ABSTRACT
Motor’s mechanical faults can be judged by measuring the radial acceleration or displacement, this paper adopts the method of measuring the radial acceleration.
3 SYSTEM DESIGN
Figure 1 displays the structure of the system, which is composed of host computer system and motor control module. Host computer communicates with the motor control module through the CAN communications card, and with VC6.0 software installed. The signals of three phase current, voltage and the motor temperature are converted to 0∼5 V voltage signals through the corresponding transmitter. The acceleration signal is got by the radial vibration signal after low-pass filter circuit. The AD converter inside MCU collects the corresponding signal. MCU judges the faults types according to the failure criterion algorithm, and implements status display, storage and protection action. Output circuit is the man-machine interface circuit and execution circuit of monitoring system, consisting of the trip circuit, sound and light alarm circuit and display circuit. Motor control module can be communicated with the host via CAN bus, receives commands by host computer and transfers the corresponding state-data to the host computer.[4]
4 HARDWARE CIRCUIT DESIGN
4.1 Vibration detection circuit
The system adopts a piezoelectric acceleration sensor HK9101-J. Acceleration output signal is obtained by vibration sensor output signal through a low-pass filter circuit and amplification circuit.
