Tom:  Yes, this is indeed a tempo control, or "moderator" as it is
often labeled, such as on a Mira or Regina disc box.

The wire should be able to be adjusted so that it can change the speed
of rotation of the governor without completely stopping it or impinging
on the fan blades.  It may take some trial and error, but it was
designed to do this.  Perhaps a previous owner (or restorer) was unable
to make it right and so they gave up and bent it out of the way.

With this tempo moderator, if a dance tune is playing too fast, the
tempo can be adjusted so that the dancers can keep up with the music.
Or if a hymn was played, the singers could keep up.  A nice feature to
have!

Musically yours,
Bill Wineburgh
http://antiquemusicbox.110mb.com/