Victor was founded in 1893 and was a major early supplier of x-ray equipment and other electrotheraputic devices.  It was incorporated as the Victor Electric Corporation in 1916, the Victor X-Ray Corporation in 1920 as part of General Electric, and was eventually totally absorbed by General Electric in 1926, and its lineage can be traced through to the present time as a foundation of the GE Medical Systems division.  

There was no connection with the Victor Talking Machine Company (later to become RCA-Victor), or the Victor Animatograph Corporation of Davenport, IA, a manufacturer of movie projectors.

A motor-generator, simply, is a motor and a generator that were combined into the same unit, with a common shaft.  The motor section operated on 110 volts DC, and the generator provided something in the neighborhood of 12 volts DC.  A variable resistance (operated by the lever control in the base) controlled the speed and, hence, the output voltage.  A rotary on-off switch was also mounted on the base.  It stands about 10 inches high, on a 6 by 7 inch cast iron base, and weighs about 24 lbs.  Most of the metal parts were originally nickel plated, and the base and frame were decorated with gold pinstriping.  The platform on top is marble.

While no information has been found to conclusively identify the purpose of this unit, it is quite likely that it was used to provide power to x-ray or other apparatus that was originally designed to operate from batteries.  In those areas that were only supplied with DC power, a motor-generator such as this would have been the most efficient way of dropping the line voltage.