EFFECT OF LOBE CONFIGURATION ON TORQUE AND SPEED
The rotor and stator are designed as helical elements with a major and minor diameter. The lobe is a curved spiral shape formed by the difference in the major and minor diameters.
The stator has one more lobe than the rotor. The difference in lobes creates a fluid inlet area (cavity) into which fluid can be pumped to create rotation. A stage is the distance measured parallel to the axis between two corresponding points of the same spiral lobe. This distance is commonly referred to as the lead of the stator.
The torque and speed rate can be varied by changing lobes and stages. A motor with more lobes can generate more torque; a motor with fewer lobes can have a higher rotational speed rate. On the other hand, the torque can be increased by adding more stages.
There are two ways to increase torque: First, increase the number of rotor/stator lobes; second, increase the number of stages of the power section.