Abstract: In some aspects, the techniques described herein relate to a refrigerant compressor, including: an impeller; a shaft; a motor configured to rotate the impeller via the shaft, wherein the motor includes a stator and a rotor; and a housing surrounding the motor, wherein the housing includes a first inlet configured to permit fluid to enter the housing and flow along a stator cooling line and a second inlet configured to permit fluid to enter the housing and flow a rotor cooling line, and wherein the first inlet is separate from the second inlet.

Abstract: This disclosure relates to a refrigerant compressor including an impeller. The impeller has a blade with a wavy contour. The wavy contour reduces flow separation relative to smooth, non-wavy blades. In particular, the disclosed wavy contour creates smaller trailing edge vortexes adjacent the blades. In turn, the wavy contour of the blades improves overall compressor efficiency.

Abstract: A circuit arrangement and a method for actuating a power semiconductor switch wherein said power semiconductor switch has a load current input, a load current output and a control input, having a first voltage detection device, which is able to be switched on and off, for detecting a first voltage present between the load current input and the load current output, a second voltage detection device, which is able to be switched on and off, for detecting a second voltage present between the control input and the load current output, and having a regulating device that is designed to cyclically assess a second voltage value of the second voltage and, if a second threshold value of the second voltage value is reached, to switch on the first voltage detection device, in particular if no further fault signal is present.

Abstract: A circuit arrangement and a method with a DC voltage supply, a DC voltage intermediate circuit, a power converter, a control device for the power converter, and with a braking resistor. The power converter is formed as a multi-phase bridge circuit having at least one, preferably at least two first half bridge circuit(s) and having at least one, preferably at least two second half bridge circuit(s), which are each connected to the DC voltage intermediate circuit. A first resistor terminal of the braking resistor is connected to the middle tap of the first bridge circuit, and wherein a second resistor terminal of the braking resistor is connected to the middle tap of the second bridge circuit.

Abstract: A plate kind heat exchanger (1) has a plurality of stacked plates (2) forming flow paths for heat exchanging fluids there between, a first inlet channel being fluidly connected to inlets of a first set of flow paths, a second inlet channel being fluidly connected to inlets of a second set of flow paths, a first outlet channel being fluidly connected to outlets of the first set of flow paths, and a second outlet channel being fluidly connected to outlets of the second set of flow paths. The first inlet channel is provided with a stack (15) of rings (5) forming fluid passages towards the inlets of the first set of flow paths.

Abstract: An arrangement and methods for operating and for determining the speed of an electrical machine connected to a power electronic switching device and for supplying energy to a control device of the power electronic switching device. The arrangement and methods have an inductive decoupling device arranged on an electrical conductor leading from the switching device to the electrical machine, wherein a frequency determination device is used to determine the frequency of a voltage associated with a current in the electrical conductor and thus indirectly the speed of the electrical machine, and wherein a rectified output voltage of the decoupling device forms a voltage source for the control device.

Abstract: A power semiconductor module has a base plate with a housing and a switching device. The switching device has a substrate and a connecting device with a first and a second main face. A group of power semiconductor components is arranged on a conductor track of the substrate, and has a group midpoint. A pressure device is formed on the substrate in the normal direction to exert pressure, which pressure device has a pressure body and a pressure inducing body, wherein a pressure element is arranged protruding from the pressure body, wherein the pressure element presses onto a pressure section of the second main face of the connecting device, and wherein the pressure inducing body has a pressure transmission section with a pressure transmission point.

Abstract: The invention relates to a compressor unit (200) for a refrigeration system using a refrigerant. The compressor (200) unit includes a centrifugal compressor (201) for compressing the refrigerant, wherein the compressor (201) has a discharge outlet (204) for discharging the compressed refrigerant, and a check valve (1; 100; 301a). An inlet (83) of the check valve (1; 100; 301a) is in fluid connection with the discharge outlet (204) of the compressor (201). In order to provide a more reliable and more quite compressor unit (200), the check valve (1; 100; 301a) is a nozzle check valve including a damping mechanism (41, 50; 50, 141), wherein a closing parameter of the check valve (1; 100; 301a) is between 50 s/m2 and 2000 s/m2, wherein the closing parameter is a closing time of the check valve (1; 100; 301a) divided by a port area of the check valve (1; 100; 301a).

Abstract: A plate heat exchanger includes a plurality of heat transfer plates stacked on top of each other, wherein gaskets are positioned between adjacent heat transfer plates, wherein each gasket is arranged in a gasket groove formed in a heat transfer plate and a bottom part of the gasket groove defines a base level, wherein the gasket groove comprises a reinforcing pattern having a first recess at a first recess level and extending in a lengthwise direction of the gasket groove. The reinforcing pattern comprises a second recess at a second recess level extending in lengthwise direction of the gasket groove.

Abstract: A valve arrangement includes a housing arrangement (12), (18), a first spool valve (1a, 1b) having a first spool (3a, 3b) and a second spool valve (2a, 2b) having a second spool (4a, 4b), wherein the first spool valve (1a, 1b) and the second spool valve (2a, 2b) each includes a supply channel arrangement having a pump channel (5) and a tank channel (6), and a working port arrangement having two working ports (8, 9), wherein the spools (3a, 3b; 4a, 4b) control a flow path between the supply channel arrangement (5, 6) and the working port arrangements (7, 8). In such a valve arrangement, it should be possible to simply adapt the control behaviour to different purposes. To this end, the working port arrangement (7, 8) is arranged in a flange (16a, 16b) connected to the housing arrangement (13, 14; 19, 20).

Abstract: A method for controlling a vapour compression system (1) including a compressor unit (2) including one or more compressors (3, 12), a heat rejecting heat exchanger (4), a receiver (6), an expansion device (7) and an evaporator (8) arranged in a refrigerant path. A pressure value indicating a pressure prevailing inside the receiver (6) is obtained, and the obtained pressure value is compared to a first threshold pressure value. In the case that the obtained pressure value is below the first threshold pressure value, the compressor(s) (3, 12) of the compressor unit (2) are controlled in order to reduce a suction pressure of the vapour compression system (1).

Abstract: The present disclosure provides a variable-frequency compressor with adaptive heating power control and a method for operating the same. According to an embodiment of the present disclosure, the variable-frequency compressor includes: a compression unit, for compressing a medium entering the variable-frequency compressor; a motor, including a stator and a rotor, for driving the compression unit; and a controller, configured to adaptively control a heating power of a winding of the stator according to information of the variable-frequency compressor.

Abstract: A hydraulic piston machine is described comprising a piston (1) having a hollow (2) secured by a wall (3) and an insert (4) arranged in the hollow. Such a machine should have a high efficiency at low costs. To this end the insert (4) comprises a section (29) which extends out of the hollow (2).