CAD CAM EDM DRO - Yahoo Group Archive

Re: Power supply

Posted by caudlet
on 2008-06-13 11:03:45 UTC
--- In CAD_CAM_EDM_DRO@yahoogroups.com, "David G. LeVine"
<dlevine144@...> wrote:
>
> Jon Elson wrote:
> > Jameco has some really cheap switching power supplies. This may
> > be at the upper range of the wattage they have. You could
> > probably get two 12 V 8 A supplies and put them in series. The
> > single-output supplies generally are fully floating, so can be
> > series-ed easily.
>
> Switching power supplies usually do not sink current well. Put a BIG
> computer grade electrolytic across the output to help absorb the spikes
> generated by switching.
>
> --
> David G. LeVine
> Nashua, NH 03060
>

Power supplies do not typically "sink" current. They have smaller LC
type filters on the outputs because they only have to filter the HF
switching. Most have pretty decent transient response times but a
moderate amount of external capacitance acts to lower the loop
response gain and provide a regulated output. Putting too much
capacitance in the output could cause the power supply to go into
current limiting on power up and refuse to turn on (sees the big ole
filter cap as a low impedance load). The current waveform of the PWM
to the motors is based on the primary PWM frequency and the inductance
of the motors.

For smaller loads (typical 3A motors times 3 or 4) we have used
switching power supplies with no external caps. Been running one in
production for over a year. Without an external output cap the
ability of the unit to reduce back EMF is diminished. Perhaps that
was the reference to "sinking" current.

Discussion Thread

pkranger63@y... 2001-11-23 18:04:55 UTC Power supply Bob Campbell 2001-11-23 18:20:33 UTC Re: [CAD_CAM_EDM_DRO] Power supply shymu@b... 2001-11-23 18:52:44 UTC Re: Power supply shymu@b... 2001-11-23 19:31:37 UTC Re: Power supply Bill Vance 2001-11-23 22:58:03 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply High Tech 2001-11-24 08:52:14 UTC RE: [CAD_CAM_EDM_DRO] Power supply Bill Vance 2002-04-19 11:42:57 UTC Power supply mariss92705 2002-04-19 12:31:28 UTC Re: Power supply workaholic_ro 2002-04-19 14:48:59 UTC Re: Power supply mariss92705 2002-04-19 19:42:33 UTC Re: Power supply Raymond Heckert 2002-06-23 13:34:15 UTC Re: [CAD_CAM_EDM_DRO] Power supply JanRwl@A... 2002-06-23 15:57:22 UTC Re: [CAD_CAM_EDM_DRO] Power supply krashking405 2006-05-28 16:26:37 UTC Power supply caudlet 2006-05-29 08:12:33 UTC Re: Power supply krashking405 2006-05-29 16:42:34 UTC Re: Power supply Abby Katt 2006-05-30 04:36:35 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply ballendo 2006-05-30 05:40:35 UTC Re: Power supply Graham Stabler 2006-05-30 07:25:37 UTC Re: Power supply Roy J. Tellason 2006-05-30 08:09:39 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply Roy J. Tellason 2006-05-30 08:16:57 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply Mina Aboul Saad 2006-06-24 04:11:52 UTC Power supply Lester Caine 2006-06-24 04:48:07 UTC Re: [CAD_CAM_EDM_DRO] Power supply Abby Katt 2006-06-24 05:02:00 UTC Re: [CAD_CAM_EDM_DRO] Power supply Peter Reilley 2006-06-24 05:22:03 UTC Re: [CAD_CAM_EDM_DRO] Power supply Larry Bush 2006-06-24 05:32:54 UTC Re: Power supply Tony Jeffree 2006-06-24 05:49:42 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply David Speck 2006-06-24 06:40:16 UTC Re: [CAD_CAM_EDM_DRO] Power supply Robert Renfro 2006-06-24 07:26:09 UTC Re: Power supply Robert Campbell 2006-06-24 07:26:41 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply Thea xxxxx 2006-06-24 07:26:56 UTC AW: [CAD_CAM_EDM_DRO] Power supply David Speck 2006-06-24 07:37:03 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply Peter Reilley 2006-06-24 07:58:12 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply David Speck 2006-06-24 08:47:08 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply Peter Reilley 2006-06-24 09:38:08 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply Stephen Wille Padnos 2006-06-24 09:47:18 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply turbulatordude 2006-06-24 10:28:46 UTC Re: Power supply Peter Reilley 2006-06-24 11:12:46 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply David Speck 2006-06-24 12:34:22 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply Peter Reilley 2006-06-24 13:44:46 UTC Re: [CAD_CAM_EDM_DRO] Re: Power supply Dave Halliday 2006-06-24 18:59:21 UTC RE: [CAD_CAM_EDM_DRO] Power supply Raymond Heckert 2006-06-25 18:12:16 UTC Re: [CAD_CAM_EDM_DRO] Power supply Jon Elson 2006-06-25 22:19:08 UTC Re: [CAD_CAM_EDM_DRO] Power supply Jack Mc Kie 2008-06-11 07:58:00 UTC Power supply JCullins 2008-06-11 10:22:56 UTC Re: [CAD_CAM_EDM_DRO] Power supply Jon Elson 2008-06-11 10:25:31 UTC Re: [CAD_CAM_EDM_DRO] Power supply David G. LeVine 2008-06-13 09:39:29 UTC Re: [CAD_CAM_EDM_DRO] Power supply caudlet 2008-06-13 11:03:45 UTC Re: Power supply