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In lugnet.trains, James Brown writes:
> In lugnet.trains, Ross Crawford writes:
> > In lugnet.trains, Thomas Avery writes:
>
> > > The difficult part of stalling a geared motor is containing the large forces
> > > generated on the structure surrounding the gear train. It's very difficult
> > > to stall one without a super-strong construction. Your more likely to break
> > > apart your model, or your gears, first.
> >
> > Yep, and with this one using an 8-tooth gear straight on the rack, even with
> > a solid structure you'd be very likely to break the gear. If you can supply
> > an accurately timed "pulse", that would reduce the risk, but with the geared
> > motors, it takes very little time to pull your structure apart. A safer way
> > would be provide some give through a clutch mechanism or even a clutch gear
> > http://www.peeron.com/inv/parts/60c01, but that would probably increase the
> > size of your switch.
>
> Hmm, Ok. Since it sounds like I'm not risking the motor, and I have lots of
> 8 tooth gears, I'm going to experiment by leaving the motor on for a while,
> and seeing what happens.
Well, some good, some bad. The good is that leaving the motor going in one
direction for 20 minutes causes no separations and no apparent stress to any
parts. The bad is that it did overheat the motor, which wouldn't run again
until it cooled down. Presumably doing that too much would eventually kill
the motor. Motor's being $20 parts, I'm willing to let someone else test
that theorum. :o
I also ended up doing much more intensive stress testing, and discovered
that the assembly needs more plates and less bricks. :p
Of the 5 I had assembled, 3 worked like a charm: literally hundreds of
switches without even hinting at coming apart, no matter which of my 4
switches they were on - and one of my switches is really stiff. The other
two would have the 4x6 plate on the bottom separate (relatively) quickly -
about 20 switches and 40-50 switches respectively.
The fix was fairly straightforward, though more part-intensive: change the
bricks for plates. The extra gripping power that 3 stacked plates has over
1 brick made the difference. Now all 5 switches work like magic for
hundreds of repetitions.
It sure looks cool switching 4 turnouts at once with the touch of a button. :)
Thanks again very much for the insights, guys - you seriously cut down my
troubleshooting time on this assembly.
I'll update the instructions and call the project finished. :)
thanks,
James
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Message has 2 Replies:
 | | Re: Motorized Switch
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| <SNIP> troubleshooting time on this assembly. (...) Will you be posting a new .mpd file to your brickshelf account showing the changes? BTW the othe .mpd file was *not* right. What I mean by that is that usually when one creates a .mpd file the (...) (22 years ago, 7-Jun-02, to lugnet.trains, lugnet.technic)
| | | Re: Motorized Switch
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| (...) 20 minutes?!?! Yikes! I've stalled my motors often, but only for a few seconds. I imagined that would be the same situation for your switch. Leaving it on for 20 min- you're boldly going where no Technic-head has gone before... ;-) TJ p.s. I (...) (22 years ago, 7-Jun-02, to lugnet.trains, lugnet.technic)
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Message is in Reply To:
| | Re: Motorized Switch
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| (...) Hmm, Ok. Since it sounds like I'm not risking the motor, and I have lots of 8 tooth gears, I'm going to experiment by leaving the motor on for a while, and seeing what happens. thanks very much for the information, guys! This is exactly the (...) (22 years ago, 7-Jun-02, to lugnet.trains, lugnet.technic)
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