conveyor — vibration_health (accelerometer-gearbox)
Physics
Section titled “Physics”A conveyor drive’s gearbox and motor bearings generate broadband vibration whose velocity RMS (10-1000 Hz, per ISO 20816-3) tracks overall mechanical condition, with narrowband content at 1x/2x running speed (imbalance/misalignment) and at bearing defect frequencies (BPFO/BPFI/BSF/FTF) pointing to specific developing faults; a gearbox additionally shows gear-mesh frequency (tooth count x shaft speed) and its sidebands when tooth wear or misalignment develops. An accelerometer on the gearbox or motor bearing housing is sampled well above 2x the highest frequency of interest: at a typical low-speed conveyor drive (motor running near 1800 RPM = 30 Hz, reduced through a gearbox to a much slower belt speed), the gear-mesh and bearing-defect frequencies of interest stay under a few hundred Hz, so a 4000 Hz acquisition rate gives ample margin; the edge node reduces this to 1 Hz velocity-RMS and order features for the historian rather than streaming raw waveform continuously. This recipe uses a flexible-support default because many conveyor drive units are mounted on a fabricated steel stand or frame rather than bolted to a rigid concrete/machine-bed foundation, which is the more conservative (more alarm-sensitive) choice; a drive bolted directly to a rigid structural base should instead be configured rigid.
Sensor
Section titled “Sensor”- Spec: piezoelectric accelerometer, IEPE/4-20mA output, 0.5-5 kHz bandwidth, stud or magnetic mount
- Signal: scalar (mm/s), range n/a
Example parts
Section titled “Example parts”- Banner Engineering QM30VT1 vibration/temperature sensor (velocity RMS + bearing temperature)
- ifm electronic VSA001 vibration sensor (acceleration/velocity 4-20 mA output)
- Pepperl+Fuchs VIS-M18-AI-KH1 M18 vibration sensor
Mounting
Section titled “Mounting”Stud-mount or magnetic-mount the accelerometer on the gearbox output-shaft bearing housing (or on the motor’s outboard bearing housing if the gearbox lacks an accessible flat surface), radially, on a clean unpainted surface. Avoid mounting on guards or covers that are not rigidly fastened to the gearbox/motor casting, since a flexible intermediate structure attenuates the high-frequency signal before it reaches the sensor.
Wiring
Section titled “Wiring”2-wire shielded IEPE cable (or 4-20 mA analog for a current-loop variant) to a vibration input module on the edge box, routed along the conveyor drive’s existing cable tray away from motor power and VFD cabling to avoid electrical noise pickup.
Validation
Section titled “Validation”with the conveyor running loaded at normal belt speed, compare the detector’s velocity-RMS against a handheld calibrated vibration meter at the same point on the gearbox/motor bearing housing
Expected: detector velocity-RMS within +/-10% of the handheld meter reading, and the reported ISO 20816 zone matches the zone the handheld reading falls into for the configured iso_group/support
Safety notes
Section titled “Safety notes”- lock out the conveyor drive motor starter (LOTO) before working near the gearbox or motor bearing housing to install the sensor
- keep hands and tools clear of the belt, pulleys, and drive coupling at all times; a conveyor can be re-energized remotely or by another operator if LOTO is not verified
- route and secure the sensor cable away from the belt and any pinch points so it cannot be drawn into moving parts
150–650 USD, difficulty 3/5, ~30 min install downtime.