Embodiments of the present disclosure relate to a refrigeration system that includes a compressor configured to circulate refrigerant along a refrigerant loop, a motor configured to drive the compressor, and a variable speed drive coupled to the motor and configured to supply power to the motor. The variable speed drive includes a primary winding of a step down transformer coupled to an alternating current (AC) power source, a first secondary winding of the step down transformer, where the first secondary winding is configured to supply power at a variable supplied voltage to the motor when the motor operates below a threshold voltage, and a second secondary winding of the step down transformer, where the second secondary winding is configured to supply power at a fixed supplied voltage when the motor operates at or above the threshold voltage.

A motor driving device is a device for driving a motor including stator windings, includes: a connection switching unit that is connected to the stator windings, includes circuits including semiconductor switches, and switches connection condition of the stator windings to either of first connection condition and second connection condition different from the first connection condition by setting the semiconductor switches to ON or OFF; and an inverter that supplies AC drive voltages to the stator windings.

A refrigerating cycle device includes a compressor, a motor, and a wiring switch part. The compressor compresses a refrigerant. The motor generates power for compressing the refrigerant by rotating a rotor with voltage applied to a plurality of wirings. The motor is disposed in the compressor. The wiring switch part switches between a plurality of wiring states by changing connection between the plurality of wirings. When a rotational speed of the rotor exceeds a predetermined value, the wiring switch part switches to a first wiring state of the plurality of wiring states. The first wiring state differs from a second wiring state of the plurality of wiring state. Efficiency of the second wiring state is highest at the rotational speed.

Proposed is a method of controlling a gas heat-pump system, the system including an air conditioning module having a compressor and indoor and outdoor heat exchangers, and an engine module having an engine combusting mixed gas and thus generating drive power for operating the compressor, the method including: measuring factors that are temperature and humidity of outside air, an rpm of the engine, intake pressure, and an air-fuel ratio, the factors having effects on driving of the engine in an operating environment where the engine is driven; measuring a necessary ignition voltage for an ignition coil in a manner that corresponds to at least one of a plurality of the measured factors; and calculating a dwell time at which the necessary ignition voltage is output by the ignition coil.

A system for controlling a capacity of a compressor includes a motor of the compressor including a main winding connected at a connection point to an auxiliary winding and a drive configured to control a speed of the motor. The system includes a first switch configured to selectively connect the main winding to either a first line voltage or a first output of the drive, a second switch configured to selectively connect the connection point to either a second line voltage or a second output of the drive, and a third switch configured to selectively connect the auxiliary winding to either a capacitor or a third output of the drive. The system includes a solenoid valve configured to selectively either operate in a first capacity or a second capacity. The system includes a control module configured to control the drive, the first switch, the second switch, and the third switch.

A driving device includes an inverter to output a voltage to coils, a connection switching unit to switch a connection state of the coils between a Y connection and a delta connection, and a controller. The controller causes the inverter to stop outputting, when the connection state of the coils is the Y connection and a current value of the inverter reaches a first threshold A, or when the connection state of the coils is the delta connection and the current value of the inverter reaches a second threshold B. The first threshold A and the second threshold B satisfy B<√3×A.

A stator includes a yoke portion, and a tooth portion located inside the yoke portion in a radial direction. A fracture surface ratio of an inner surface of the tooth portion in the radial direction is lower than a fracture surface ratio of a side surface of the yoke portion.

A recreational vehicle air conditioning system supports multiple recreational vehicle air conditioning units having closed air conditioning circuits and a controller that is electronically coupled to each of the recreational vehicle air conditioning units to control each of the closed air conditioning circuits to regulate an overall power consumption of the multiple recreational vehicle air conditioning units. A recreational vehicle air conditioning system may also support multiple recreational vehicle air conditioning units where a refrigerant line set is coupled between the recreational vehicle air conditioning units such that a compressor in one of the recreational vehicle air conditioning units is capable of supplying refrigerant to the evaporators of the multiple recreational vehicle air conditioning units, and such that valves coupled in series with each of the evaporators may be regulated to control cooling by each recreational vehicle air conditioning unit.

A variable capacity screw compressor comprises a suction port, at least two screw rotors and a discharge port being configured in relation to a selected rotational speed that operates at least one screw rotor at an optimum peripheral velocity that is independent of a peripheral velocity of the at least one screw rotor at a synchronous motor rotational speed for a rated screw compressor capacity. A motor is configured to drive the at least one screw rotor at a rotational speed at a full-load capacity that is substantially greater than the synchronous motor rotational speed at the rated screw compressor capacity. A variable speed drive receives a command signal from a controller and generates a control signal that drives the motor at the selected rotational speed.

A method of feedthrough and overcurrent protection of a sealed compressor used in a transport climate control system (“TCCS”) is provided. The TCCS includes a climate control circuit with a sealed compressor. The sealed compressor includes an outer housing and an electrical motor within the outer housing. The method includes operating the sealed compressor to compress a working fluid by supplying electrical power to the electric motor of the sealed compressor via a sealed electrical feedthrough in the outer housing of the sealed compressor. The method also includes detecting an operating parameter of the sealed electrical feedthrough, and determining whether the sealed electrical feedthrough is in a melting condition based on the detected operating parameter. Also, the method includes adjusting operation of the climate control circuit upon determining that the sealed electrical feedthrough is in the melting condition until the sealed electrical feedthrough is no longer in the melting condition.