What is the maximum power output from the practiSPIN system?
That obviously depends on which device you are using. As with most power devices, the maximum output current is limited by the dissipation, not the maximum rating of the device. For a typical application using the L6208PD, the device can deliver in the range of 1.75 A continuously in both bridges. With a 48V rated motor, you are looking at about 150 W total output.
