The invention relates to a pump system comprising a positive-displacement pump module, preferably a screw pump, a drive module which can be exchanged separately from the positive-displacement pump module, said drive module comprises an electric drive motor and a frequency converter associated therewith for controlling or adjusting a drive motor speed, control means comprising a controller for producing an adjustment variable (Y.sub.S) for the frequency converter in accordance with a reference variable (W) and a first actual operational parameter (X) and logistic means associated with the controller, and reference variable defining means for providing the reference variable (W) for the control means. According to the invention, the control means are provided in a control module separately from the drive module, and the drive module can be exchanged separately from the control module, and the drive module does not have a designed and/or controlled controller for producing the adjustment variable (Y.sub.S).

A method of controlling a liquid ring pump in a pump system includes monitoring a vacuum pressure of the liquid ring pump using a pressure transmitter configured to transmit a vacuum pressure signal to a controller in operative communication with the liquid ring pump. The method also includes maintaining a predetermined vacuum pressure in the liquid ring pump under variable vacuum flow demand within the pump system in response to the vacuum pressure signal by controlling, via instructions from the controller, a parameter of the liquid ring pump based on a comparison of the vacuum pressure signal to the predetermined vacuum pressure by the controller.

A pump assembly and a method for sensing rotary motion of the pump therein are disclosed. The pump assembly includes a pump, a controller, and an optional driven electric motor. The components may be axially aligned and mounted relative to one another. The controller includes a circuit board that is oriented in an axial direction of the pump assembly so that it faces in a radial direction. A 3D rotary sensor is mounted on the circuit board and is designed to detect motion parallel to its front face and motion in a plane perpendicular to its front face, including rotary motion of the pump, for output to the controller. The controller is configured to control the pump via controlling the drive shaft of the motor or pump.

The invention relates to a pump system comprising a positive-displacement pump module, preferably a screw pump, a drive module which can be exchanged separately from the positive-displacement pump module, said drive module comprises an electric drive motor and a frequency converter associated therewith for controlling or adjusting a drive motor speed, control means comprising a controller for producing an adjustment variable (Y.sub.s) for the frequency converter in accordance with a reference variable (W) and a first actual operational parameter (X) and logistic means associated with the controller, and reference variable defining means for providing the reference variable (W) for the control means. According to the invention, the control means are provided in a control module separately from the drive module, and the drive module can be exchanged separately from the control module, and the drive module does not have a designed and/or controlled controller for producing the adjustment variable (Y.sub.s).

The embodiments disclosed herein are directed to systems and methods to control a HVAC system based on a state of an unloader of a compressor of the HVAC system.

A rotary-vane internal combustion engine of the cat and mouse or scissor type with coordinated rotation of two co-axial shafts with position sensors creating chambers of variable volume for intake, compression, power and exhaust strokes. A reversible electric generator motor on at least one of the shafts with an electronic control system for current, an energy storage unit and electrical load. The total work done and angular speed is calculated or empirically determined while an alternating accelerating or decelerating torque is applied for a continuous, uniform rotation cycle.

A motor-driven compressor is provided with a motor including a rotor, a housing including an inlet through which low-pressure refrigerant serving as a low-pressure fluid is drawn in, a compression unit that compresses the low-pressure refrigerant and discharges compressed high-pressure fluid, an inverter that drives the motor, and a controller that controls the inverter. If the rotor is activating in a reverse direction that is opposite to a forward direction when activating the motor, the controller obtains a position of a d-axis of the rotor and controls the inverter so that current flows to the obtained d-axis and so that frequency of current flowing to the motor decreases as time elapses.

A pump assembly is provided and includes a housing having first, second and third pairs of fluid openings and first, second and third rotary pumps, which are co-rotatable about a common longitudinal axis defined through the housing to drive fluid flow relative to the first, second and third pairs of fluid openings, respectively. The first rotary pump includes an input member receptive of rotational drive energy for the first, second and third rotary pumps.

Exhaust gas recirculation pump (30) for an internal combustion engine that includes an electric motor (32) disposed within a housing (36). A Roots device (38) is coupled to the electric motor (32) and includes a housing (40) defining an internal volume (42) in which rotors (44) are disposed and are connected to the electric motor (32). The electric motor housing (36) includes a coolant path (48) formed therein which extends from a coolant inlet (58) to a coolant outlet (78), both coupled to an engine coolant circulation system. The housing includes an oil path (108) formed therein. The oil path includes an oil inlet (110) extending to at least one oil outlet (112). The oil inlet and outlet are coupled to an engine oil circulation system wherein the oil path (108) lubricates bearings (100) and a transmission assembly (46) of the exhaust gas recirculation pump (30).

The present invention provides an oil pump device capable of preventing foreign matters from getting caught at a sliding part of an oil pump, and thus of preventing a situation where the oil pump is locked and prevented from rotating. The oil pump device includes an oil pump connected to a supply target apparatus by a hydraulic circuit, the oil pump discharging and supplying oil to the supply target apparatus through the hydraulic circuit; a motor driving the oil pump; a trapping member interposed along the hydraulic circuit, the trapping member trapping a foreign matter mixed in the oil discharged from the oil pump; and a motor control unit controlling the motor to perform a normal control mode of driving the oil pump in a normal control rotation range and perform, at operational start of the oil pump, a lock-avoiding mode of driving the oil pump with a lock-avoiding rotational speed set in advance as a lower limit.