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Re: F7 PROBLEM AGAIN!!!

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  • Glen Chenier
    ... Have sent a private email to recommend things to check. Mechanical is certainly a possibility, but it may be that motor brushes are worn short and the
    Message 1 of 6 , Dec 2, 2004
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      --- In z_scale@yahoogroups.com, "Jerry Salamon" <jjssmm01@t...> wrote:

      >> One of my F7's will only run backwords but not forwards!

      Have sent a private email to recommend things to check. Mechanical
      is certainly a possibility, but it may be that motor brushes are worn
      short and the slight angled end from forward running only is now too
      short for good commutator contact. In reverse (assuming the brush
      makes enough contact to let the motor turn enough to get started) the
      wobble in the brush holder could still let the angled longer brush
      edge make contact with the commutator in reverse only.

      I've had to replace brushes after about 500 hours of SLOW operation
      of one of my own locos (it just quit one day but the headlight was
      lit, and never tried running in reverse, just checked and replaced
      the brushes), and only know this time because as a test loco i logged
      the running time for the most part. Faster operation and hauling a
      consist would wear brushes sooner.

      Other than my own loco and 1 other repair i've never seen a running
      problem caused by worn brushes. My practice is to replace them when
      the wear exceeds 0.5mm, they still work at wear of 1mm, and so far no
      unit has come in with severe brush problems other than minor wear up
      to 1mm.

      If anyone has experienced problems caused by severely worn brushes
      your input is requested. Has anyone actually seen where worn brushes
      allowed running in the opposite direction to what the loco is used
      to? And can anyone who has replaced brushes provide data as to
      running time (hours), average speeds used, average length of consist
      etc? In spite of all the variables involved it could be useful to
      get some idea of typical brush life under these various operating
      conditions.
    • Jerry Salamon
      ... Mechanical ... worn ... too ... the ... Glen, I have not been able to reply to you because my computer is down. I am using the one at work to reply. As
      Message 2 of 6 , Dec 3, 2004
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        --- In z_scale@yahoogroups.com, "Glen Chenier" <chenierfam@c...>
        wrote:
        >
        > --- In z_scale@yahoogroups.com, "Jerry Salamon" <jjssmm01@t...>
        wrote:
        >
        > >> One of my F7's will only run backwords but not forwards!
        >
        > Have sent a private email to recommend things to check.
        Mechanical
        > is certainly a possibility, but it may be that motor brushes are
        worn
        > short and the slight angled end from forward running only is now
        too
        > short for good commutator contact. In reverse (assuming the brush
        > makes enough contact to let the motor turn enough to get started)
        the
        > wobble in the brush holder could still let the angled longer brush
        > edge make contact with the commutator in reverse only.

        Glen,

        I have not been able to reply to you because
        my computer is down.
        I am using the one at work to reply.
        As soon as I have my computer back up
        I will reply..

        Jerry
        >
        > I've had to replace brushes after about 500 hours of SLOW
        operation
        > of one of my own locos (it just quit one day but the headlight was
        > lit, and never tried running in reverse, just checked and replaced
        > the brushes), and only know this time because as a test loco i
        logged
        > the running time for the most part. Faster operation and hauling
        a
        > consist would wear brushes sooner.
        >
        > Other than my own loco and 1 other repair i've never seen a
        running
        > problem caused by worn brushes. My practice is to replace them
        when
        > the wear exceeds 0.5mm, they still work at wear of 1mm, and so far
        no
        > unit has come in with severe brush problems other than minor wear
        up
        > to 1mm.
        >
        > If anyone has experienced problems caused by severely worn brushes
        > your input is requested. Has anyone actually seen where worn
        brushes
        > allowed running in the opposite direction to what the loco is used
        > to? And can anyone who has replaced brushes provide data as to
        > running time (hours), average speeds used, average length of
        consist
        > etc? In spite of all the variables involved it could be useful to
        > get some idea of typical brush life under these various operating
        > conditions.
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