DC Motor Broken Coupling and Faulty Fuses Diagnosis with Ultrasound
SDT Ultrasound Solutions technicians used ultrasound and vibration analysis to diagnose a broken coupling and four faulty fuses on a DC motor. The analysis revealed impacting at the coupling and fluctuations in motor run speed due to faulty firing cards.
By using both hashtag#Ultrasound & hashtag#VibrationAnalysis, SDT Ultrasound Solutions hashtag#ConditionMonitoring Techs were able to fully diagnose everything wrong with this DC Motor connected to a Fan Pump!
In FIGURE 1, we can see initial readings recorded on this assets coupling. As you can probably tell, this coupling is in very bad shape, with lots of impacting at its regular run speed.
FIGURE 2 looks at the Ultrasound Spectra of this coupling. The periodic cursers do not line up with the impacts, indicating fluctuations in motor run speed.
When firing card fails, one third of the power to the asset is lost, resulting in momentary rotational speed changes. This will lead to high amplitudes at 1/3X and 2/3X SCR frequencies.
As seen in the vibration measurements in FIGURE 3, this motor was firing at 1/3X SCR which is 7200 CPM - this indicated to the discovering technician that two thirds of the firing cards were faulty.
Using two condition monitoring technologies, members of the SDT Ultrasound Solutions Service Team were able to diagnose a broken coupling using ultrasound and four out of six blown fuses on a DC motor using Vibration.
hashtag#Reliability hashtag#Ultrasound hashtag#HearMore hashtag#FoundWithSound
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This defect was found by: Gilles Lanthier