Subject:
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Re: Avoiding motor stalls
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Newsgroups:
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lugnet.technic
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Date:
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Mon, 18 Jul 2005 05:23:54 GMT
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Viewed:
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3553 times
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Update: there are now two motors driving this thing. They each have an 8 tooth
gear that turn a 40-tooth gear placed between them -- instant torque, but less
output speed. I put another 40-tooth gear on the same axle as that one and
connect that with a chain to the clutch gear. Now if the tire gets stuck, the
clutch gear has enough input torque to keep turning, meaning my two motors
aren’t stalling. The tire isn’t spinning as fast as it used to, but it’s still
good enough to shoot out balls.
I also wondered if my RCX batteries’ getting weaker might have affected things,
since lower voltage == lower motor speed, so I’m now powering the two motors
from a train speed regulator turned on all the way. Now the input voltage is
constant.
The suggestion to use a rotation sensor is good, except that I need my RCX for
the mine shaft rescue competition at Brickfest. So, the ball launcher has to
remain mechanical only. The flywheel idea didn’t work because I barely have to
touch the tire to stop it, and a lot of spinning mass wouldn’t change this. For
the same reason, a slipping system using pulleys wouldn’t work: there’s not
enough torque for it to slip.
Now I get to rebuild my contraption, because its structure is too fragile --
it’s a prototype.
Oh, doesn’t the RCX have a current-limiting device in its outputs? I don’t think
the train regulator does. If that is the case, I could use my other RCX, which
is happily version 1.0 and has an AC adapter jack. I was going to use this for
another part of my GBC contribution, but it was just as a glorified power
supply.
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Message is in Reply To:
 | | Avoiding motor stalls
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| 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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