| 摘要 |
<p>A method and arrangement for measuring the rate of revolution of a vacuum pump rotor are esp. suitable for a turbomolecular vacuum pump driven by an electric motor with a coil and armature. They enable the partic. simple measurement of revolution rate. The pump drive motor is switched off for a short period during which the frequency of the alternating voltage induced in the coil by residual magnetism of the armature is measured by a conventional frequency counter (11). The coil of the electric motor is either connected to the voltage source (2) or to the counter (11) via a changeover switch (8) in the motor power line (3). At least two (5,6) of the three power line phases (4,5,6) are able to be connected to the counter.</p> |
