[Info-vax] OT: the Daily WTF for today is a VAX/VMS story

[Johnny Billquist]

On 2016-02-15 00:02, William Pechter wrote:
> In article <n9qlta$2rv$1 at Iltempo.Update.UU.SE>,
> Johnny Billquist  <bqt at softjar.se> wrote:
>> On 2016-02-14 19:53, Steven Schweda wrote:
>>>> [...] Anyone with half a brain [...] There is no spinup
>>>> time. You go from standstill to full speed immediately,
>>>> always. [...]
>>>
>>>      Perhaps the other half-brain is the one which paid some
>>> attention in its physics class.  Instantaneous anything can
>>> be tough to obtain with finite resources.  Or is your claim
>>> that the rotor here has no mass (moment of inertia, actually,
>>> so perhaps it's the radius which is zero, not the mass).
>>
>> Which is why when I played with 3-phase AC motors, they were firmly
>> attached to a bench, and the bench had a tendency to jump when power was
>> applied. And we're talking about a big bench...
>>
>> But yes, "instantaneous" is a strong word here. The inertia makes it
>> impossible to really be instantaneous. But the acceleration is violent,
>> and the physical forces are large.
>>
>> An RP06 takes about 30-45 seconds to spin up... It is no where near the
>> way you can get an AC motor to work.
>>
>> 	Johnny
>>
>> --
>> Johnny Billquist                  || "I'm on a bus
>>                                    ||  on a psychedelic trip
>> email: bqt at softjar.se             ||  Reading murder books
>> pdp is alive!                     ||  tryin' to stay hip" - B. Idol
>
>
> In 3/8/09 in an article you posted in google groups -- wouldn't two phase mean
> an AC motor...
>
> just a poor old ex-DEC Field Engineer here... there's no way the RP06
> used a DC motor...

I know the drive uses two phases. And it's connected either in a wye or 
delta setup, depending on what feed you have. That would not necessarily 
mean the spindle motor is an AC motor. But since you think it is, and I 
believe you have worked more of these drives than I have, I'll accept 
that I'm wrong.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol