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Local isolator near drive, good or bad?

We have been asked by operations to look at streamlining isolation tasks for mechanical and process jobs. 

I have suggested having local isolators next to the required drives (belt driven fans / pumps etc), which can be operated by anyone, instead of MCC located isolators or even fuse pulling, done by specifically trained people.  

I cannot find anything about best practice or pro/cons on something like this, so I a hoping people here could offer advice?

Parents
  • Other thought is to check that there's no dependency between individual motors - e.g. you usually don't want to isolate a motor that's driving a conveyor belt if whatever putting things onto the conveyor is still running (otherwise you end up with a big heap of products falling onto the floor and very upset management). Similarly for less obvious things where the process is more complicated (e.g. pumps or fans and heaters - where things could overheat if the fan/pump is off and the heater still on). Keeping single means of isolating a group of things together can help avoid some of the worst mistakes in that respect.

       - Andy.

Reply
  • Other thought is to check that there's no dependency between individual motors - e.g. you usually don't want to isolate a motor that's driving a conveyor belt if whatever putting things onto the conveyor is still running (otherwise you end up with a big heap of products falling onto the floor and very upset management). Similarly for less obvious things where the process is more complicated (e.g. pumps or fans and heaters - where things could overheat if the fan/pump is off and the heater still on). Keeping single means of isolating a group of things together can help avoid some of the worst mistakes in that respect.

       - Andy.

Children
  • Or something closer to an E-stop loop with key switches so the whole line can be killed and locked off at any one of a few key points. However there are rules about this - a run of series switches and any old contactor will not quite do for isolation for working on parts that may come live or machinery that may restart in a dangerous way if that fails.

    Mike.