Motor Section
This is a reverse application of Rene Moineau’s pump principle. The motor
section consists of a rubber stator and steel rotor. The simple type is a
helical rotor which is continuous and round. This is the single lobe type.
The stator is molded inside the outer steel housing and is an elastometer
compound. The stator will always have one more lobe than the rotor.
Hence motors will be described as 1/2, 3/4, 5/6 or 9/10 motors.
Both rotor and stator have certain pitch lengths and the ratio of the pitch
length is equal to the ratio of the number of lobes on the rotor to the
number of lobes on the stator.
As mud is pumped through the motor, it fills the cavities between the
dissimilar shapes of the rotor and stator. The rotor is forced to give way by
turning or, in other words, is displaced (hence the name). It is the rotation
of the rotor shaft which is eventually transmitted to the bit.
This is a reverse application of Rene Moineau’s pump principle. The motor
section consists of a rubber stator and steel rotor. The simple type is a
helical rotor which is continuous and round. This is the single lobe type.
The stator is molded inside the outer steel housing and is an elastometer
compound. The stator will always have one more lobe than the rotor.
Hence motors will be described as 1/2, 3/4, 5/6 or 9/10 motors.
Both rotor and stator have certain pitch lengths and the ratio of the pitch
length is equal to the ratio of the number of lobes on the rotor to the
number of lobes on the stator.
As mud is pumped through the motor, it fills the cavities between the
dissimilar shapes of the rotor and stator. The rotor is forced to give way by
turning or, in other words, is displaced (hence the name). It is the rotation
of the rotor shaft which is eventually transmitted to the bit.
