If you only need one, try some second hand shops for an old recodr
player. One with a synchronous motor.
If you apply DC to the coil it will act as an eddy current brake. I
don't know just how much current you'll need but you will need ALOT
less than 120 volts to do it. That much DC voltage will cook it.
Actually pretty much any induction motor can work as a brake, if you put DC
through the windings. Of course all of the mechanical power (and the
electrical power from the DC supply) will end up as heat inside the motor,
so be careful not to cook it. Most of the mechanical power will end up
heating the rotor. If you are getting rid of a lot of power and the RPMs
are too low for the motor's own fan to be effective then consider adding a
blower to force air through the motor.