26 Jul
2018
26 Jul
'18
9:02 a.m.
On 07/26/2018 09:54 AM, Anders Nelson via cctalk wrote:
To get that power, did they have to use a rotary
convertor from 60Hz
3-phase to get 400Hz?
IBM mainframes in the late 1950's early 1960's (707x and
709x series) used motor generators to generate 400 Hz
3-phase power, which was distributed to all the major
components.
For the 360, they came up with a solid state version, it ran
the CPU, memory and such on 2500 Hz single-phase power,
using a "converter-inverter". It rectified and filtered the
3-phase 50- or 60-Hz input to DC, and then used ultra-fast
SCRs to invert it. But, the energy stored in the filter
caps in that was way smaller than the rotational energy in a
motor generator set. So, the 360 was susceptible to power
glitches and dips. For the 370, they went back to a
motor-generator set actually INSIDE the CPU cabinet to
produce 415 Hz 3-phase power. Larger systems often had a
UPS with electronic inverters in them.
Jon