| abstract |
A modular motor, suitable for use in downhole (wellbore) pumping systems and electric submersible pumps (ESPs), includes a number of modules 60. Interlocking splines may be used to couple the rotors (92, 94); alternatively, a single rotor extending throughout the modular stators may be used. The motor modules may be collectively inserted into a single tube 106 (fig.12), which is swaged to secure the modules. Inner and outer rotor configurations are disclosed. A flowpath 81 may exist through the motor. The use of conventional and magnetic bearings is disclosed. Each motor section comprises a brushless dc motor in which the stator 33 and its windings are enclosed (canned) in an annular chamber 36 created by a non-magnetic sleeve 34, and sealed by static (non-rotating) O-ring seals (38, 39, fig.4) . The chamber includes temperature /pressure compensation means 40 in the form of a moveable plug. This arrangement overcomes the disadvantages of earlier motor protectors using elastomeric bags, which are susceptible to damage by well fluids and contaminants such as hydrogen sulphide (sulfide). |