On 12/11/2013 6:02 PM, Leonardo Marsaglia wrote: > 2013/12/11 Dave Cole <linuxcncro...@gmail.com> > >> If it meets your needs then you have succeeded. :-) >> >> I have put AC servos on Induction Hardening machines before. The >> machine you are using may be similar to the one I automated. The >> shaft/camshaft moves vertically through an energized induction coil and >> is sprayed with water to create harden the surface. I put a high dollar >> Parker servo on one years ago and the drive went crazy when the >> induction coils were energized. We tried everything and ended up >> putting in a much cheaper AC servo drive and the problems went away. >> :-) The induction coils induce voltage into everything that is near >> the them, including cables, motors, etc. The machine frame "ground" >> varies in potential along the machine frame. >> >> Well in this machine the camshaft is stationary and turns on its own > center to get a homogeneous heating. The coil and the shower move all the > way to make the treatment. The carriage is heavy and also it's suspended > because the ways are on one side, so this is what makes this mechanism more > noisy and rough. I mean it's not a bad machine, but it's heavy and bulky > for the job. I hope I don't have that problem of the induced voltage on the > VFD, we'll see that in a few days when we turn on the heater. > > >> If you have a similar machine, then .3-.4 mm of error is quite acceptable. >> > Yes indeed, I'm more than happy with this because I was affraid that tuning > this could consume a lot of time but I can start to work now and improve > the tuning everytime the machine is not working. The most important things > are to reduce the vibration when the carriage moves up, and also find a way > to reduce my following error when the joint accelerates because that's when > I got the most critical following error, so If I set low values I got the > problem, but if I set it high the machine works fine and I got those .3 or > .4 mm of error wich is quite good. Remember that this machine worked with > switches like limit switches and it had a big plate with the wedges (I > don't know if wedges is ok). Anyway this was ok for the time but now I need > to change the programs often and it's an obsolet sytem. > > Also, if you see the original motors for the positioning system you'll be > crazy. The machine had a DC motor with a reductor for the precise movements > when the part was being heated. And that motor also was feeded by a DC > generator that was powered by another AC motor. This is only for the > precise movements. When the part was finished, the coil returned to the > home position by means of an AC motor. The machine switched between the DC > motor and the AC motor using a electromagnetic clutch. That was a hell of > KW wasted for a simple process, even for that year (1975) they could have > used DC servos. Anyway, that's all gone now and I'm glad LinuxCNC is again > making me happy with its result :). > >
It sounds like you are greatly simplifying the machine. An MG set (motor generator set) is a very old technology to create DC power. That was probably obsolete when it was installed. When the Parker Servo malfunctioned it was very obvious. It had a digital display on the front to show status and it would go blank when the induction power was applied to the heating coils. It was quite literally "lights out". I thought that I had lost power to the drive due a wiring error or blow fuse. Dave ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. Most IT organizations don't have a clear picture of how application performance affects their revenue. With AppDynamics, you get 100% visibility into your Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
