Electrical Troubleshooting Quiz — March 5, 2019
The plant has a custom-built, multi-stage production machine. Each stage is a modified machine that formerly served some other purpose; “recycling” made this system affordable.
Some stages require operator input, others do not. For example, the operator loads metal blocks into a multi-position drilling/chamfering machine but a robotic arm moves the drilled/chamfered parts to a multi-position buffing machine. A programmable logic controller (PLC) controls the flow of plastic pellets into another stage.
Lately, the scrap rate has been unacceptably high (finished parts don’t meet specs). Three different techs have run through the manufacturer’s maintenance and calibration procedure and no adjustments were needed. How might you address this?
A good first step is to audit the operators. Identify where in the process the out of spec operations are occurring and observe the operators at (and upstream of) each “where.” Are they following the manufacturer’s procedure? Make videos of each operator and each station.
Characterize the failure modes (give each one a name, for example “over-chamfer”) and compile a spreadsheet showing the number of instances of each. Submit this information, along with scrap part photos and the videos taken earlier, to the manufacturer for technical and troubleshooting assistance.
A machine problem could be caused by any of several factors, such as:
- Inadequate vibration protection. Install vibration sensors.
- Power quality problems. Conduct a power quality audit.
- Improper bonding, including mechanical integrity issues with the equipment grounding conductor (EGC). Conduct a bonding inspection.
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.