Electrical Troubleshooting Quiz - September 27, 2016
A hot process area inside the plant has a pair of exhaust fans for removing waste heat. Every few days, operators report squealing coming from one of these fans. Knowing the squealing indicates something is wrong, the maintenance supervisor sends whoever is available to the roof to fix the squealing. This way, he figures, he’ll delay the inevitable breakdown and avoid the ventilation problems and costs associated with it.
The plant manager has, several times, discussed with the maintenance supervisor the fact that these breakdowns occur far too often despite the rapid dispatch when the squealing is noted. He wants you to solve the breakdown problem. Where should you start?
The squealing could indicate any of several problems. Techs that are told to “fix the squealing,” will probably do that instead of solving the underlying cause. The fact that breakdowns happen indicates this is what they’re doing here. Techs at one appliance factory stopped the squealing by applying randomly selected grease to the fan belt!
Rather than waste time figuring out what mistakes were made previously, go through the whole system for each fan. Start by using a vibration tester on the motor with no load connected; fix any problems. Clean the load pulley, and install a new belt under proper tension. Review the maintenance procedure and fix it as necessary.
