Electrical Troubleshooting Quiz — June 5, 2018
Six months ago, a new production line was installed. Under the company's new cost-cutting program, a three-bid system awarded the electrical work to a firm whose bid was far lower than that of the firm the plant had been using for years. The system has been buggy ever since.
The plant manager wants you to figure out what’s wrong. To help you get started, he gave you a report generated by the computerized maintenance management system (CMMS). This report is based on the reason code entered for each maintenance call. These failures have the highest incident rate:
- Dead circuit board.
- Malfunctioning controller.
- Operator screen failure.
- Electric shock to personnel.
- Random shutdown, no cause identified.
- Gearbox bearings failed.
- Motor bearings failed.
How might you get to the bottom of this?
It is rare that a company ever saves money by going with a lowball bidder. In this case, the company has paid dearly for that. Clearly, many shortcuts were taken to come in at that lowball price.
The failures with the highest incidence rate point toward bonding deficiencies. Your equipment grounding conductor (EGC) and the bonding jumpers that connect to it provide a ground-fault current path and connect normally non-current carrying metal parts of equipment. A methodical inspection will reveal many deficiencies; fix those, and your failure rate will drop dramatically.
Then turn your attention to workmanship issues. Start with thermographic scans of connections. Conduct Ohmic measurements across suspect connections; repair bad ones.
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.