Two Minute Tips  

Machine Train: Belts

Noah Bethel | Vice President-Product Development, PdMA Corporation

Continuing the focus on the machine train analysis tools of the Emax Current Demodulation technology, this tip discusses belts. A variety of issues can develop related to a belt or sheave and knowing what to look for may allow us to correct the problem before damage occurs. A defective belt, out of round sheave, or angular/axial misalignment of the sheaves will elevate belt related frequencies and can be seen on the current spectrum. Belt Frequency = 3.142 (D/L) X (RPM/60) where D is the diameter of the motor mounted pulley, L is the length of the belt, and RPM is the motor speed. Another easy way to identify the belt frequency is using a strobe light. Once you have identified belt frequency, the next step is to establish a band alarm around that frequency to support speed/load changes. Increases in the amplitude of belt frequency, or multiples of belt frequency can be trended for analysis.

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About the Author

Noah Bethel Vice President-Product Development, PdMA Corporation

Noah has over twenty-five years of broad operations and electrical systems maintenance experience in industrial, commercial, and military settings ranging from nuclear submarines to world class amusement parks. His experience includes high and low voltage, AC and DC, power generation, power distribution, motors, and motor controllers. Noah is currently in charge of product development for new and existing PdM technology at PdMA Corporation.

Noah is a graduate of the University of the State of New York and the Naval Nuclear Power School and Training Unit. He is a Certified Maintenance Reliability Professional, with field experience in motor circuit analysis, current signature, power analysis, thermography, vibration analysis, oil analysis and ultrasonic testing.