Abstract: A variable speed controller is provided which utilizes a combination of pulse width modulation and fixed pulse control, such as a conventional six-step control, in order to generate multiphase sinusoidal power signals for use by downhole wellbore equipment, such as electrical submersible pumps. A controller is utilized to monitor at least one DC voltage level of the rectifier and/or inverter circuit of a variable speed controller. The DC level is compared to an optimum DC level. A triggering threshold is established. Once the triggering threshold is surpassed, the controller is utilized to switch between a conventional six-step mode of control and a pulse width modulation mode of control in order to better respond to a positive transient voltage condition. The pulse width modulation mode of operation provides for real time counteracting of the positive transient condition.

Abstract: A gas-liquid separator, especially for use with a submersible well pump, having a substantially conical-shaped mesh member in the path of flow of gas-laden liquid. The majority of the liquid flows through the mesh; gas bubbles are trapped by the mesh and are swept by the flow of the liquid to a location where they are removed with a relatively small amount of bleed liquid from the separator Any particulate foreign matter in the gas-laden liquid, is trapped by the mesh and is swept along with the gas bubbles to the gas removal location.

Abstract: Low voltage starting of a three-phase submersible pump motor in a shallow well is achieved by employing a high-impedance transformer for supplying the three-phase power to the motor. Upon starting, the normally heavy current drawn by the motor results in a voltage drop through the high-impedance transformer sufficient to substantially lower the voltage across the motor and hence the starting current. In the absence of limiting the starting current, abnormally high starting torques will be produced on the motor shaft resulting in mechanical fatigue and eventually shaft breakage.

Abstract: Electrical conductors having suitable combinations of coatings and coverings are disclosed which have the ability to inhibit low molecular weight hydrocarbon well fluids when under pressure and withstand high proportions of gassy hydrocarbons under pressure without undergoing rupture failure.

Abstract: A tandem thrust bearing arrangement associated with a rotating shaft which is subjected to an axial load having spaced first and second annular members or thrust runners fixed to the shaft and first and second thrust bearings associated with the respective annular members and means axially movable with respect to the shaft supporting one of the thrust bearings which activates pivotable means applying load to the other thrust bearing.

Abstract: A cable splice comprising a metallic sleeve member joining the conductor ends, a layer of adhesive over the sleeve member adjacent insulation and lead sheath, a helically-wrapped insulation layer formed of a thermosetting polymer, an overlapped layer of fabric surrounding the insulation layer, an overlapped layer of lead foil surrounding the fabric layer and extending over the lead sheath a helically-wrapped heat-shrinkable tape layer surrounding the lead foil layer and a heat-shrinkable sleeve surrounding the splice area which resists invasion by corrosive well fluids and consequent corrosive in high pressure gassy wells, and a method for forming said cable splice.