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 <paulkon...@comcast.net> wrote: > > > > On Jul 15, 2021, at 4:19 PM, Michael Thompson via cctech < > cctech@classiccmp.org> wrote: > > > >> > >> From: Paul Koning <paulkon...@comcast.net> > >> To: Chris Zach <c...@alembic.crystel.com>, "cct...@classiccmp.org" > >> <cct...@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 > is > >> single phase, balanced.) > >> > >> paul > >> > > > > 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 > ? > > paul > > -- Michael Thompson
