A control method and a control device applied to an electric fracturing apparatus are provided. The electric fracturing apparatus includes a plunger pump and a first motor configured to drive the plunger pump, and the method includes: acquiring a preset displacement of the plunger pump; acquiring a rotation speed of the first motor and a discharge pressure of the plunger pump; determining a real-time displacement of the plunger pump based on the rotation speed of the first motor and the discharge pressure of the plunger pump and adjusting the real-time displacement; and upon the real-time displacement reaching the preset displacement, allowing the first motor to be kept in a stable operation state.

The controller for an actuator that is driven by a brushless motor estimates the temperature of the magnet in the brushless motor on the basis of an electric current value and a rotation speed thereof which are obtained by supplying power to rotate the brushless motor in a reverse direction, and limits current flowing through the brushless motor during forward rotation so as to prevent the magnet temperature from rising beyond an allowable maximum temperature. Limiting the current flowing through the brushless motor on the basis of the estimated magnet temperature makes it possible to drive the brushless motor while preventing the magnet temperature from rising beyond the allowable maximum temperature without providing the brushless motor with any temperature sensor for detecting the magnet temperature therein.

A refrigerant compressor includes an electric motor. A current sensor measures current to the electric motor. A switching device is configured to close and open to allow and prevent current flow to the electric motor, respectively. A maximum continuous current (MCC) device generates an output that one of: (i) is an MCC for the electric motor and (ii) is a value indicative of the MCC for the electric motor. A motor protection module: is remote from the MCC device; receives the output wirelessly from the MCC device via an antenna; one of sets a first MCC to the MCC for the electric motor and determines the first MCC based on the value indicative of the MCC for the electric motor; selectively sets a predetermined MCC to the first MCC; and controls the switching device based on a comparison of the current to the electric motor and the predetermined MCC.

A refrigerant compressor includes an electric motor. A current sensor measures current flow to the electric motor. A switching device is configured to close and open to allow and prevent current flow to the electric motor, respectively. A maximum continuous current (MCC) device includes a stored digital value corresponding to a maximum continuous current for the electric motor. A motor protection module: communicates with the MCC device, the current sensor, and the switching device; determines a first MCC for the electric motor as a function of the stored digital value received from the MCC device; selectively sets a predetermined MCC to the first MCC; and controls the switching device based on a comparison of the current flow to the electric motor and the predetermined MCC.

An air treatment system includes an electric compressor for compressing air, an air flow valve positioned in a delivery line downstream of the electric compressor, and an electropneumatic valve connected to the air flow valve. A controller having control logic receives a system pressure and activates the electropneumatic valve. The control logic activates the electropneumatic valve to provide a pneumatic control signal to the air flow valve to partially close the delivery line in response to the system pressure being greater than a first predetermined pressure.

An air compressor includes a tank unit, a compressed air generating unit, a motor unit, a driving current generating unit, a control unit and a temperature detecting unit. The tank unit stores a compressed air. The compressed air generating unit generates the compressed air to be stored in the tank unit. The motor unit drives the compressed air generating unit. The driving current generating unit generates a driving current of the motor unit. The control unit drives the motor unit by controlling the driving current generating unit. The temperature detecting unit detects a temperature of the driving current generating unit. The control unit changes the driving current of the motor unit by controlling the driving current generating unit based on the temperature detected by the temperature detecting unit.

A system, method, and computer-readable medium for determining the flow rate and fluid density in an electrical submersible pump (ESP) and controlling the ESP based on the flow rate and density. In one implementation, an ESP system includes an ESP, drive circuitry, a current sensor, a voltage sensor, and a processor. The ESP includes an electric motor. The drive circuitry is electrically coupled to the ESP and is configured to provide an electrical signal to power the ESP. The current sensor is configured to measure a current of the electrical signal. The voltage sensor is configured to measure a voltage of the electrical signal. The processor is configured to calculate speed of a shaft of the electric motor based on a frequency induced by rotation of the motor detected in the current. The processor is also configured to calculate a density of fluid in the ESP based on the speed.

An auxiliary device for pumps, comprising a device body which defines a conveyance duct, which can be connected to the delivery of a pump driven by an electric motor, and at least one accommodation portion for an electronic controller which is connected to at least one sensor for detecting at least one operating parameter correlated to the operation of the pump. The electronic controller is functionally connected to a short-range wireless communication unit which can be configured to communicate with to at least one mobile device operated by a user.

A compressor for a commercial vehicle comprises: a plurality of cylinders, wherein each cylinder accommodates a reciprocating piston, wherein the reciprocating piston is driven by a crankshaft, and a plurality of cooling means, arranged at a cylinder head region of the cylinder, wherein one specific cooling means is assigned to one cylinder respectively.

The compressor assembly comprises a sensor network, wherein the sensor network comprises a plurality of temperature sensitive switches, wherein each temperature sensitive switch is assigned to a cylinder.

A drive system for a fluid displacement pump includes an electric motor, a drive coupled to the rotor at a first end of the electric motor, a pump including a fluid displacement member mechanically coupled to the drive, and a controller configured to control a level of power to the electric motor based on a pressure setting set by a user. The electric motor includes a stator and a rotor disposed on an axis. The drive coupled to the rotor converts the rotational output to a linear, reciprocating input to power a pump.