8 Jun
2013
8 Jun
'13
12:36 a.m.
On 08/06/2013 02:21, Jim Stephens wrote:
And when you
do the 0-200 ips forward read on say a 3420 or 5, it goes
into motion in a real hurry. With an 3803, the bottom 1/3 of the
cabinet is a huge transformer, for instance. There are also pretty
serious blowers for vacuum column drives.
On 6/7/2013 4:37 PM, Ian King wrote:
> On 6/7/13 3:16 PM, "Dave McGuire" <mcguire at neurotica.com> wrote:
>
>> On 06/07/2013 04:41 PM, Tony Duell wrote:
>>> That's serious power -- 10's of kW. What on earth does it use it all
>>> for?
>>> How can a tape drive take 40A on 3 phases? The motors can't be that
>>> big,
>>> surely?
They were HUGE in the early drives. I think its more re-wind speed. Time
spent re-winding is time the computer is idle. I remember blowing an
auxiliary generator with tape drive rewinds.
You could hear it slow as the drives went to rewind. When it stalled
there was a "bang" and a puff of smoke and many odd words from our small
Scottish engineer who I am sure was called "Jim"
A reel of 1/2" tape has serious angular momentum.....
I would guess that it has something to do with
needing to start and
stop the spindle motors very quickly.
It's also that the power is distributed to multiple slave drives from
the
controller/primary drive cabinet. So all the power for up to (ISTR)
five
nine-track vacuum-column drives is coming through one straw. -- Ian