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Subject: 
8475 -- motors and steering Oh My
Newsgroups: 
lugnet.org.ca.rtltoronto
Date: 
Sat, 28 Dec 2002 21:26:09 GMT
Viewed: 
1412 times
  
Were you using a geared 9v motor non loaded? If so, then it's not
surprising that you noticed no difference.


Yes I was testing on an unloaded 9V geared motor. Thats how my
RPM-o-Meter works best.


Try it with a load. I tried it with a weight at the end of an arm, and
at one point on the controller it just buzzed, and at the next it
rotated very slowly, and at the next it rotated faster.

Here is a pic of what I used:
http://members.rogers.com/4tee2/DCP_1063.jpg

Thats a lego weight at the end of that arm.

I just re-did this test and you are correct.  when you load a geared
motor (i put a 40t gear  on the motor and put friction on the teeth)
then you can perceive 3 states  of "something"

Darn it... why did I have to go and loan my multimeter to me dad.  I
want to put a DM meter on this and see what volts  I get.

Trevyn... do this and let me know.  I'm curious if its PWM or just a
lower voltage.



Chris



Message has 2 Replies:
  Re: 8475 -- motors and steering Oh My
 
It is indeed PWM. I got out my oscilliscope and checked it, and here are the results I got: At setting 1 (closest to off): Th: 1ms Tl: 2ms Tt: 3ms 9Vpp At setting 2: Th: 2ms Tl: 1ms Tt: 3ms 9Vpp And at full on, it's just 9v DC. (...) (22 years ago, 29-Dec-02, to lugnet.org.ca.rtltoronto)
  Re: 8475 -- motors and steering Oh My
 
(...) It doesn't matter. DMM's are not good at measuring pulsed signals. (unless you have one of the more expensive true-RMS meters which can calculate the average of a non-sinusoidal waveform. You really need an oscilloscope for this. (...) It will (...) (22 years ago, 30-Dec-02, to lugnet.org.ca.rtltoronto)

Message is in Reply To:
  Re: 8475 -- a good buy
 
(...) Am not!! (...) Were you using a geared 9v motor non loaded? If so, then it's not surprising that you noticed no difference. Try it with a load. I tried it with a weight at the end of an arm, and at one point on the controller it just buzzed, (...) (22 years ago, 28-Dec-02, to lugnet.org.ca.rtltoronto)

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