On 11/06/2016 09:18 AM, et...@757.org wrote: >> But smaller than the Crays of the era. If it doesn't run on 400Hz, >> it's a 'mini' supercomputer. > > Hmmm I knew the earlier Crays often had motor generator setups and > such but I thoght that was just for power filtering and maybe > flywheels for ups setups. Didn't know they were 400hz! Odd!
Not at all--that goes back at least to the 1960s. Consider the CDC mainframes--MG sets providing 3-phase 400Hz power to variac-regulated 3-phase fullwave rectifier setups. The ripple frequency is 2400Hz and has a very high DC component. This is a very sensible arrangement, as the power supplies need not be tailored to a specific line voltage or frequency. I'm somewhat surprised that no one talks much about cooling systems on supercomputers, be it forced air or liquid nitrogen. Both Cray and CDC spent a fair amount of time and money on getting cooling to their big machines. How about cooling towers for the chilled water supply? --Chuck
