Electrical Troubleshooting Quiz — Sept. 21, 2021
You’ve received a complaint about a particular production machine. The production supervisor meets you at the machine to discuss what’s going on. The problem is it won’t always start. A sign is posted that says to wait 5 min. between starting attempts to prevent burning out the drive motor. It often takes three tries, which wastes 15 min. of the operator’s time and costs 15 min. of production time.
The supervisor would be fine with needing a second attempt on rare occasions, but the team can’t be wasting 15 min. every day.
They’ve already implemented a pre-start check to ensure no parts are in the system when a start attempt is made. Once the motor starts, everything works fine, so that rules out any gross misalignment, parts jams, etc. How can you solve this?
It almost sounds like the motor needs to warm up because it starts eventually. Perhaps simply allowing two attempts before a 5-min. wait will fix the time waste issue; measure the motor temperature before trying.
Perhaps the wrong grease is being used or the motor is overgreased. Determine the correct lubricant, and use the recommended procedure to lubricate the motor properly. Apply the same logic to the gearbox, which might be using the wrong gear oil. Replacing older paraben-based oils with synthetic oils in both places will eliminate several issues that may contribute to this problem.
Or perhaps the motor is the wrong one for the application. It might be an incorrect NEMA design or the wrong size. It might also be defective. To find out, test the motor to see how much starting current it needs while uncoupled from the load.
About the Author
Mark Lamendola
Mark is an expert in maintenance management, having racked up an impressive track record during his time working in the field. He also has extensive knowledge of, and practical expertise with, the National Electrical Code (NEC). Through his consulting business, he provides articles and training materials on electrical topics, specializing in making difficult subjects easy to understand and focusing on the practical aspects of electrical work.
Prior to starting his own business, Mark served as the Technical Editor on EC&M for six years, worked three years in nuclear maintenance, six years as a contract project engineer/project manager, three years as a systems engineer, and three years in plant maintenance management.
Mark earned an AAS degree from Rock Valley College, a BSEET from Columbia Pacific University, and an MBA from Lake Erie College. He’s also completed several related certifications over the years and even was formerly licensed as a Master Electrician. He is a Senior Member of the IEEE and past Chairman of the Kansas City Chapters of both the IEEE and the IEEE Computer Society. Mark also served as the program director for, a board member of, and webmaster of, the Midwest Chapter of the 7x24 Exchange. He has also held memberships with the following organizations: NETA, NFPA, International Association of Webmasters, and Institute of Certified Professional Managers.