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Subject: 
Re: drawbridge
Newsgroups: 
lugnet.technic, lugnet.trains
Date: 
Thu, 1 May 2003 11:21:54 GMT
Viewed: 
204 times
  
"James Powell" <wx732@freenet.victoria.bc.ca> wrote in message
news:HE4yp6.15uI@lugnet.com...
Has anyone tried using a single motor, and putting the motor in the
span? I know it isn't prototypical, but if the motor was in the span,
and the string/chain was drawn into the span by a single motor, then the
span would pull itself up evenly. This was just a thought, I haven't
tried it.


I used a single motor, with all cables being passed above the top of the • span
to get to the far side (4 cables).  One trick that I would do if I was • building
another one is to make the cable drums easier to adjust to one another, • since
they tend to get out of sinc even with just a single motor driving them. • (rope
would wind unevenly).

Just a thought when reading this thread:
If you have trouble with motors that do not run with the exacly the same RPM
(I have not found any that match yet), and they should lift each end on this
bridge, why not connect them toghether with a Technic axle? Then you have
the force of BOTH motors working toghether on BOTH sides of the span...

Just a thought...

You can make it mor complex and put a rotation sensor and then program the
RCX so it runs both motors in the exact speed...


Regards
Øyvind Steinnes
http://www.brickshelf.com/cgi-bin/gallery.cgi?m=Phoenix



I found that this system worked OK with a 5.5 track segment bridge.  I'd • be
tempted to try counterweighting a larger bridge, to make it a bit easier • on the
motor for lift force.  Mine was not counterweighted, and put a fair strain • on
the motor (a geared motor).  After motor reduction was 24:1 via worm, • which is
very useful for the self locking if nothing else.




James Powell



Message is in Reply To:
  Re: drawbridge
 
(...) I used a single motor, with all cables being passed above the top of the span to get to the far side (4 cables). One trick that I would do if I was building another one is to make the cable drums easier to adjust to one another, since they (...) (21 years ago, 30-Apr-03, to lugnet.technic, lugnet.trains)

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