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Subject: 
Re: moving in a straight line with two motors?
Newsgroups: 
lugnet.robotics
Date: 
Fri, 13 Nov 1998 18:27:28 GMT
Original-From: 
Eric Brandwine <ericb@!nomorespam!mitre.org>
Viewed: 
2019 times
  
"eh" == Eric Hodges <eric.hodges@platinum.com> writes:

eh> -----Original Message-----
In order to regain the power of having 2 drive motors, you can run 2
motors off one output port, and couple the shafts together.  Of
course, that brings the total motor count to 3, rather than 2, but it
still only occupies 2 of the motor outputs.

eh> I don't think it works that way.  Will hooking 2 motors to the same power
eh> source provide twice as much power?  I think the limiting factor is the
eh> current from the power source, not the number of motors.  But I could be
eh> wrong.

Not that I have any facts to back me up.....

I looked at kekoa's pictures of the disassembled RCX....  The motor
driver chips are ELEX 10402B / 9980A / 4597.  About which I was able
to find absolutely nothing.  Oh well.

Most of the motor drivers that I have run across supply on the order
of 1 amp, to within a factor of 2 or so.  1300 mAH is generous for AA
batteries, and 7-800 is more like it.  I am still on my first set of
batteries in my RCX, so I have 0 datapoints.  (Once again, that lack
of facts....)  However, I have had the thing running for at least a
couple of hours, most of it with 2 motors churning.  That puts average
motor current draw at less than 1/4 amp per motor.

So I conclude, based on conjecture and hand waving, that it would work
as I stated.  You do bring up a good point though.  If anyone tracks
down a data sheet for that chip, lemme know.

ericb




--
Eric Brandwine, Systems Engineer | What is the definition of an engineer?
EricB@Mitre.org                  |   Someone who solves a problem you
MITRE Corporation, McLean VA     |   didn't know you had in a way you
(703) 883-3319 F: (703) 883-1917 |   don't understand.



Message has 1 Reply:
  Re: moving in a straight line with two motors?
 
(...) There needs to be a link to this somewhere: Peter Phillips pointed out a long while back (my messages from him are dated Sep 21) that the specs to the chip are here: (...) drivers. I don't know if he told the rest of the list about this, if (...) (26 years ago, 13-Nov-98, to lugnet.robotics)

Message is in Reply To:
  RE: moving in a straight line with two motors?
 
-----Original Message----- From: Eric Brandwine [SMTP:ericb@mitre.org] Sent: Friday, November 13, 1998 8:39 AM To: John Scott Kjellman Cc: lego-robotics@crynwr.com Subject: Re: moving in a straight line with two motors? <snip> (...) I don't think it (...) (26 years ago, 13-Nov-98, to lugnet.robotics)

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