how fast were drum memories?

[Paul Berger]

On 2018-05-10 4:01 PM, 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 power).
>> 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 rpm
>
>
The 4" drum in a IBM 650 is said to have rotated at 12,500 RPM.