The power cord is three-phase, and actually daisy-chains to a second and
third drive. The phases on the AC output connector are rotated to balance
the load on all three phases when three drives are daisy-chained. If you
look at the power wiring diagram on page 3-120 of the Memorex 677-01 manual
you will see only two of the phases going to the power transformer.
On Thu, Jul 15, 2021 at 4:22 PM Paul Koning <paulkoning at comcast.net> wrote:
On Jul 15, 2021, at 4:19 PM, Michael Thompson via
cctech at classiccmp.org> wrote:
> From: Paul Koning <paulkoning at comcast.net>
> To: Chris Zach <cz at alembic.crystel.com>, "cctalk at
> <cctalk at classiccmp.org>
> Subject: Re: Looking for VAX6000 items
> A number of the large disk drives use 3 phase motors; RP04/5/6 are
> examples as well.
> Three phase motors won't run on single phase power without help from run
> capacitors. (There is no such thing as "two phase power" -- 220 volts
The RP06 uses 220VAC single phase motors for the spindle and blower.
Interesting. I distinctly remember a disk drive installation manual that
warned about phase order. Perhaps that was for the RP04 and not the RP05/6