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Subject: 
Re: Avoiding motor stalls
Newsgroups: 
lugnet.technic
Date: 
Sat, 9 Jul 2005 13:13:17 GMT
Viewed: 
3492 times
  
In lugnet.technic, Jordan Bradford wrote:
If you can sort that out in your mind, this means the tire is spinning
{quickly}. Very, {very} quickly. It is fast enough that trying to stop it
with your finger is very easy, and that's when the motor stalls. Actually, it
doesn't technically stall; it still turns inside the clutch gear, but it has
to work very hard to do so.

What advice can you give me to avoid breaking any more motors? The clutch
gear works in normal gear trains because the motor doesn't have to work very
hard to begin with: it spins quickly and produces lots of torque farther down
the line. But here I'm doing the opposite. If I had an RC motor I would try
using that, since they are more powerful, but right now I'm stuck with normal
9V motors. Oh, I also have one of those weird motors (no axle, but an axle
hole) from the monkey set, but I don't know how it compares to regular ones.

This may not eliminate stalls, but try adding a bunch of
spinning mass (i.e., a flywheel) somewhere in your gear
train, preferably at the output.  A big Technic tire
(like from 8448 or something similar) would work nicely
for this.  This will at least make it more difficult
to stop the gear train once the flywheel is spinning.

Could you try softer (balloon-type) tires on your ball
launcher, to make it more tolerant of imperfect
spacings?

To do both, try something like Philo's Hammerhead CD
launcher:

  http://www.philohome.com/hammerhead/hammerhead.htm

You're right about clutch gears, they generally work
best when gearing down rotation speeds.  Perhaps you
could gear down some, then gear back up again?

I've found that RC motors, while very powerful, stall
in a nasty way: you have to cut the power to get them
unstuck again (the thermistor needs to cool down).

Just a few random ideas...
-Tim



Message is in Reply To:
  Avoiding motor stalls
 
I broke another 9V motor. See my (URL) post> for the first story. I'm building what amounts to a pitching machine for the Great Ball Contraption. In most TECHNIC building you're building a gear train to produce lots of power at the expense of speed. (...) (19 years ago, 9-Jul-05, to lugnet.technic, lugnet.robotics, FTX)

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