DC Motor controller

I have not used this part but it looks simple. (uses a p-fet) But it looks like it would take 60 to 70V and buck it down to run the motor. It the running current is 10A you probably need a 20 to 30A supply. That might be too much for a p-MOSFET.
Here is another higher current option. N-MOSFETs Should run with less losses. I have not used this exact part but parts like this.
so many options are available and my best and simplest option is building a power supply system that has variable output from 0 to 50 volts. So you need to regulate the voltage from the 240vac to the required variable output.