Water cooled
> Am 13.10.2024 um 11:15 schrieb ben via cctalk <cctalk@classiccmp.org>: > > On 2024-10-12 7:40 p.m., Jon Elson via cctalk wrote: >>> On 10/12/24 20:07, Jon Elson via cctalk wrote: >>> On 10/12/24 16:25, Wayne S via cctalk wrote: >>>> Didn’t all the IBM mainframes use 400hz? Maybe ask the IBMers how they got >>>> 400hz. >>>> Also, can the local power company supply it? >>>> >> Oh, the IBM 7090 series had a 400 Hz motor generator. The mid-range IBM >> 360's (360/50 and 360/65) has "converter-inverters". There was a star >> rectifier that took in 208 V 3-phase and converted it to DC with an >> inductor-input filter at about 300 V DC. This was then fed to an >> inductor-input resonant inverter with fast SCRs at 2.5 KHz. All the power >> supplies for logic, memory, etc. ran off 120 V single-phase 2.5 KHz power. >> This kept the transformers and filter caps and inductors very small. The >> inverter SCRs were commutated by two smaller SCRs that momentarily shorted >> the main SCRs through oil-paper caps. >> The problem with this system is it didn't offer much ride-through capability >> if you had crummy power quality. >> Jon > What did they use for air conditioning? > > >
