| 摘要 |
<p>A device for measuring the power output and input of an electric induction motor uses a vibration sensor and frequency analysis to measure the motor speed, and calculates the motor slip and output power from the motor speed and motor plate data. An accelerometer may be mounted on the motor casing and used to detect vibrations. The frequency spectrum of the vibrations includes peaks 2, 3 associated with the AC power supply and the motor rotation speed. Input power is derived from output power and efficiency, the efficiency being derived from motor supplier data or from data on similar types and sizes of motor. The vibration sensor also senses vibration due to the motor drive frequency, thus enabling the motor no load speed to be calculated. An embodiment of the invention applies sensors to a group of motors, and the sum of the input powers can be compared with the total input power for the motor group measured by conventional electrical means. The motor parameters can then be adjusted to minimise the difference between the electrical total power, and the sum of the individual motors under a range of load conditions.</p> |
