🚀 go-pugleaf

In article <1600@ocpt.ccur.com>, pechter@ocpt.ccur.com (Bill Pechter) writes:
> In article <1992Aug26.095459.1@cc.curtin.edu.au> zrepachol@cc.curtin.edu.au (Paul Repacholi) writes:
>>> 
>>> All RP drives are 3 phase, as is the RM05. All others are single I'm reasonably
>>
>>The CDC 9766 is 3 Phase. In all disks I have seen, the motors are 3 phase, star
>>or delta conected, depending on local voltage ect, and the electronics are
>>conected from one phase to neutral. 
> 
> Sorry, the CDC9766 is a two phase drive.  Two hots only.  The motor
> on the RP04 was the only one I know that was three phase.
Two phases at 180deg or at 120 deg? The .AU power is 240 nominal from each
phase to neutral. The phases are at 120deg, hence 440v from phase to phase.
Neutral is tied to earth at the meterbox BTW, so the phases are resonably
symetric to earth. 
I understood the US two phase system was two 110v phases at 180deg, 220v phase
to phase, and in some places 208v phase to phase 120deg by local motor-altenator.
I have seen 'tricks' to run 3 ph motors off 1 or 2 phases, most having problems
at start-up. A 3 ph motor will run quite happily with only two phases connected,
but may not be able to deliver full power, or may be easier to stall.

> 
> I watched one spin backwards and bang the brushes against the outer wall
> at NJ Bell during an 11/70 reinstallation during my DEC Field Circus
> days.
> 
> The RP05/6 and RM series used two phases and you could balance load
> out quite easily by switching them in the plugs.
> 

I think we are crossing terminology some-where in this. Could some-one 
conversant with both systems explain.

~Paul