> ------------------------------ > > Message: 7 > Date: Sat, 5 Apr 2008 21:57:11 -0700 > From: Dave Engvall <[EMAIL PROTECTED]> > Subject: Re: [Emc-users] SCR amplifier > To: "Enhanced Machine Controller (EMC)" > <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > > Hi Stuart, > OUCH! Those sound like a larger version of the Fijitsu-Fanuc amps I > pulled off the Mazak. > Rather slow by todays standards and not PWM so more heat. > If that is really 33 amps average and not peak then those are big amps. > I used Servo Dynamics 1525's on the Mazak but then they only have to > move a couple thou Kg. These > SD's were also used in the Mazak conversion at Galesburg (Cardinal > Engineering) ... see emc wiki. > They are 15 amps average and 25 A peak but will go up to 165 V which > provides a lot of power if one dares > drive their servo's with that kind of voltage. The SD's roll off at > about 2KHz, a bit faster than 3 phase SCR's. ;-) > I don't think SD makes anything larger in a non-custom amp. You might > ask tho. > > http://www.servodynamics.com/ > > If you are really brave you can always redesign the front end of the > Getty's with modern op-amps. > You will still be stuck with the old freq. response what ever you do. > > I hope someone else has better and cheaper ideas. > > HTH > > Dave > > > > ---------------------------------------------------------------------- > > --- > > This SF.net email is sponsored by the 2008 JavaOne(SM) Conference > > Register now and save $200. Hurry, offer ends at 11:59 p.m., > > Monday, April 7! Use priority code J8TLD2. > > http://ad.doubleclick.net/clk;198757673;13503038;p?http:// > > java.sun.com/javaone > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > ------------------------------ > > Message: 8 > Date: Sun, 06 Apr 2008 01:01:37 -0600 > From: Jon Elson <[EMAIL PROTECTED]> > Subject: Re: [Emc-users] SCR amplifier > To: "Enhanced Machine Controller (EMC)" > <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=us-ascii; format=flowed > > Stuart Stevenson wrote: > > Gentlemen, > > The servo amps on my cinci are GETTYS Model N350/N135 33 amp. > > These each have a few edge connected boards inserted on them for > > different functions. > > These are OLD analog boards. I am sure each component board could > > use a good tuning. As this is not feasible (AFAIK), I am researching > > how to remove the analog boards. I want to dumb down the amplifier and > > use the tuning in EMC to control everything. > > These have some heavy duty SCR's and heat sinks. Can anyone direct > > me to documentation or a project I could use to modify these amps? > > Stripping the board and using discrete components is an option. > > Throwing them away and purchasing new amps is possible but I like > > the idea of reusing some of the components. > > Nothing is off the table. > > Suggestions, comments welcome. > > Of course, I am looking for cheaper - faster - better. :) > Well, I don't know how well these will perform. The Fanuc A06B > series of phase-control servo amps ran off 3-phase power, so > they had 360 conduction pulses a second possible. If the Gettys > amps run off single-phase, they have only 120 possible > conduction pulses, which cuts severely into bandwidth. I'd > expect they have a real bandwidth of 10 Hz or so. Fine for > GE550 or A-B 7320 controls, but not much newer. You might run > into some serious tuning compromises with such low bandwidth in > the servo amp. Not much sense of EMC feeding 1000 new velocity > settings a second to an amp with 1% that much bandwidth. > > Without drawings of the amps, it could be a real headache to > refit them for a different command scheme. Somewhere in there > there is a one-shot circuit, probably using unijunction > transistors, that controls the phase angle of SCR firing from > the output of the current-loop error amp. That would most > likely be a discrete op-amp, but maybe it is one of the first > chip op-amps. > > Jon > > >
Gentlemen, Thanks - Dave and Jon - just the info I was looking for. It looks as if new amps will be cheaper-faster-better. Jon, is it possible to parallel two of your amps to double their capacity? thanks Stuart ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Register now and save $200. Hurry, offer ends at 11:59 p.m., Monday, April 7! Use priority code J8TLD2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
