> I would have a hard time justifying an idling current draw of 35 amps >>> a leg from the 240 to run a 3 horse motor on the machine. >>> >> ------------------------------------------------------------------------ >> ------ Create and publish websites with WebMatrix >> Use the most popular FREE web apps or write code yourself; >> WebMatrix provides all the features you need to develop and >> publish your website. http://p.sf.net/sfu/ms-webmatrix-sf >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > > ------------------------------------------------------------------------------ Create and publish websites with WebMatrix Use the most popular FREE web apps or write code yourself; WebMatrix provides all the features you need to develop and publish your website. http://p.sf.net/sfu/ms-webmatrix-sf _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
