摘要 |
<p>of the disclosure Motor monitor signal analysis system A magnetic field motor monitor has a signal analysis system comprising an analog-to-digital converter for taking instantaneous samples of the motor magnetic field at accurately determined and equally spaced times synchronised with the line frequency driving the motor, a plurality of separate memories, means for adding the current instantaneous sample value to or subtracting it from the contents of each separate memory, addition or subtraction taking place in dependence on which of the samples is being processed, and means for providing from the contents of the memories signals indicative of the amplitudes of respective harmonically related frequency components of the motor magnetic field.</p> |