Counterfeit bearings use another brand’s name when that brand didn’t make it.

Between fiscal year 2012 and fiscal year 2016, U.S. Customs and Border Protection has seized counterfeit bearing products through numerous entry ports. The World Bearing Association (WBA) and individual members of the WBA raided suspected Chinese facilities and found MILLIONS of counterfeit products since 2009.

Counterfeits are found in all sectors and detection is difficult.

• Counterfeiters are getting better
• Authentication is becoming more challenging

However, each authentic brand has unique overt/covert features and brand owners have designated experts assigned to authentication. ALWAYS contact the manufacturer.  The best way to safeguard product authenticity is to source products through authorized sources. To watch a presentation on this subject, click here. 

You have heard us many times discussing the effectiveness of an In-Rush/Start-Up test as a critical piece of information in assessing a variety of potential anomalies in components such as the stator, rotor, power, and load. Capturing the In-Rush/Start-Up during the start of an electric motor allows the capture of data when the motor is under extreme stress and more likely to expose anomalies.

Less often discussed is that the In-Rush/Start-Up test can also be instrumental in identifying mechanical and load related defects during routine scheduled testing. The enveloping feature of the In-Rush/Start-Up test taken during steady state gives a direct look into the load fluctuations of the motor being tested. Having a baseline of the expected load characteristics for a motor provides a very easy comparison for early identification of even subtle changes in these load characteristics which could be early indications of developing faults.

To view examples of these tests and see them successfully applied in the identification of a developing pump failure visit our website case study at:  http://www.pdma.com/webinars/Pump_Case_Study/Pump_Case_Study.mp4

The CL-Profiler is the perfect solution for profiling slip ring assemblies and commutators.

This tool can be used during the repair process and also in the field during DC motor PM’s in order to have a baseline; or, as a troubleshooting tool for aggravated commutator and brush wear. It can also be used annually in order to check for trending for commutator looseness, wear, vibration, and contamination influences.

In an AC Induction motor the rotor turns slower than the rotating magnetic field in the stator. This differential rotation loosely referred to as slip can be easily seen in a current spectrum by an elevated pole pass frequency (Fp) peak equal to the number of poles times the slip. The basic analysis concept is to use the amplitude variations of this peak to identify and trend defects in the rotor condition. The higher the amplitude of the Fp, the higher the severity of a possible rotor defect. However, it is important to remember that rotor condition is not the only thing that can affect the Fp amplitude. Machine train load fluctuations can often match the Fp creating a false indication of a rotor anomaly through an elevated Fp. An easy way to isolate the elevated Fp to either a mechanical or electrical source is to evaluate the 5th harmonic frequency peak in the same current spectrum. The 5th harmonic is not fooled by a mechanical load fluctuation and can greatly increase the confidence of the analyst in making the right call on a possible rotor anomaly.

To see more details on the 5th harmonic and other rotor analysis techniques visit the PdMA YouTube channel at:
https://www.youtube.com/watch?v=P4XIYg-695A&list=PLjgXwy4LaY3rMI2MNKer7SxDA50n9LMSa&index=6

Your motor fails to start. What immediate actions do you take when a motor trips on start-up? From a reliability standpoint a variety of possibilities and questions come to mind that may help you decide which direction to take. Was it an instantaneous trip on In-Rush or a time delay trip later in the Start-Up? If instantaneous, is it a stator fault or a nuisance trip? If it’s a delayed trip, is it load driven or a rotor anomaly? Oh, and how many times did the operator try to start the motor? Just clamping on an ammeter to see what the current reading is when it trips will not give you the whole story. Looking at the trend of your RMS envelop current signal and comparing it to the raw time domain of the current is ideal.Access to these values and plots, along with previously recorded In-Rush/Start-Up tests will give you the information necessary to make the right decisions for a quick return to productivity.

To see a detailed case study on a critical motor failing to start go to:https://www.youtube.com/watch?v=fMDbhdLDu4o