An eddy current clutch is simply a device that passes load torque through to the motor
without modification while reducing the motor speed to the load by an adjustable amount, typically 95% down to about 20%.
Regarding speed, note that the max clutch output speed is never equal to the motor speed.
The clutch, when fully locked up at max speed, still has between 3 and 5% slip so figure
that into your max speed calculations on the new system.