Abstract: An oil mechanical vacuum pump, which is equipped with an electric motor comprises an electronic control device for supplying the electric motor with power. The electronic control device comprises a frequency converter for controlling the excitation frequency Fecc of the voltage signal SU by which the motor is powered as a function of at least one operating parameter of the pump and of at least one threshold value that can be modified depending on the operating conditions of the pump.

Abstract: A pressure sensor is a micro-electro-mechanical vibrating device, with a silicon substrate (15; 15?) onto which a single-layer or multilayer vibrating assembly (121; 221; 321) is formed. It comprises an electrode (21; 21?), which makes the assembly to oscillate relative to the substrate at the resonance frequency or at another known frequency, and a detector for detecting the actual frequency and/or amplitude of said oscillation. The actual frequency and/or amplitude are affected by the conditions, in particular the pressure, of the external environment and the variations of the frequency and amplitude with respect to the values set by the electrode is used to measure pressure variations in the surrounding environment.

Abstract: A pressure sensor is a micro-electro-mechanical vibrating device, with a silicon substrate (15; 15?) onto which a single-layer or multilayer vibrating assembly (121; 221; 321) is formed. It comprises an electrode (21; 21?), which makes the assembly to oscillate relative to the substrate at the resonance frequency or at another known frequency, and a detector for detecting the actual frequency and/or amplitude of said oscillation. The actual frequency and/or amplitude are affected by the conditions, in particular the pressure, of the external environment and the variations of the frequency and amplitude with respect to the values set by the electrode is used to measure pressure variations in the surrounding environment.

Abstract: The present invention concerns a vacuum pumping device comprising an oil mechanical vacuum pump, equipped with an electric motor, and an electronic control device for supplying said electric motor with power. The control device comprises means for controlling the excitation frequency Fecc of the voltage signal SU by which said motor is powered as a function of at least one operating parameter of the pump and of at least one threshold value that can be modified depending on the pump operating conditions.

Abstract: An improved electronic device allows for the feeding of an ion pump with a plurality of voltages that are changed as a function of the current drawn by the pump and therefore of the pressure value within the pump.

Abstract: An electronic device for feeding an ion pump with two different tensions and for improved measuring of the pressure in the pump, the two different tensions being a normal operating tension and a lower tension at which a correct measurement of the pressure can be made in a pressure range up to beyond 10.sup.-10 torr. through a transformer whose primary or secondary winding is divided into two sections that can be connected and separated by switches controlled by oscillator circuits. Alternatively feeding at two different tensions can be obtained by feeding to the primary winding of the transformer a pulsed tension having a rectangular wave form and a high frequency controlled by a field effect transistor having an isolated gate. A sampling and holding circuit permits the pressure to be measured only in the conditions of feeding at the lower tension.