Best I can find is http://www.nidec-servo.com/jp/digital/pdf/DME34.pdf
In japanese, doesn't have exact part, there is DME34B50G, but not DME34BE50G. Note there are misprints (DMN for DME) and that even that part number covers a range of different gearings and I can't figure out if voltage is given... But should be the same basic power / design?