A variable speed drive (VSD) can be used to vary the voltage-to-frequency ratio (V/f) supplied to a compressor motor of a heating, ventilation, air conditioning or refrigeration (HVAC&R) system to make the motor stronger or weaker to compensate for varying conditions in the HVAC&R system. The VSD and corresponding control system or algorithm can monitor an operating parameter of the HVAC&R system, such as the kW absorbed by the motor, and then raise or lower the V/f of the VSD to obtain the lowest possible power consumption from the motor.

A variable speed drive (VSD) can be used to vary the voltage-to-frequency ratio (V/f) supplied to a compressor motor of a heating, ventilation, air conditioning or refrigeration (HVAC&R) system to make the motor stronger or weaker to compensate for varying conditions in the HVAC&R system. The VSD and corresponding control system or algorithm can monitor an operating parameter of the HVAC&R system, such as the kW absorbed by the motor, and then raise or lower the V/f of the VSD to obtain the lowest possible power consumption from the motor.

A variable speed compressor includes a housing assembly having a suction port and an inlet port, a motor disposed within the housing assembly, and at least one rotatable element mounted within the housing assembly. The at least one rotatable element is driven by the motor about an axis of rotation. The variable speed compression additionally includes an unloading system having at least one valve. The unloading system is selectively operable to supplement an unloading of the variable speed compressor defined by an operational speed of the variable speed compressor.

Positive displacement machine such as a compressor, expander, pump or the like, for displacing a gaseous or liquid medium, the machine containing an element with at least one inlet and at least one outlet for the medium and at least two cooperating driven moving parts. The mutual periodic movement of the moving parts displaces the medium from the inlet to the outlet. Each of the at least two driven cooperating moving parts is provided with its own individual drive. The element is provided with a kinematic synchronisation coupling between the at least two cooperating moving parts for the mutual kinematic synchronisation of their movements.

A processing chamber is connected to a lock chamber. For evacuating the lock chamber and/or the processing chamber a vacuum pump system is provided. The latter comprises a vacuum pump equipment having at least one vacuum pump. Further, the vacuum pump system comprises a valve device for connection to the lock chamber as well as a controller. For noise reduction, a cyclically occurring operating parameter is determined by means of the controller. From said parameter it is determined at which point in time the valve is opened such that temporally before the opening of the valve the rotational speed of at least one of the vacuum pumps can be reduced. This results in a considerable noise reduction at continuing good pump-out times.

A processing chamber is connected to a lock chamber. For evacuating the lock chamber and/or the processing chamber a vacuum pump system is provided. The latter comprises a vacuum pump equipment having at least one vacuum pump. Further, the vacuum pump system comprises a valve device for connection to the lock chamber as well as a controller. For noise reduction, a cyclically occurring operating parameter is determined by means of the controller. From said parameter it is determined at which point in time the valve is opened such that temporally before the opening of the valve the rotational speed of at least one of the vacuum pumps can be reduced. This results in a considerable noise reduction at continuing good pump-out times.

The invention relates to a method used to control a scroll compressor having a first and a second spiral, in particular that are arranged one inside the other. The first spiral can be moved by a motor relative to the second spiral for a decompression or compression operation of the scroll compressor. The invention reduces vibration (actual acceleration forces) in the scroll compressor to allow for a longer service life by adapting a torque curve of the motor on the basis of measured acceleration forces on the scroll compressor which, in turn, is based on the position and/or positional angle of the first spiral relative to the second spiral such that the acceleration forces are reduced below a threshold or minimized.

The invention relates to a method used to control a scroll compressor having a first and a second spiral, in particular that are arranged one inside the other. The first spiral can be moved by a motor relative to the second spiral for a decompression or compression operation of the scroll compressor. The invention reduces vibration (actual acceleration forces) in the scroll compressor to allow for a longer service life by adapting a torque curve of the motor on the basis of measured acceleration forces on the scroll compressor which, in turn, is based on the position and/or positional angle of the first spiral relative to the second spiral such that the acceleration forces are reduced below a threshold or minimized.

The invention relates to a method for controlling a rotary screw compressor, having at least a first and a second air-end, wherein both air-ends are driven separately from one another and speed controlled. According to the invention, the following steps are carried out: detection of a volume flow taken at the outlet of the second air-end; adjustment of the rotational speed of both air-ends, when the removed volume flow fluctuates in a range between a maximum value and a minimum value; opening of a pressure-relief valve, if the volume flow falls below the minimum value; and reduction of the rotational speed of at least the first air-end to a predetermined idling speed (V1.sub.L) to reduce the volumetric flow delivered by the first to the second air-end.

The invention relates to a method for controlling a rotary screw compressor, having at least a first and a second air-end, wherein both air-ends are driven separately from one another and speed controlled. According to the invention, the following steps are carried out: detection of a volume flow taken at the outlet of the second air-end; adjustment of the rotational speed of both air-ends, when the removed volume flow fluctuates in a range between a maximum value and a minimum value; opening of a pressure-relief valve, if the volume flow falls below the minimum value; and reduction of the rotational speed of at least the first air-end to a predetermined idling speed (V1.sub.L) to reduce the volumetric flow delivered by the first to the second air-end.