The 90-volt DC motor provides far more than that of the 1/2 HP AC/DC motor we used to offer prior to 1994. A DC motor offers its maximum torque at low RPM where you need it most, so the full speed horsepower rating of an AC/DC motor can be a little deceiving as far as offering practical, useable power. The DC motor also offers smoother and quieter operation. The motor now features externally replaceable brushes, making replacement of worn brushes a simple task taking just a few minutes.