25 Jul
2018
25 Jul
'18
9:21 p.m.
I can't find my IPB, but the maintenance manual shows there were both 50
and 60 hz versions made.
I think I've shipped them overseas, but never modified them. I did ship a
lot of RX02 drives overseas, and to properly convert them the pulleys,
belts, and wiring harness had to be swapped. We were always on the lookout
for parts. I still have a few different wiring harnesses around here
somewhere.
BA11-K conversions were also common. I still have interesting stories and
parts about them.
What gets me with the RK05 is how you can swap pulleys without swapping
belts. A few products had pulleys with two grooves, one for 50, the other
for 60. But you still needed a different belt.
Paul
On Wed, Jul 25, 2018 at 10:32 PM, Tony Duell via cctalk <
cctalk at classiccmp.org> wrote:
There are,
however, DEC products other than the RK05 which had different
transformers for 50 Hz and 60 Hz. For example, the H771 power supply used
in the RX01 and RX02. There were three H771 models, The H771A for 90-132
VAC 60 Hz, The H771C for 90-132 VAC 50 Hz, and the H771D for 180-264 VAC
50
Hz. The H771A uses a transformer rated for 60 Hz.
The H771C and H771D
both
use the same 50 Hz rated transformer, with
different wiring. The H771C
and
H771D also require one of two different wiring
harnesses to cover the
entire mains voltage range, e.g., 90-120 VAC vs 100-132 VAC for the
H771C,
or twice those voltages for the H771D.
IIRC that's a ferroresonant transformer (with a capacitor to resonate one
of the
windings to a harmonic of the power line frequency), so it's not
surprising it has
to be changed for 50Hz or 60Hz input.
-tony