RK05 spindle pulleys - trade 50Hz vs 60Hz?

[Mattis Lind]

2018-07-26 6:21 GMT+02:00 Paul Anderson via cctalk <cctalk at classiccmp.org>:

> 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.
>

You need to move the motor to a new position in the RK05. The drive is
already prepared for all this. It is just the pulley, moving the motor and
the 220VAC jumper that is needed.

/Mattis


>
> 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
> >
>