Electrical Troubleshooting Quiz — Feb. 4, 2020
Last summer, the air conditioning at a manufacturing plant could not keep up. You work for an electrical services firm that this company contacted for help. They want a diagnosis and treatment plan they can implement over the winter. Your boss put you in charge of the troubleshooting.
The plant consists of four manufacturing buildings and an administrative building, all of which experienced issues. The HVAC system uses roof-mounted chillers and there are 32 of them in total. Six of these needed a motor replacement last year, and when you investigated further you found the plant replaces at least a couple of chiller motors each year.
What are some issues you should investigate?
The first issue to look at is not even electrical. If the units cannot keep up and motors are burning up, that's a sign of excessive load. A primary cause in these kinds of systems is a unit/roof-curb mismatch; bring in an expert to verify the units and ductwork match and the ductwork doesn't leak.
Next, look at the motor failures of the plant air system. If the rate is also high, then you probably have plant-wide problems with power quality, bonding deficiencies, motor maintenance, or any combination thereof. If the rate is low, that's a good indicator these issues are not plant-wide; focus your investigation for them on the HVAC system.
Try to find any evidence that condenser coils were icing up. A big clue that they probably were is the existence of easily accessible thermostats. If non-maintenance employees lowered thermostat settings, this would explain the icing and motor burnout.
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.