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@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 >