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Subject: 
Re: What is RPM of Gear Motor???
Newsgroups: 
lugnet.robotics
Date: 
Wed, 7 Jul 1999 05:52:51 GMT
Viewed: 
825 times
  
Using a Futaba 9ZAP radio with a built in optical tachometer and the two bladed
LEGO prop I got 380 rpm for the gearhead motor and 4320 rpm for the older
nongeared motor. Of course this was done with a battery box and brand new
batteries so I am sure that these results will vary with each motor. I also did
all the possible gear ratios you can make with LEGO gears and found out that
none of the combinations will allow you to drop the old 9v nongeared motor down
to the same rpm as the gearhead motor.

Peter

In lugnet.robotics, Luis Villa writes:
On Tue, 6 Jul 1999, Dave Baum wrote:

Keep checking the math.  I clocked the motor at 330 - 350 rpm.  I used the
rotation sensor driven directly by the motor.  From analysis of the RCX
firmware, the rotation sensor should be accurate to 1250 rpm, so I'm
pretty confident of it being in the 350 range.


Dave-
Where are you getting that 1250 rpm upper limit from? While I haven't
counted exactly yet, I'm dropping only 20 counts out of every
thousand at ~15,000 rpm. I had assumed this was mainly gear slop,
since it only appears to occur while driving the rotor in one direction
and then stopping violently, which lets my gearing assembly roll a little
bit even after the driving arm has bee stopped. Let me know about your
analysis-
Luis

#######################################################################

    Profanity is the one language that all programmers understand.
                  -Anonymous

#######################################################################
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics



Message has 1 Reply:
  Re: What is RPM of Gear Motor???
 
(...) You could get close using the differential as an adder. The ratio of speeds above is about 11:1 (its 11.3:1, but lets keep things as integers). That is a prime number, and we know there aren't any lego gear options that give you an 11:1, so (...) (25 years ago, 7-Jul-99, to lugnet.robotics)

Message is in Reply To:
  Re: What is RPM of Gear Motor???
 
(...) Dave- Where are you getting that 1250 rpm upper limit from? While I haven't counted exactly yet, I'm dropping only 20 counts out of every thousand at ~15,000 rpm. I had assumed this was mainly gear slop, since it only appears to occur while (...) (25 years ago, 7-Jul-99, to lugnet.robotics)

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