Switching power supplies and overcurrent protection
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From: Phil Allison on 4 Dec 2009 22:44 <oparr(a)hotmail.com> "Phil Allison" > >The output filter electros in SMPS will always supply fast, over ( rated) >current spikes. :Well, fast is a relative term, ** Sure is. You need to learn basic electronics terminology. : so let me put it this way... ** You need to lean to write clear English. Shame the pre-requisite for that is clear thinking. : I've found Meanwell shutdown and hiccup SPS types : to be unsuitable for my needs. ** Simple - don't use them. You already know what kind of PSU works . ...... Phil
From: oparr on 5 Dec 2009 02:38 >You already know what kind of PSU works . I think it suffices to say that the mean spirited and the wretched from down under are best avoided. On Dec 4, 10:44 pm, "Phil Allison" <phi...(a)tpg.com.au> wrote: >
From: Joerg on 5 Dec 2009 10:53 oparr(a)hotmail.com wrote: >> Depends on your application. If those spikes are "normal" in your >> scenario and not an indicator of doomsday being around the corner then >> constant current may be your ticket. > > App is low power DC servo CNC. Unregulated DC supplies are the norm > here but nowadays a SPS can be cheaper than the AC transformer alone. > DC motor current spikes are the norm and harmless to the motors. > Problem is the spikes trip SPS shutdown types and cause the servo > drive to trip on excess following error, due to lost voltage during > hiccups, with SPS hiccup types. > Then you need one with clean current limiting or hang a large capacitor onto it. But there is often a maximum allowed capacitance so I'd ask the manufacturer. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: whit3rd on 5 Dec 2009 14:29 On Dec 5, 7:53 am, Joerg <inva...(a)invalid.invalid> wrote: > op...(a)hotmail.com wrote: > > App is low power DC servo CNC. Unregulated DC supplies are the norm > > here but nowadays a SPS can be cheaper than the AC transformer alone. > > DC motor current spikes are the norm and harmless to the motors. > > Problem is the spikes trip SPS shutdown > Then you need one with clean current limiting or hang a large capacitor > onto it. Brushes in DC motors might short intermittently, and the ripple current (1) doesn't drive the motor (isn't required), and (2) might overstress a capacitor. A series choke is an easier solution than big capacitor, in this case.
From: Jamie on 5 Dec 2009 14:48
Joerg wrote: > oparr(a)hotmail.com wrote: > >>> Depends on your application. If those spikes are "normal" in your >>> scenario and not an indicator of doomsday being around the corner then >>> constant current may be your ticket. >> >> >> App is low power DC servo CNC. Unregulated DC supplies are the norm >> here but nowadays a SPS can be cheaper than the AC transformer alone. >> DC motor current spikes are the norm and harmless to the motors. >> Problem is the spikes trip SPS shutdown types and cause the servo >> drive to trip on excess following error, due to lost voltage during >> hiccups, with SPS hiccup types. >> > > Then you need one with clean current limiting or hang a large capacitor > onto it. But there is often a maximum allowed capacitance so I'd ask the > manufacturer. > He just needs a choke and load R .. common problem. |