Smaller motor for pumps improves performance
This company has recently extended its focus on motor applications to include positive displacement pumps. Peristaltic pumps require relatively high torque at low rotational speeds, typically in the range of 5 to 500 rpm, well below the direct-drive capability for incumbent, conventional a.c. or d.c. motors. As a result, incumbent motors are operated at a higher speed (over 1,000 rpm) and a speed-reduction gearbox is necessary to achieve the required torque and rotational speed. As a result, these geared-drive systems can be large, heavy and inefficient. Also, the gearbox increases cost, while causing a reliability and maintenance burden. Compared to these conventional geared systems, the direct-drive motors deliver high continuous torque at low rotational speeds, which eliminates the need for a speed-reduction gearbox and reduces the drive system size and weight (photo). The motors use transverse flux technology with increased pole count and low resistance coils, delivering 5–10 times more continuous torque by mass compared to conventional a.c. or d.c. motors. And, according to the company, compared to the a.c. geared system, power consumption versus pump speed is reduced 29–54% for the direct-drive system. — Electric Torque Machines (ETM), Flagstaff, Ariz.