Most old pre-solid-state aircraft electronics also used 415 Hz because transformers are much lighter at higher frequency.
Barry Merrill, EI/W5GN (where I use 14MHZ!) Herbert W. “Barry” Merrill, PhD President-Programmer MXG Software Merrill Consultants 10717 Cromwell Drive Dallas, TX 75229-5112 [email protected] Fax: 214 350 3694 – Still works, received as email Tel: 214 351 1966 – Unreliable, please use email www.mxg.com HomePage: FAQ answers most questions [email protected] License Forms, Invoice, Payment, ftp information [email protected] Technical Issues MXG-L FREE ListServer http://www.mxg.com/mxg-l_listserver/ -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of William Donzelli Sent: Wednesday, July 29, 2015 12:57 PM To: [email protected] Subject: Re: 1403 at 60Hz > As I understood it at the time, larger S/360 and S/370 also used > motor-generator power supplies, though I don't know the output > frequency. The higher frequency means less filtering. Generally 415 Hz. Why this odd number is beyond me. The Hitachi clones also used 415 Hz. > But yes, you can run a CDC machine off an electronic converter. Most CDC Cybers are indeed 400 Hz machines, but a few were made with a 60 Hz option. Last week I drove to Texas to get a "small" "departmental" Cyber 932 - they were all (or nearly all?) 60 Hz models. -- Will ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
