IIRC 400 Hz is(was) widely used on aircraft. The reason was smaller, lighter components were a must for aircraft. The radios and radars of the day all used very high voltages and gulped a lot of power. Large transformers were common.
Given the availability of 400 Hz components, it baffled me why IBM would select 415. But, then, at the time, IBM was (in)famous for being incompatible. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Tom Marchant Sent: Friday, January 11, 2008 8:08 AM To: [email protected] Subject: Re: SEMI off topic On Thu, 10 Jan 2008 21:32:31 -0600, Paul Gilmartin wrote: >I was accustomed, decades ago, to hearing "400 Hz." Was it always >415 Hz., subject to verbal shorthand? Yes. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html NOTICE: This electronic mail message and any files transmitted with it are intended exclusively for the individual or entity to which it is addressed. The message, together with any attachment, may contain confidential and/or privileged information. Any unauthorized review, use, printing, saving, copying, disclosure or distribution is strictly prohibited. If you have received this message in error, please immediately advise the sender by reply email and delete all copies. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
