Thread: Difference in forward/reverse drill motor speed
View Single Post
  #15   Spotlight this post!  
Unread 24-06-2002, 00:20
archiver archiver is offline
Forum Archival System
#0047 (ChiefDelphi)
  
Join Date: May 2001
Location: Pontiac, MI
Posts: 21,214
archiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond repute
Re: I am wrong.
Posted by Alan Ing at 2/9/2001 9:31 PM EST


Engineer on team #368, Kika Mana, from McKinley High School.


In Reply to: I am wrong.
Posted by Joe Johnson on 2/8/2001 2:39 PM EST:



: I just got a frantic message from my Johnson Electric contact. It seems that he was wrong yesterday when he told me the motor was not biased.

: When he confirmed with his manufacturing sources in Hong Kong, they told him that the magnets are oreinted 15 degrees with respect to the brushes, making the motor performance asymmetrical.

: So... I was wrong. Sorry for misleading folks.

: But... I am still of the opinion that this is not such a big deal. Again, I believe driver skill can compensate very effectively.

:
: Yet... I have to confess that because the design on Chief Delphi 6 is such that we can change the motor orientation without changing any parts, we will probably have them installed to run in the same direction.

: Bottom line:

: If it is easy, I say do it. If it is hard, I say don't bother.

: Joe J.

:
: P.S. I KNEW that I should never take sides against The Heros of Tomorrow (and especially Mike Gray & Jim Meyer) and/or Raul-the-Magnificent -- ah well, live and learn.

: P.P.S. I am going to try to get Johnson to give me the CCW and CW motor curves. I am very curious to see the differences on paper.

Joe, thanks for the last minute motor seminar at the kickoff, it was really informative.

In regards to that drill motor. My guess is that the motor curves are going to be significantly different. Our robot uses one motor in the forward direction and one in reverse. We are pretty sure that friction is not an issue. Our robot definitely turns right faster than left. We put a meter on the motor and made some continuous turns in both directions. When turning one way, the motors are drawing 10 amps (both motors running forward), but in the other direction (both motors running backwards), it is drawing about 18 amps. This is the case for either motor. Seems pretty significant. Some robots might pop their relays while turning in one direction and controlling the stretcher but not in the other direction. Anyway, I would recommend measuring the current through both motors while turning to make sure your gearing is appropriate for both directions.



__________________
This message was archived from an earlier forum system. Some information may have been left out. Start new discussion in the current forums, and refer back to these threads when necessary.