"Thanks so much Phil so it means they are DC motors? or they use pulsating DC. What is the typical voltage "

He said three phase. That means that while you might feed it DC, the board generates a three phase output to drive the coils, making brushes unnecessary. It also might be a VFD (variable frequency).

There is no typical voltage, though many just use rectified mains power to save money.

Bottom line is it needs the board to run. It is not an inverter.