how fast were drum memories?
mloewen at cpumagic.scol.pa.us
Fri May 11 06:49:57 CDT 2018
The manual says 125A per phase (3-phase, 208V) starting current.
I remember spin-down as 20 minutes, but that was a long time ago. :-)
On Fri, 11 May 2018, Paul Anderson wrote:
> The good old days...
> I recall the Q-7 drums would take about 15 minutes to come to a stop when
> turned off, and would power up in seven seconds or less. Surge current was
> around 115 amps?
> On Thu, May 10, 2018 at 3:46 PM, Mike Loewen via cctalk <
> cctalk at classiccmp.org> wrote:
>> On Thu, 10 May 2018, Al Kossow via cctalk wrote:
>> On 5/10/18 10:37 AM, Al Kossow via cctalk wrote:
>>>> On 5/10/18 9:29 AM, Paul Koning via cctalk wrote:
>>>> One that comes to mind is the DEC RS04. It spins at roughly 3600 rpm (a
>>>>> hair less, so obviously a 2 pole induction motor running off 3-phase 60 Hz
>>>> Vermont Research drums (model 1175B) spun at 3450 rpm 3ph 220v, The HP
>>>> 2773 on the 2000A TSB was from VR so I expect RPM
>>>> would be similar for most drums of similar diameter.
>>> Just checked, and the LGP-30 and RPC-4000 drums are both listed as 3600
>> The drums on the SAGE system (12 on each side), are listed as follows:
>> Diameter: 10.7"
>> Width: 12.5"
>> Weight: 105 lbs (cylinder, only), 450 lbs for entire drum assembly
>> Speed: 2914 rpm
>> Heads: Up to 12 R/W bars, with up to 40 heads on each bar, 1
>> erase bar
>> 6 pairs, one for Compuuter-to-Drum (CD), one for
>> Other-than-computer-to-Drum (OD)
>> Head spacing 0.3" apart on each bar
>> Drum Layout: 2048 registers on 33 channels (tracks), 6 fields
>> Channel spacing is 0.050"
>> Access Time: Maximum 20ms, average 10ms
>> Write Current: 110ma
>> The R/W bars are arranged in pairs (CD and OD) so that I/O devices can
>> access the drum independently of the computer.
>> More than you ever wanted to know about SAGE drums (thanks, Al!):
>> Here's one of the earlier style R/W heads:
>> Mike Loewen mloewen at cpumagic.scol.pa.us
>> Old Technology http://q7.neurotica.com/Oldtech/
Mike Loewen mloewen at cpumagic.scol.pa.us
Old Technology http://q7.neurotica.com/Oldtech/
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