There is disclosed a pump apparatus which can more accurately determine the occurrence of an abnormal vibration. The pump apparatus includes: a pump; an electric motor for driving the pump; an inverter as a speed changing means for the electric motor; a vibration detector for detecting at least one of a vibration of the pump, a vibration of the electric motor and a vibration of the inverter; and a controller for controlling the pump. The controller includes a storage unit for storing a measured vibration value measured by the vibration detector. The storage unit has a storage table which, when the rotational speed of the pump is increased stepwise to a predetermined rotational speed, stores the measured vibration value measured at each step.

An electric oil pump includes a motor part having a shaft, a pump part located on a front side of the motor part and driven via the shaft, and a control part controlling the motor part. The motor part includes a rotor, a stator, and a motor housing accommodating the rotor and the stator. The pump part includes a pump rotor mounted on the shaft protruding from the motor part, and a pump housing accommodating the pump rotor. The control part includes a substrate having a surface on which a plurality of electronic components are mounted. The surface of the substrate is disposed to face the cylindrical portion of the motor housing and extends in the axial direction. The substrate has an axial length shorter than an axial length of an assembly of the motor part and the pump part and is disposed within an axial range of the assembly.

A heat pump device includes a compressor that compresses refrigerant, a motor that drives the compressor, an inverter that applies a desired voltage to the motor, and an inverter controlling unit that generates a pulse width modulation signal for driving the inverter, has, as operation modes, a heating operation mode performing heating operation of the compressor and a normal operation mode performing normal operation of the compressor to compress the refrigerant, and periodically changes carrier frequency, that is frequency of a carrier signal, in the heating operation mode.

An electric compressor includes a compression member configured to compress fluid, an electric motor configured to drive the compression member, an inverter configured to drive the electric motor, a housing accommodating the compression member, the electric motor, and the inverter, and a soundproof cover covering the housing. The housing includes a plurality of housing elements. The soundproof cover has a facing portion facing the housing. The facing portion has a groove that surrounds a boundary between two of the housing elements that are adjacent to each other and is distant from the boundary.

In order to reduce operation in a rotation-prohibited frequency range and to prevent resonance in a gas compressor wherein inverter control is performed, this gas compressor has: a compressor main body that compresses a gas; a motor that rotationally drives the compressor main body; an inverter that changes the rotational speed of the motor; a check valve arranged downstream from the compressor main body; a pressure detection means that detects load-side pressure downstream from the check valve; and a control device that, in accordance with the pressure detected by the pressure detection means, controls the frequency output by the inverter. The control device performs a control whereby compressed gas having a prescribed pressure is generated/maintained by increasing/decreasing the frequency, and when the frequency that generates the compressed gas having the prescribed pressure includes a specific frequency, the inverter's output frequency is increased or decreased when the pressure detected by the pressure detection means reaches a pressure corresponding to a frequency that has a more constant pressure width than the prescribed pressure and does not include the specific frequency.

A technique is provided that can further reduce power at the time of “unload operation control” in a gas compressor that generates a compressed gas at a set pressure by constant-speed control. The gas compressor includes a compressor main unit, a drive source, an intake throttle valve, a gas release valve, rotation speed converting means, a pressure detecting device that detects a discharge pressure, and a controller that, the relationship between an upper-limit pressure H and a lower-limit pressure L being H>L, carries out opening the intake throttle valve and closing the gas release valve and operating the drive source at a full-load rotation speed until the discharge pressure reaches the upper-limit pressure H. The controller carries out at least one of closing the intake throttle valve and opening the gas release valve to reduce the discharge pressure to within a predetermined range when the discharge pressure reaches the upper-limit pressure H. The controller carries out switching to load operation when the discharge pressure drops to the lower-limit pressure L. In the gas compressor, the controller outputs a command of a lower rotation speed than the full-load rotation speed to the rotation speed converting means when the discharge pressure rises and reaches the upper-limit pressure H. The controller outputs a command of the full-load rotation speed to the rotation speed converting means when the discharge pressure drops and reaches the lower-limit pressure L.

A portable oxygen concentrator includes a compressor and a controller. The compressor includes a motor, at least one chamber, and at least one piston operably coupled to the motor and movable within the at least one chamber. In some embodiments, the controller is configured to: determine actual motor speeds for commutations steps of the motor during a first rotational cycle; determine an average motor speed during the first rotational cycle; determine a voltage pattern based at least on a comparison of the average motor speed during the first rotational cycle and the actual motor speeds for the commutation steps of the motor during the first rotational cycle; and cause the voltage pattern to be applied to the motor during a second rotational cycle to reduce differences between applied motor torque and variable torque load imparted by the at least one piston.

A compressor includes a motor including three-phase coils having 6N terminals (where N is an integer), a compression mechanism configured to be driven by the motor, a closed container in which the motor and the compression mechanism are housed, a terminal portion electrically connected to the 6N terminals of the coils and protruding outside the closed container, a conductor portion attached to at least a part of the terminal portion to thereby fix a connection state of the coils, and an insulating body covering at least the conductor portion.

An object of the present invention is to provide a rotary displacement compressor capable of determining whether a check valve has failed, and preventing the life of a compressor body from being reduced when a compression operation stops. In order to achieve the object, a rotary displacement compressor includes a compressor body that compresses a medium by reducing a volume of the medium using rotation; a discharge pipe through which a compressed medium, which is discharged through a discharge port of the compressor body, flows; a check valve that shuts off the compressed medium flowing backward to the compressor body; and a backflow control valve that allows a predetermined rate of the compressed medium to flow backward. The check valve and the backflow control valve are disposed in series via the discharge pipe.

To reduce the possibility that temperature of refrigerant discharged from a compressor of a refrigeration apparatus becomes excessively high by controlling torque of a motor built into the compressor, the compressor includes the motor having rotation thereof controlled by inverter control. An inverter controller controls torque of the motor using inverter control when operation frequency of the compressor is at least one value within a range of from 10 Hz to 40 Hz. When at least the operation frequency is within the range of from 10 Hz to 40 Hz, torque of the motor is controlled, and under a predetermined condition in which temperature of refrigerant discharged from the compressor easily becomes excessively high, a device controller controls devices provided in a refrigerant circuit such that refrigerant sucked into the compressor is placed in a wet vapor state.