if your DC moto is low power supply,and brushness then the volt may be 6v,9v,12v,24v.......48v.
DC moto's speed relate to the voltage.,and DC moto's torsion relate to the current.
you can use a DC voltage supplier give power to your moto,from zero voltage.
And you use an encoder or other devise,to detect your moto's speed.
The speed will accelerate along with you enhance the DC supplier's voltage.
Once you fine the moto gets its MAX speed from a voltage(even if the voltage you give to the moto is more higher,the moto's speed will no more fast.)for example:3000rad/min from 22V to more higher voltage.Then,your moto's MAX speed is 3000rad/min,and the supply voltage should be 24V.
you may ask:why no 22V? Because the moto's load is empty,so it can get its MAX speed at 22V.
But how to fine the MAX current which your moto can use,is more difficult. You should use a torsion sensor to detct the torsion on the moto's out-axis,and supply a slowly enhace current to your moto on the condition of the voltage which you have got above. if the torsion gets MAX, then the current is you need.
if it is necessary, I can sand you the protel schedule from E-mail.
you can contact me :
aaaaaaaaaalyl@163.com