Re: [CAD_CAM_EDM_DRO] gecko 320 filter capacitor values

That's 3.7HP. The thing is, traversing at a constant speed itself only has to overcome the friction of the system. The real load is in accelerating and slowing a heavy table at high rates. Geckodrive ALSO has an important white paper on that too!

If one were to accelerate a 15lb table from 0 ipm to 100 ipm in 0.5 sec, with X leadscrew/ballscrew/belt efficiency, the motor's peak power usage can be calculated. Software should limit the acceleration for you, to the value you specify. At least it does with steppers, I assume it'll do the same with servos.

I'm saying you may calculate out the highest possible acceleration rates you'd ask for and might find the current could be 10A peak, for example. Thus no reason to design for the 38A rate. Your transformer may not be able to put out 38A for even brief periods, anyways, not without dropping enough voltage to undermine your ripple criteria.

Danny

---- Denis Casserly <denisc1@...> wrote:

> HI Danny,
> it's 38Amps peak current, not steady state. I suppose it will only peak for
> short times when doing rapid traverse. Yes, it's connected to 60 cycle toroid,
> through a bridge.
> cheers,
> Denis
>
> On Wednesday 04 March 2009 17:20:06 Danny Miller wrote:
> > What type of power source are you hooking this up to? A 60Hz transformer?
> >
> > 38A is phenomenally high. I doubt this is actually going to be in you
> > design criteria, because it would be crazy high. Basically, you'd need
> > to first figure out the maximum load the servo would actually USE based
> > on the desired acceleration and table mass.
> >
> > Danny
> >
> > > -----Original Message-----
> > > From: CAD_CAM_EDM_DRO@yahoogroups.com
> > > [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of dcassyc1 Sent:
> > > Thursday, February 26, 2009 12:05 AM
> > > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > > Subject: [CAD_CAM_EDM_DRO] gecko 320 filter capacitor values
> > >
> > > Hi all,
> > > I'm looking for advice on sizing power supply filter capacitors for Gecko
> > > 320 servo drives, used to power 2 separate servo applications.
> > > First application is for 1 servo motor rated with these specs:
> > > terminal voltage: 72 VDC continuous current: 8.5A peak current: 38A.
> > > How large should the filter capacitor be? Would a 100VDC rating be
> > > sufficient for this 72 volt supply? How many MFD?
> > > Second application is for 2 motors with these ratings:
> > > terminal voltage 60 VDC continuous current 3.5A peak current 20A. Would a
> > > 75 VDC capacitor be sufficient for this 60 VDC supply? How many MFD?
> > > Is there a formula that is available to calculate the mfd value?
> > > Is there a recommended maximum ripple voltage?
> > > cheers,
> > > Denis
>
>
>
> ------------------------------------
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@..., timg@...
> Moderator: pentam@... indigo_red@... davemucha@... [Moderators]
> URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
> List Mom
> List Owner
>
> Yahoo! Groups Links
>
>
>