Techniques are provided for protecting a twin screw positive displacement pump, that include a signal processor that receives signaling containing information about power, torque, speed, viscosity and specific gravity related to the operation of the twin screw positive displacement pump; and determines whether to enter an enhanced pump protection mode for the twin screw positive displacement pump based on a relationship between an actual corrected tune ratio and a tuned ratio set point (Tune Ratio SP). In operation, the signal processor determines if the actual corrected tune ratio is<=the actual corrected tune ratio set point (Tune Ratio SP), and if so, then enters the enhanced pump protection mode, else continues to use a basic pump protection mode, and also determines the actual corrected tune ratio based on a ratio of an actual corrected torque (TAcorr) divided by a tuned corrected torque (TTcorr) at a specific operating speed.

An arrangement (100) for specifying the pressure (64), produced by a pump (30) driven by an electric motor (31), includes a processor (116) which derives a target pressure value (62, 118) from an internal torque value (114) and a loss torque (108). The arrangement (100) further derives (112) the internal torque value (114) from a motor current value (110) and a motor constant k.sub.e.

The present disclosure describes a load/unload control method for a compressor system with a rotating compressor connected to a pressure vessel. In the method, the present operating state can be monitored on the basis of a monitored/estimated electrical quantity of the compressor system. The method comprises an identification phase and an operational phase. In the identification phase, the compressor is operated at a constant rotational speed to generate two known pressures to the pressure vessel. At least one electrical quantity is monitored, and values of the electrical quantity corresponding to the pressure limits are stored. In the operational phase, reaching of a pressure limit may then be detected by comparing the present value of the monitored electrical quantity to the stored values.

A water pumping system, a motor drive, and a method of starting pumping by the motor drive. The method includes performing repeated starting attempts to overcome stiction in a progressive cavity pump by attempting to supply power to an electrical motor at increasing power levels in each starting attempt and supplying the power at the increasing power levels if the power is available in from a power source; and after each starting attempt: reducing the power applied to the electrical motor to a reduced power level; determining a rotational speed of the electrical motor; determining if the rotational speed matches a speed corresponding to the reduced power level applied to the electrical motor; if the rotational speed does not match and a predetermined number of starting attempts has not been reached, performing a next starting attempt; and if the rotational speed does match, entering a normal mode of operation.

An electric oil pump device includes an electric oil pump and a microcomputer that acquires a static friction torque of a pump and a motor of the electric oil pump, and performs control of activating the electric oil pump based on the acquired static friction torque.

A water pumping system, a motor drive, and a method of starting pumping by the motor drive. The method includes powering the electric motor with a motor drive; driving a progressive cavity pump with the electric motor; monitoring a speed difference between an electrical speed and an observed speed of a rotor of the electric motor; and performing a protective action as a function of the speed difference.

An electric pump includes a motor portion having a rotary drive force by a power supply, a pump portion being operated by the motor portion, and a control portion controlling an electric power being supplied to the motor portion. The motor portion, the pump portion, and the control portion are integrally formed. The control portion includes a control circuit board controlling the electric power supplied to the motor portion, the control portion including a case containing the control circuit board, the control portion including a temperature sensor being provided at a board surface of the control circuit board, the board surface being disposed at a position facing an inner surface of an area of the case, the area being exposed to external air.

A method for controlling the speed of a compressor with a controller as a function of the available gas flow comprising the following steps: setting a desired value for the inlet pressure; determining the inlet pressure; determining the speed; controlling the speed of the compressor by reducing or increasing it depending on whether the inlet pressure is less than or greater than the set desired value until the inlet pressure is equal to the set desired value; providing the characteristic data of the compressor relating to the efficiency and/or the Specific Energy Requirement (SER) as a function of the speed and the inlet pressure; adjusting the desired value of the inlet pressure on the basis of the aforementioned characteristic data and in such a way that the efficiency of the compressor is a maximum or the SER is a minimum.

A hydraulic transmission control system including a vane pump including a stroke ring defining a compartment. An outlet line and an inlet line are fluidly connected to the compartment. A control pressure chamber and a compensation chamber are defined adjacent to opposite sides of the stroke ring, each for varying a pump outlet pressure based on a pressure change within the chambers. A pump controller is connected to the outlet line and the pressure control chamber for adjusting a pressure in the pressure control chamber. The outlet line is further connected to the compensation chamber, a primary hydraulic circuit and a primary pressure control valve. A secondary hydraulic circuit is connected to the primary pressure control valve. A shift valve is disposed between the outlet line and the primary control valve and configured to selectively connect the pump controller and the primary pressure control.

Techniques are provided for protecting a twin screw positive displacement pump, that include a signal processor that receives signaling containing information about power, torque, speed, viscosity and specific gravity related to the operation of the twin screw positive displacement pump; and determines whether to enter an enhanced pump protection mode for the twin screw positive displacement pump based on a relationship between an actual corrected tune ratio and a tuned ratio set point (Tune Ratio SP). In operation, the signal processor determines if the actual corrected tune ratio is<=the actual corrected tune ratio set point (Tune Ratio SP), and if so, then enters the enhanced pump protection mode, else continues to use a basic pump protection mode, and also determines the actual corrected tune ratio based on a ratio of an actual corrected torque (TAcorr) divided by a tuned corrected torque (TTcorr) at a specific operating speed.