On Mon, 2011-03-14 at 17:58 +0100, Peter Blodow wrote: ... snip > A capacitor connected to one leg of the two-phase system produces a 90 > degree phase shift relative to this lead. Using this as a mock three > phase system, you will have 180 + 90 +90 degrees for a revolution > including a direction information, depending to which leg you connected > the capacitor. The distribution is uneven which is the reason for > reduced power, but better than nothing. Don't confuse this with a > starter capacitor used to supply a direction information to a generic > two phase motor! Those are for short time use with small motors only and > blow their tops when used continously (because of faulty starter relay > or so).
In case my attachment doesn't go through, here is my graphical study of a rotary three phase converter: http://www.wallacecompany.com/machine_shop/EMC2/three_phase_converter-1a.png The 180 degree voltage phase shift is only an issue if neutral is used, but it is not. I think the decrease in efficiency is due to using one phase to try to generate two more and the currents are much higher than normal. (Viva VFD's) -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
