--- In "geoffveale" <> wrote:
>
> I have not tried your combination, but I did build a system that had a
> Tri-M MZ104 (700mA at 5V) and a Maxtor HDD that had a spec requirement
> of 475mA at 5V. My supply was via a 10W DC-DC converter that should
> have given 2000mA at 5V. With this setup sometimes the drive would
> start and sometimes it would not start. From this experience I would
> say that a bare minimum requirement would be 3 x the rating of the
> HDD. So in your case 1500mA should be sufficient to get your HDD
> starting reliably, but if possible give it a little more to be
> absolutely sure.
>
Google for "locked rotor load". You'd be surprised how much a motor
can draw when starting up under locked rotor conditions.
For a single phase AC motor, I've seen figures as high as 10x running
loads. I have no idea what comparable loads are for the types of DC
motors used in hard drives but I would guess they're substantial
compared to the continuous load requirement.
I would also guess that HD motors are sized just barely big enough to
spin the drive while running since they don't have to accelerate or
deal with varying loads. So when they start, they're effectively
under locked rotor conditions.
--Yan
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/ts-7000/join
(Yahoo! ID required)
<*> To change settings via email:
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|