A refrigerant compressor includes an electric motor. A current sensor measures current flow to the electric motor. A switching device is configured to close and open to allow and prevent current flow to the electric motor, respectively. A maximum continuous current (MCC) device includes a stored digital value corresponding to a maximum continuous current for the electric motor. A motor protection module: communicates with the MCC device, the current sensor, and the switching device; determines a first MCC for the electric motor as a function of the stored digital value received from the MCC device; selectively sets a predetermined MCC to the first MCC; and controls the switching device based on a comparison of the current flow to the electric motor and the predetermined MCC.

A fault-rectification method for an eccentric screw pump of a conveying apparatus for conveying viscous construction materials, comprising the steps of monitoring a start of a conveying operation of the eccentric screw pump by way of a characteristic-variable-monitoring program of a control device of the conveying apparatus, wherein a working-free program is executed by the control device of the eccentric screw pump if, for one or more characteristic variables. The characteristic-variable-monitoring program acquires characteristic-variable values which are stored, alone or in combination with one another, as fault values that indicate jamming of a rotor/stator unit of the eccentric screw pump, and wherein otherwise a conveying operation is begun. The eccentric screw pump is operated in the working-free program in such a way that an electric motor of a drive unit of the conveying apparatus is multiply alternately switched on and switched off.

The invention pertains to a method for predicting a failure in the rotation of the rotor of a vacuum pump, comprising the following steps: sequences of events related to the change over time of the vacuum pump functional signals are recorded (101), a match is sought between at least one sequence of events and at least one pre-established association rule precursory pattern of a vacuum pump behavior model within the recorded sequences of events, said pre-established association rule's precursory patterns involving a failure in the rotor rotation (102), and a time prediction window is deduced during which a failure in the rotor rotation will occur in a vacuum pump (103). The invention also pertains to a pumping device comprising: a vacuum pump (7) comprising at least one rotor and one pump body, said rotor having the potential to be driven rotationally within said pump body by a motor of said pump (7), a functional signal sensor (9) of said pump (7), and a means of predicting (10) a time prediction window during which a failure in the rotor rotation will occur in the vacuum pump (7), said means for prediction (10) calculating the predictive time window based on measurements provided by said functional signal sensor (9).

A screw compressor includes: a containment body including: a suction chamber and a suction port for a fluid to be compressed; a delivery chamber and a discharge port for the compressed fluid; a containment seat for two helical compression rotors; two helical compression rotors; an electric motor to actuate the helical compression rotors; lubrication for the helical compression rotors; filtration of the compressed fluid; an inverter connected to the electric motor; an electronic control unit configured to control the inverter; a low-pressure sensor located at the suction port and connected to the electronic control unit; a high-pressure sensor located at the discharge port and connected to the electronic control unit; an adjustment spool configured for adjusting the width of an outlet opening from the compression rotor chamber; a fluid actuator to move the adjustment spool; a current meter that measures the electric current absorbed by the electric motor.

A screw compressor includes: a containment body including: a suction chamber and a suction port for a fluid to be compressed; a delivery chamber and a discharge port for the compressed fluid; a containment seat for two helical compression rotors; two helical compression rotors; an electric motor to actuate the helical compression rotors; lubrication for the helical compression rotors; filtration of the compressed fluid; an inverter connected to the electric motor; an electronic control unit configured to control the inverter; a low-pressure sensor located at the suction port and connected to the electronic control unit; a high-pressure sensor located at the discharge port and connected to the electronic control unit; an adjustment spool configured for adjusting the width of an outlet opening from the compression rotor chamber; a fluid actuator to move the adjustment spool; a current meter that measures the electric current absorbed by the electric motor.