A system and method for a compressor includes a compressor connected to a condenser, a discharge line temperature sensor that outputs a discharge line temperature signal corresponding to a discharge line temperature of refrigerant leaving the compressor, and a control module connected to the discharge line temperature sensor. The control module determines a saturated condenser temperature, calculates a discharge superheat temperature based on the saturated condenser temperature and the discharge line temperature, and monitors a flood back condition of the compressor by comparing the discharge superheat temperature with a predetermined threshold. The control module increases a speed of the compressor when the discharge superheat temperature is less than or equal to the predetermined threshold.

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 for sizing at least two variable capacity screw compressors and a refrigeration chiller incorporating a variable capacity screw compressor are separately presented.

A compressor unit (2) for use in a refrigeration circuit, comprises at least two compressors (8, 10); and a common variable frequency drive (6), configured to be connected to a three phase grid voltage supply (4); each compressor (8, 10) having an inlet port (12) configured to be in refrigerant communication, via a suction line, with an outlet of an evaporator; an outlet port (14) configured to be in refrigerant communication, via a pressure line, to an inlet of a condenser; a compressor motor (18), particularly an alternating current induction motor, with a three phase supply line (32-1, 32-2); a power modulation means (24) for controlling the power of the compressor (8, 10) according to its load needs; wherein each compressor (8, 10) is switchable, independently from the respective other compressor(s) (8, 10), to be connected, during start-up and acceleration of the respective compressor (8, 10), to the common variable frequency drive (6), and to be connected, during rated-speed operation of the respective compressor (8, 10), to a common three phase grid voltage supply (4).

The present disclosure relates to an adaptive logic board that includes a signal sensing circuit configured to receive an input signal as an electrical current. The signal sensing circuit includes a plurality of resistors and a plurality of switches configured to electrically couple or electrically decouple the plurality of resistors from the signal sensing circuit, in which each switch of the plurality of switches corresponds to a corresponding resistor of the plurality of resistors. The adaptive logic board also includes a sensing unit that is configured to measure a voltage drop of the input signal across an active resistor of the plurality of resistors.

Provided is an air conditioner configured such that the inside of an indoor unit is dried while an increase in a humidity in a room is suppressed. The air conditioner of the present invention includes an outdoor unit and an indoor unit having an indoor heat exchanger and a decompression device. The indoor heat exchanger has a first heat exchange portion and a second heat exchange portion. The decompression device is connected to the first heat exchange portion and the second heat exchange portion. This air conditioner performs cooling operation or dehumidifying operation in which the first heat exchange portion and the second heat exchange portion function as evaporators and reheat dehumidifying operation in which the first heat exchange portion functions as a condenser and the second heat exchange portion functions as the evaporator. Moreover, water repelling treatment is performed for the second heat exchange portion

A regulation method for an inverter compressor in a refrigeration system including establishing a working area via limit values for evaporation temperatures, condensation temperatures, compressor speeds, maximum compression ratio, and maximum superheat value, and measuring working values of the compressor in terms of evaporation temperature, condensation temperature, and compression ratio. If the compressor operates outside the established working area, the method includes modifying the working parameters of the compressor by acting on elements to be selected among the compressor speed, the opening angle of the expansion valve, and a combination thereof. If the compressor does not go back to the working area within a certain time, the method includes stopping operation of the compressor and triggering an alarm.

Provided is a control device that performs protection control of a compressor without malfunction. The control device activates protection control on a compressor included in a refrigerant circuit based on a pressure value detected by a pressure sensor that is installed at a low-pressure side of the refrigerant circuit and a change over time of the pressure value.

In a motor driving apparatus including an inverter connectable to n motors (n being an integer not less than 2) each including a rotor having a permanent magnet, braking operation is performed on i (i being an integer from 1 to n1) of the n motors, and then braking operation is performed on j (j being an integer from 1 to ni) of the n motors other than the i motors. It is possible to reduce the risks of failure of the inverter and demagnetization of the motors due to overcurrent by reducing current flowing through the inverter and the motors when the braking operation is performed.

A driving device includes a connection switching unit to switch a connection state of coils between a first connection state and a second connection state in which a line voltage is lower than in the first connection state, a controller to control a motor and the connection switching unit, and a rotation speed detector to detect a rotation speed of the motor. When the connection state of the coils is the first connection state and the rotation speed detected by the rotation speed detector becomes higher than or equal to a first rotation speed, the controller causes the motor to rotate at a second rotation speed higher than the first rotation speed, and then causes the connection switching unit to switch the connection state of the coils from the first connection state to the second connection state.

A control method, a control device for starting an air conditioner, a storage medium, and an air conditioner are disclosed. The method includes the step of acquiring current temperature variation information of a weather in an environment of the air conditioner and current startup parameters of the air conditioner. The method further includes the step of controlling operation parameters of the air conditioner according to the current temperature variation information and the current startup parameters of the air conditioner.