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 Posted: Sun Jul 27, 2008 7:05 pm Post subject: Cable strand broken |
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Dear group members,
i have encountered one problem and need to analyzed it before taking
any preventive action.
Contorl cable (1/8", 7X19, steel cable) strands wires were found
broken in the area where it run overs pulleys (phenolic). I have came
to know that these area are critical to fatigue but couldnt figured
out the reason and mechanism which led to such damage near pulleys. if
some one can explain me the propbable causes / reason which can led to
such occurrences or reasons which can aggravate the situation, so that
i can based my maintenance procedures and frequency to avoid future
recurrence.
hope for a sound engineering / scientific reply from group members.
thanks |
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jim beam
Guest
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| Posted: Mon Jul 28, 2008 6:28 am Post subject: Re: Cable strand broken |
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kashif_ashkar@hotmail.com wrote:
[quote]Dear group members,
i have encountered one problem and need to analyzed it before taking
any preventive action.
Contorl cable (1/8", 7X19, steel cable) strands wires were found
broken in the area where it run overs pulleys (phenolic). I have came
to know that these area are critical to fatigue but couldnt figured
out the reason and mechanism which led to such damage near pulleys. if
some one can explain me the propbable causes / reason which can led to
such occurrences or reasons which can aggravate the situation, so that
i can based my maintenance procedures and frequency to avoid future
recurrence.
hope for a sound engineering / scientific reply from group members.
thanks
[/quote]
simple bending fatigue. try a larger radius on the pulley. if that>s
not possible, better material/surface finish quality on the cable
[strands] might help. |
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deu
Guest
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| Posted: Wed Jul 30, 2008 12:06 am Post subject: Re: Cable strand broken |
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"jim beam" <spamvortex@bad.example.net> wrote in message
news:ksCdnaVNGJAjvRDVnZ2dnUVZ_vjinZ2d@speakeasy.net...
[quote]kashif_ashkar@hotmail.com wrote:
Dear group members,
i have encountered one problem and need to analyzed it before taking
any preventive action.
Contorl cable (1/8", 7X19, steel cable) strands wires were found
broken in the area where it run overs pulleys (phenolic). I have came
to know that these area are critical to fatigue but couldnt figured
out the reason and mechanism which led to such damage near pulleys. if
some one can explain me the propbable causes / reason which can led to
such occurrences or reasons which can aggravate the situation, so that
i can based my maintenance procedures and frequency to avoid future
recurrence.
hope for a sound engineering / scientific reply from group members.
thanks
simple bending fatigue. try a larger radius on the pulley. if that>s not
possible, better material/surface finish quality on the cable [strands]
might help.
[/quote]
Possibly groove radius on the pulley as well, either too tight or too slack
can do it. |
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Guest
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| Posted: Thu Jul 31, 2008 4:11 pm Post subject: Re: Cable strand broken |
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On Jul 28, 6:28 am, jim beam <spamvor...@bad.example.net> wrote:
[quote]kashif_ash...@hotmail.com wrote:
Dear group members,
i have encountered one problem and need to analyzed it before taking
any preventive action.
Contorl cable (1/8", 7X19, steel cable) strands wires were found
broken in the area where it run overs pulleys (phenolic). I have came
to know that these area are critical to fatigue but couldnt figured
out the reason and mechanism which led to such damage near pulleys. if
some one can explain me the propbable causes / reason which can led to
such occurrences or reasons which can aggravate the situation, so that
i can based my maintenance procedures and frequency to avoid future
recurrence.
hope for a sound engineering / scientific reply from group members.
thanks
simple bending fatigue. try a larger radius on the pulley. if that>s
not possible, better material/surface finish quality on the cable
[strands] might help.- Hide quoted text -
- Show quoted text -
[/quote]
well i have checked pulleys as well, in some pulleys i have observed
cable groove marks in the pulley. however, i have tested the cable
sample with broken wire strands and their breaking strenght was
passing the ASTM standard with the exception of one sample that failed
to qualify the tests.
Bending loads can cause this problem, but in my case the lap angle on
the pulleys is around 10-20 degree,which i think can not contribute
much in my case.
hope that this new infomartion might help the members in further
assisting me in correct analysis.
regards |
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jim beam
Guest
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| Posted: Fri Aug 01, 2008 7:08 am Post subject: Re: Cable strand broken |
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kashif_ashkar@hotmail.com wrote:
[quote]On Jul 28, 6:28�am, jim beam <spamvor...@bad.example.net> wrote:
kashif_ash...@hotmail.com wrote:
Dear group members,
i have encountered one problem and need to analyzed it before taking
any preventive action.
Contorl cable (1/8", 7X19, steel cable) strands wires were found
broken in the area where it run overs pulleys (phenolic). I have came
to know that these area are critical to fatigue but couldnt figured
out the reason and mechanism which led to such damage near pulleys. if
some one can explain me the propbable causes / reason which can led to
such occurrences or reasons which can aggravate the situation, so that
i can based my maintenance procedures and frequency to avoid future
recurrence.
hope for a sound engineering / scientific reply from group members.
thanks
simple bending fatigue. �try a larger radius on the pulley. �if that>s
not possible, better material/surface finish quality on the cable
[strands] might help.- Hide quoted text -
- Show quoted text -
well i have checked pulleys as well, in some pulleys i have observed
cable groove marks in the pulley. however, i have tested the cable
sample with broken wire strands and their breaking strenght was
passing the ASTM standard with the exception of one sample that failed
to qualify the tests.
[/quote]
breaking strength is not fatigue strength - fatigue is your problem.
[quote]
Bending loads can cause this problem, but in my case the lap angle on
the pulleys is around 10-20 degree,which i think can not contribute
much in my case.
[/quote]
angle is not radius. radius defines bending stress. see point above.
[quote]
hope that this new infomartion might help the members in further
assisting me in correct analysis.
regards[/quote] |
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