Add more speed to driven tools.

I have successfully changed the range of speed on the driven tools on my QT10ATC from 0-1500 to 0-2500 by changing size of the pulleys and parameters.
But thinking of a different way of doing it on my Multiplex 620 so I dont loose torque.
Both my ST30ATC and MP620 hast the same FR-A500 driving the motor that at least looks the same, they also have the same pulleys but my ST30ATC has 0-3000rpm and my MP620 only has 1500rpm.
The different is a parameter on the FR-A500 that is setting the maximum frequency that is set double on the ST30ATC (I think it was set to 60Hz on MP620 and 120Hz on ST30ATC).
Could there be any damage on motor or drive if I double the maximum frequency?
The MP620 did have different options of 1500, 3000 or 4500 but that was done by different pulleys.

From what I have read a motor has a base rpm, voltage and frequency eg. 2800rpm 230V 50Hz (Swedish standard)
At lower speed it will reduce both voltage and frequency and if you go higher then base frequency the VFD cant deliver the correct voltage since it is higher than voltage supplied to the VFD.
That will result in a higher speed but lower torque and somewhere it will stall depending on the load.
It will look something like this:
280rpm = 23V 5Hz
1400rpm 115V 25Hz
2800rpm 230V 50Hz
5600rpm 460V 100Hz (here is only 230V supplied and that result in only 50% torque)
In this case I dont need much torque when using the driven tools in high speed since high speed = small tool so I will do some testing with this.
But first I have to find out how fast I can run the tools but I know 4500rpm is OK.