I'm attempting to put a frame around my section headings.  I am using the package mdframed which adds functionality to the framed package.  It basically draws a box around an object, in an environment.  So I wonder how I can do this.  Can I use \renewcommand, for example?  I'd really like to use mdframed to create the frame.


Question: drive 3 phase induction motor with only DC (not pwm) thru each phase
Answer: You may be considering a simple 3phase AC inverter design or a powerful high torque variable frequency drive (VFD) electronics.   Your choice depends on detailed specs including torque vs speed and budget. In both cases, a square wave would not be desireable as the eddy current losses would be excessive so multi-level low impedance drive is needed to appropximate the sine wave.