in a wound rotor motor, connect the rotor to a wound rotor controller.

adjust the resistance in rotor controller. Why the lager resistance value the controller is, the more frequency will be.

 

your question doesn't make sense to me, but maybe you can find the answer here.

Motor speed may be varied by putting variable resistance back into the rotor circuit. This reduces rotor current and speed. The high starting torque available at zero speed, the down shifted break down torque, is not available at high speed. See R2 curve at 90% Ns, Figure below. Resistors R0R1R2R3 increase in value from zero. A higher resistance at R3 reduces the speed further. Speed regulation is poor with respect to changing torque loads. This speed control technique is only usefull over a range of 50% to 100% of full speed. Speed control works well with variable speed loads like elevators and printing presses.

 

your question doesn't make sense to me, but maybe you can find the answer here.

I have read that article... but i can't find the answer. thanks anyway

 

in a wound rotor motor, connect the rotor to a wound rotor controller.

adjust the resistance in rotor controller. Why the lager resistance value the controller is, the more frequency will be.

By frequency do you mean speed?