... prevented 2.12KW, 21KW, 31KW 3.CE,ISO Stars Progressing cavity pump motor and driver for oil extraction ---NAS-B SeriesThis system ... or Hot humid areas. Large torque of overload can resist pump blocked by sand, and apply to general oil well, ... capacity.Braking controlled by electromagnet, prevention of reverse rotation, rotary inertial auto-released tardily while power off.Automatic Data recording ...