진동센서, 가속도센서, 가속도계 기본 & 용도 & 설치법(By Jack Peters-CTC)

Summary

Key Points

• Accelerometers are primarily used in machines with rolling element bearings to measure absolute transmitted vibration, typically mounted in vertical, horizontal (radial), and axial (load zone) directions. 1:29
• Key advantages include measuring casing and absolute vibration, integrability to velocity, ease of mounting, and a wide frequency response, while disadvantages involve poor performance on fluid film bearings due to damping and sensitivity to mounting conditions. 1:46
• The core of an accelerometer's construction features a PZT ceramic element that generates an electrical charge from shear mode vibration, which is then converted to a voltage by an integrated electronic piezoelectric (IEPE) circuit. 9:32
• Accelerometers provide two main outputs: a dynamic AC signal for vibration measurement (sensitivity, commonly 100mV/G) and a DC bias voltage (10-14V) used to monitor the sensor's electronic health. 10:00
• Proper calibration of sensitivity requires specialized shakers (stroke for low frequency, dynamic for high frequency), while bias voltage can be checked with a simple power supply and meter for troubleshooting. 10:49
• Various accelerometer types exist with different sensitivities (e.g., 10mV/G for harsh environments, 500mV/G for low amplitude) and dynamic ranges, with power supply voltage being critical to prevent signal clipping. 24:10
• Effective wiring is crucial, requiring shielded cables with the drain wire grounded at the data collection point to mitigate electrical noise and prevent ground loops. 25:58
• Mounting technique significantly impacts frequency response; stud mounting offers the best reliability and maximum frequency range, while methods like magnets or probe tips introduce mass and reduce stiffness, severely limiting usable frequency. 35:15
• Specific mounting considerations include precise spot facing for side-exit sensors, correct axis orientation for tri-axial sensors, and ensuring fin mounts rest on the motor casing for accurate readings. 43:06
• CTC offers an unconditional lifetime warranty for its labeled products, covering repair or replacement at no charge except for shipping costs. 48:19