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From: oparr on 4 Dec 2009 21:46
I see three types of overcurrent proctection in SPSs these days -
Shutdown, hiccup mode and constant current limiting. Unlike with
shutdown and hiccup types, is it correct to assume that voltage is
never disconnected from the load, during an overcurrent condition, for
CC limiting types? And if so, wouldn't this be the best type of SPS to
use in the event of fast overcurrent spikes?
From: Joerg on 4 Dec 2009 21:56
oparr(a)hotmail.com wrote:
> I see three types of overcurrent proctection in SPSs these days -
> Shutdown, hiccup mode and constant current limiting. Unlike with
> shutdown and hiccup types, is it correct to assume that voltage is
> never disconnected from the load, during an overcurrent condition, for
> CC limiting types? And if so, wouldn't this be the best type of SPS to
> use in the event of fast overcurrent spikes?


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. I use it a lot, for example in gear
that can occasionally arc and where that is considered ok. But there is
usually some sensing included that puts a lid on it when the frequency
of spikes gets to be too much.

If stuff could be overstressed consider slight foldback.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
From: Phil Allison on 4 Dec 2009 22:09

<oparr(a)hotmail.com>
>
>I see three types of overcurrent proctection in SPSs these days -
> Shutdown, hiccup mode and constant current limiting. Unlike with
> shutdown and hiccup types, is it correct to assume that voltage is
> never disconnected from the load, during an overcurrent condition, for
> CC limiting types? And if so, wouldn't this be the best type of SPS to
> use in the event of fast overcurrent spikes?


** The output filter electros in SMPS will always supply fast, over ( rated)
current spikes.

IME - only linear PSU have instantaneous acting current limiting.


...... Phil


From: oparr on 4 Dec 2009 22:26
> 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.

On Dec 4, 9:56 pm, Joerg <inva...(a)invalid.invalid> wrote:
>
From: oparr on 4 Dec 2009 22:39
>The output filter electros in SMPS will always supply fast, over ( rated)
>current spikes.

Well, fast is a relative term, so let me put it this way....I've found
Meanwell shutdown and hiccup SPS types to be unsuitable for my needs.

On Dec 4, 10:09 pm, "Phil Allison" <phi...(a)tpg.com.au> wrote:
>
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