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Maintenance of motors in hazardous and non hazardous areas

Maintenance of motors in hazardous and non hazardous areas

Maintenance of motors in hazardous and non hazardous areas

(OP)
We maintain our motors,whether in a hazardous area or not, 3 yearly and 6 yearly. 3 yearly is a visual, as required under BS EN 60079-Electrical Apparatus for Explosive Gas Atmospheres, and 6 yearly is an intrusive/overhaul based on when we can have it from production. The problem we have are the bearings(failing and damaging flamepath of the motor which if a haz atmosphere is present....Boom!), which guidance from ABB says will require replacement at 20000 hours(Every 2.6 years) but of course this dependant upon number of stop starts,orientation etc.Some motors like HVAC motors run 24/7 so could have run 52500 hours before an overhaul though they are predominantly in safe areas so could be run to destruction? Other motors in the production areas which are Zone 2 Cat 11B T3 run at various times and in a 6 year period could have only run 10000 hours so do not need major overhaul and bearing replacement. We could condition monitor but we are looking to program a SAP Preventative maintenance program which spits out the maintenances at the set periods above.  I would appreciate your views on motor maintenance please as we need,like all industry,to make our maintenance practical yet effective whilst covering the regulations.  

RE: Maintenance of motors in hazardous and non hazardous areas

Bearing life depends on factors like speed, lubrication integrity (proper grease and proper amount of grease), operating temperature, vibration etc.

Best to invest money for on-line condition monitoring of bearing temp and vibration and have a well-defined, equipment-specific early warning system. Blindly replacing bearing based on running hours is not very scientific, imo. For one, you could be replacing perfectly good bearings (cost and time) and two, you could screw up the disassembly/reassembly process leading to an early disaster.

Muthu
www.edison.co.in

RE: Maintenance of motors in hazardous and non hazardous areas

I have been told that rolling element bearings (ball, roller etc) have a statistical life.  I seem to remember that "B1" was the factor used in small motors, and this gave an average life of 30,000 hours. Why not post in the Bearings forum and see if you can get better advice?

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