dougm@madnix.UUCP (Doug McIntyre) (11/18/90)
I want to move the hard drive out of my Unix PC to reduce the
drain on the poor little power supply and have a second one as well.
How much power can an average hard drive draw? Would a 60W supply
be enough for a couple drives or do I have to go a little bigger?
--
UUCP: {harvard|rutgers|ucbvax}!uwvax!astroatc!nicmad!madnix!dougm
{decvax|att}!mvadh@cbnews.att.com (andrew.d.hay) (11/19/90)
In article <1630@madnix.UUCP>, dougm@madnix.UUCP (Doug McIntyre) writes: > > I want to move the hard drive out of my Unix PC to reduce the > drain on the poor little power supply and have a second one as well. > How much power can an average hard drive draw? Would a 60W supply > be enough for a couple drives or do I have to go a little bigger? yes; the most i've seen for any hd is ~36w. most are *well* under this (18w for my 40M hh, *9w* for 80M 3.5"). the 67M 3b1 drives were 28w. -- Andrew Hay +------------------------------------------------------+ Ragged Individualist | You just have _N_O idea! It's the difference | AT&T-BL Ward Hill MA | between _S_H_O_O_T_I_N_G a bullet and _T_H_R_O_W_I_N_G it! | a.d.hay@att.com +------------------------------------------------------+
thad@cup.portal.com (Thad P Floryan) (11/21/90)
dougm@madnix.UUCP (Doug McIntyre) in <1630@madnix.UUCP> writes: I want to move the hard drive out of my Unix PC to reduce the drain on the poor little power supply and have a second one as well. How much power can an average hard drive draw? Would a 60W supply be enough for a couple drives or do I have to go a little bigger? and is answered by: mvadh@cbnews.att.com (andrew.d.hay) in <1990Nov19.134747.26946@cbnews.att.com> who writes: yes; the most i've seen for any hd is ~36w. most are *well* under this (18w for my 40M hh, *9w* for 80M 3.5"). the 67M 3b1 drives were 28w. Ahem. Sorry for my delayed reply; past 3 days been working 25 hrs/day at the office, then when I arrive home PORTAL is dead and nada. In any event ... As to whether a 60W supply will function CORRECTLY, it depends on the TYPE of hard drive. For example, a Maxtor drive (any of XT2190, XT3380, XT4380, XT8760, etc.) is specified as approx. 27.5W. But just TRY and get one of those suckers started using your common, everyday 45W or 60W or even 80W supply; heh heh. The startup surge requirements for said drives is so great that those "common" supplies will NOT work and will only serve to cog the drive (no damage will occur if you realize what's happening and shut everything down). What IS required for such drives are the "special" power supplies manufactured by companies such as Astec and a few others, which are designed to supply the humongous amount of startup current for a short time even though the supply itself may be rated for only, say, 45W. Believe me, I run Maxtor drives myself on MANY systems, and just two months ago replaced the DEC RA81 and RA82 floor-standing drives on my VAXes with in-the-cabinet Maxtor XT8760E drives; what I used for the VAXes were some surplused, but new, IBM AT chassis, gutted, for their mongo power supplies and strong cabinets to hold the drives ... this whole combination was able to be mounted in the VAXes' racks (I'm NOT talking about desktop systems here :-) If you have the OEM manual for Maxtor drives, you'll note that the drives can be programmed for startup delays; this means that although, say, an 80W supply may be able to operate the drives once spinning, it may be inadequate to START the drives spinning, so a staged turn-on sequence is de rigeur. "Most" drives available to the consumer don't have the startup "problem" typified by industrial quality HDs, and the only reason I've rambled on here is to alert you to the possiblity that the power supply you get "may" not be adequate for your (unspecified) HD. For the record, the 3B1 power supply IS able to start and sustain a Maxtor mounted in the system cabinet; I have NOT tried a 7300 power supply that way (but that's moot since the mongo Maxtor won't fit in a 7300 cabinet! :-) Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]
bdb@becker.UUCP (Bruce D. Becker) (11/29/90)
In article <36101@cup.portal.com> thad@cup.portal.com (Thad P Floryan) writes: |[...] |For the record, the 3B1 power supply IS able to start and sustain a Maxtor |mounted in the system cabinet; I have NOT tried a 7300 power supply that way |(but that's moot since the mongo Maxtor won't fit in a 7300 cabinet! :-) I've been running a Maxtor 2190 and a Maxtor 1105 from a 3B1 power supply for many months without a problem. The system also has a combo card, loaded with memory, so the power supply is getting a big workout 8^)... -- ,u, Bruce Becker Toronto, Ontario a /i/ Internet: bdb@becker.UUCP, bruce@gpu.utcs.toronto.edu `\o\-e UUCP: ...!uunet!mnetor!becker!bdb _< /_ "I still have my phil-os-o-phy" - Meredith Monk