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Motor repair answers: Virtual Training Trends on motors and drives were covered in the CFE Media & Technology Virtual Training Day on Aug. 19, providing online training; the instructor for one of the courses answered additional questions about motor repairs. Four courses offer potential for four approved learning units:
a popular misconception is that motor design life has also increased. However, the factors that affect motor thermal life, such as winding temperature, for the most part haven’t changed; and the bearings and mechanical systems are still the same.
Can you share a useful “detective story” about motor repairs?
• What to know when repairing electric motors • How to specify motors for more efficient HVAC systems • Introduction to motors and drives • How to design hospital, health care facility HVAC systems.
Motor repair application, motor designs, motor detective stories
Thomas Bishop, PE, senior technical support specialist, EASA, gave 45 minutes of instruction on motor repairs followed by more than 15 minutes of questions and answers. The information will be available at www.controleng.com/online-courses until Nov. 30, 2020. Answers to unanswered questions follow.
Are there certain applications that have particular motor repair concerns?
Applications with higher than normal mechanical stress or in harsh environments may require additional repair steps. For applications with higher stress, such as a rock crusher, mechanical components such as the shaft need closer inspection to check for bending or cracks. Harsh environments such as outdoors near the ocean with its salt water can lead to extensive corrosion damage. Applying overcoating with epoxy materials would probably be called for to reduce the effects of corrosion.
Do more recent motor designs extend motor life over earlier generations? How?
The short answer is “no.” As energy efficiency of motors has increased,
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Thomas Bishop, PE, is senior technical support specialist, EASA. He offered information about motor repairs in a Aug. 19 one-hour course available for viewing until end of November 2020. Courtesy: CFE Media and Technology and EASA
An end user had a motor in a centrifugal pump application and when it required service center repairs, it was found the shaft had a crack in it. The pump application would not have caused a mechanical shock that could explain the cracked shaft, and the next suspicion was the shaft material had an inherent flaw in it. A root cause analysis (RCA) was performed and what was found was the motor had been used in a severe mechanical shock application, a shredder subject to overload, and that the crack occurred in that prior application. ce
IIoT platform built on battery-free sensors
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any analysts have predicted an explosion in the number of Industrial Internet of Things (IIoT) devices that will come online over the next decade. Sensors play a big role in those forecasts. Unfortunately, sensors come with their own drawbacks, many of which are due to the limited energy supply and finite lifetime of their batteries. A sensor to monitor Everactive, a startup company founded rotating machinery, like by MIT graduates, has developed industrial sensors that run around the clock, motors and pumps, runs require minimal maintenance, and can last on second-generation over 20 years. The company created the battery-free chips. sensors not by redesigning its batteries, but by eliminating them altogether. Everactive builds finished products on top of its chips that customers can quickly deploy in large numbers. Its first product monitors steam traps, which release condensate out of steam systems. Such systems are used in a variety of industries, and Everactive’s customers include companies in sectors like oil and gas, paper, and food production. Everactive has also developed a sensor to monitor rotating machinery, like motors and pumps, that runs on the second generation of its battery-free chips. - Zach Winn, Massachusetts Institute of Technology (MIT).
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control engineering
September 2020
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