A motor includes a stator core having an annular shape, a coil wound around a tooth of the stator core, a first terminal electrically connected to the coil, a housing that houses the first terminal, and a second terminal at least partially inserted into the first terminal housed in the housing. The second terminal includes an electrical connecting portion inserted into the first terminal and electrically connected to the first terminal. The housing includes a first restricting portion that restricts movement, in a circumferential direction of the stator core, of a portion of the second terminal other than the electrical connecting portion.

A rotary-machine control device includes: a connection switching device switching a connection state of stator windings of a rotary machine; a current detection unit detecting a rotary machine current flowing in the rotary machine; a voltage application unit applying voltage to the rotary machine; a control unit generating a voltage command provided to the voltage application unit and outputting a switching command to switch the connection state to the connection switching device; and an open-phase determination unit determining presence or absence of disconnection in the rotary machine or presence or absence of disconnection of a power distribution line to the rotary machine. During rotation of the rotary machine, the control unit outputs the switching command and the open-phase determination unit determines presence or absence of disconnection.

The integrated expander and motor-compressor assembly comprises a compression section mounted between the two radial bearings on a trans-mission shaft, an expander cantilevered at a free end of the transmission shaft, a gas diffuser and a duct between the expander and a first radial bearing, the first radial bearing been the closest radial bearing to the expander. The gas diffuser diffuses a gas barrier which is sucked up by the duct.

A plurality of scroll compressors with different fixed volume indexes are connected in fluid parallel circuit and configured to selectively operate to maximize isentropic efficiency at different condensing temperatures. Different quantities of scroll compressors of different volume indexes may be selected based upon typical climate or geographic location environmental conditions to attempt to maximize efficiency. A controller may selectively operate different combinations of the compressors of different volume indexes bases up load demands and condensing temperature conditions, which may be determined in a variety of ways.

An inverter for driving a motor that has a switchable connection of windings and drives a load element having a periodically varying load torque is provided. The inverter is controlled so that an output torque of the motor follows the periodic variation of the load torque. The inverter is controlled so that a current flowing through the motor is zero during a period including a minimum torque phase at which the load torque is at or near a minimum value. The connection is switched while the current flowing through the motor is zero. It is possible to switch the connection of the windings while the motor is rotating, and avoid an increase in apparatus size.

A core includes a laminated body. The laminated body includes a plurality of electrical steel sheets stacked one on another. The laminated body includes a contact area between a pair of adjacent electrical steel sheets of the plurality of electrical steel sheets. The contact area includes a first friction area and a second friction area with friction coefficients different from each other.

A refrigerant circuit includes a first compressor connected to a first suction pipe and a first discharge pipe and configured to compress a refrigerant, a second compressor connected to a second suction pipe and a second discharge pipe and configured to compress the refrigerant discharged from the first compressor, a radiator, and a high-pressure passage connecting the second discharge pipe and the radiator. A first oil drain passage guides an oil in the second compressor to one of the first suction pipe and an intermediate port of the first compressor, without via the high-pressure passage.

In a hermetic refrigerant compressor, a thrust bearing (e.g., thrust ball bearing (210)) is provided on a thrust surface (136) of a main bearing (134). One end of a sliding surface of the main bearing (134), the one end being closer to a compression chamber (133) than an opposite end of the sliding surface, is a first end, and the opposite end of the sliding surface is a second end. A distance between a center axis of the compression chamber (133) and the second end of the sliding surface (sliding surface lower end (139)) of the main bearing (134) is a distance L, and a distance between the center axis of the compression chamber (133) and the first end of the sliding surface (sliding surface upper end (138)) of the main bearing (134) is a distance La. When the distance L is in a range of 38 mm to 51 mm, the distance La is less than or equal to 16 mm.

A system includes a dynamic compressor and a controller having a processor and a memory. The compressor includes a first compressor stage having a first variable inlet guide vane (VIGV) and a second compressor stage having a second VIGV. The memory stores instructions that program the processor to operate the compressor at a current speed, a first position of the first VIGV, and a second position of the second VIGV to compress the working fluid, and to determine if a condition is satisfied. If the condition is not satisfied, the processor is programmed to continue to operate the compressor at the current speed, the first position of the first VIGV, and the second position of the second VIGV. If the condition is satisfied, the processor is programmed to change the second position of the second VIGV to a third position and maintain the first position of the first VIGV.

According to one embodiment, a refrigeration cycle apparatus includes a motor which including a plurality of phase windings in a mutually unconnected state, a first inverter which controls application of electric power to one ends of the phase windings, a second inverter which controls application of electric power to the other ends of the phase windings, switches connected between the other ends of the phase windings, and a motor controller which selectively sets one of an open-windings mode and a star-connection mode. The motor controller sets, at the time of startup of the motor, the open-windings mode.