Hi Kirk; Answers below. On Thu, 2011-02-03 at 12:50 -0800, Kirk Wallace wrote: > On Thu, 2011-02-03 at 14:34 -0500, Don Stanley wrote: > > Hi All; > > I am attempting to configure EMC2 10.04.06 to control RPM > > on a 60 HZ AC generator. > > I am hoping to control my Onan with EMC2 someday: > http://www.wallacecompany.com/machine_shop/Onan_5CCK/ >
>Oops, I completely missed the point of the question. I know it would be a big help if, I would ask the question you answered. Sorry, I couldn't help it. (LOL) >I think this should work: >http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Closed_Loop_Spindle_Speed_Control<http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Closed_Loop_Spindle_Speed_Control> I believe it will. Going to check it out next. >Don, are you going to try doing voltage regulation too? I seem to recall >there are some non-obvious situations that the expensive regulators >guard against. Something to do with sudden changes in load causing burnt >out rotors or race conditions. The generator has very good regulation on each of the 3 phases. >Oh and for my encoder velocity suggestion, the PID error could be feed >to stepgen's velocity mode. I am hoping this will also eliminate the over speed catch up problem as well as the throttle quiver. On Fri, Feb 4, 2011 at 12:53 AM, Kirk Wallace <[email protected]>wrote: > > The way I see it, the lag between the input throttle change and the rate > of RPM correction should not be too much of a problem. The frequency > regulation won't need to be more than +/- a few percent, the correction > can take up to a second, and overshoots are allowed. A problem I have > seen on a similar setup was a self energizing oscillation due to very > poor PID tuning. > > Another problem that comes to mind, if the load suddenly increases the > throttle can open quickly and drop the vacuum too far and cause a stall. > It might be wise to also have a vacuum sensor to guard against the > throttle opening too far. It might also be good to have the throttle set > to idle or a start position until a valid vacuum is sensed. Low vacuum > coupled to a low RPM could signal an engine overload. For sudden > reductions in load, it might be handy to allow the throttle to close > faster than the opening rate. > It is a 180 HP Diesel driving a 40,000 watt generator. The rotating weight is massive. For those who question the mismatch, the engine will be at low RPM for efficiency. Diesel engines don't have vacuum, they control fuel flow according to the power needed and the intake air is unrestricted. Otherwise the compression will not be enough to ignite the fuel. > > Sensing the AC output should be the same as a low count encoder, but if > the output fails or the field gets turned off, this might be seen as the > engine slowing down and cause the throttle to open all the way. Here is > another place for a safeguard or a magnetic pickup might be more > reliable. > I agree. I am thinking of approximately 10000 pulses (teeth) per second on the generator shaft which is turning 30 RPS. I hope this will be fast enough to keep the PID error from wandering. Thanks Don > -- > Kirk Wallace > http://www.wallacecompany.com/machine_shop/ > http://www.wallacecompany.com/E45/index.html > California, USA > > > > ------------------------------------------------------------------------------ > The modern datacenter depends on network connectivity to access resources > and provide services. The best practices for maximizing a physical server's > connectivity to a physical network are well understood - see how these > rules translate into the virtual world? > http://p.sf.net/sfu/oracle-sfdevnlfb > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ The modern datacenter depends on network connectivity to access resources and provide services. The best practices for maximizing a physical server's connectivity to a physical network are well understood - see how these rules translate into the virtual world? http://p.sf.net/sfu/oracle-sfdevnlfb _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
