6 Apr
2013
6 Apr
'13
12:30 a.m.
On Apr 5, 2013, at 3:36 PM, Dave McGuire <mcguire at neurotica.com> wrote:
On 04/05/2013 06:02 PM, Tony Duell wrote:
I'm suggesting that they might be three-phase, as they are in many other
large VAXen. (I've never worked on the innards of an 11/780 myself) As
you're likely aware, in some VAXen the ONLY three-phase component(s) is/are
the blowers.
I just checked the field maintenance manual for the 11/780. I was correct in my
earlier statement in that 3-phase is supplied for load balancing. The power controller
is 3-phase but it splits out the individual phases. It splits the 3 phases into 4. Phase
1
has switched and unswitched outlets. Phases 2 & 3 are both switched. Blowers 1 &
3
are on switched Phase 3. Blower 2 is on unswitched Phase 1.
In more detail here are the connections (not just the blowers):
Phase1 Unswitched:
1. Blower #2
2. H7111 (T.O.D.)
3. PS #4 (MS780)
4. H7112 (memory battery backup)
Phase 1 Switched:
1. 11/03
2. RX01
Phase 2 Switched:
1. PS #3 (CPU)
2. PS #1 (FP780)
3. RX01 fan
4. A.F. Sensor Box
Phase 3 Switched:
1. PS #2 (CPU)
2. Blower #1
3. Blower #3
4. PS #5 (RH780)
BTW on 115v 60Hz systems, the power controller is an 866-D.
TTFN - Guy
Agreed. The one place I am going to start is with the
power supplies. I plan on running this on
single phase at least initially. I don't see anything in there that needs 3 phase.
The blowers?