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

[Johnny Billquist]

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