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Ecmweb 8218 Electrical Troubleshooting Quiz Item
Ecmweb 8218 Electrical Troubleshooting Quiz Item
Ecmweb 8218 Electrical Troubleshooting Quiz Item
Ecmweb 8218 Electrical Troubleshooting Quiz Item
Ecmweb 8218 Electrical Troubleshooting Quiz Item

Electrical Troubleshooting Quiz - May 24, 2016

May 24, 2016
How to solve a plant's motor overload problem.

You work in a large plant that’s divided into production areas with specific purposes. For example, there’s a stamping area and a finishing area, plus there are areas for specific product lines.

One of the product line areas is running into order completion failures because of frequent downtime. The responding electricians nearly always find blown motor overloads. The maintenance manager, being from Detroit, nicknamed the area “Motor Overload City.” The production superintendent has ordered that the motor control enclosures be propped open with a floor fan blowing into them until this issue is resolved.

How do you solve this problem?

Close those enclosures, and remove the fan; that dangerous situation violates OSHA regulations. The overloads are blowing because the motors are overloaded, so determine the cause of the overload.

If just one motor had this problem, you’d suspect load issues. With so many motors, maybe you have a common load-based problem, such as poor lubrication practices with the gearboxes.

But a more likely cause is the supply power. Perhaps there is excessive voltage drop on the feeder to that area, and the lower voltage means a higher current draw through those overloads. Or power factor is low, thus more current is required for the same work. Conduct a thorough power analysis as your first step in solving this.

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