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HB-25 #29144 Mounting — Parallax Forums

HB-25 #29144 Mounting

RobotWorkshopRobotWorkshop Posts: 2,307
edited 2010-08-16 18:14 in Robotics
I'm getting ready to mount a pair of HB-25 motor controllers. Before I mount them there is one question that I can't seem to find the answer in any of the documentation. (Perhaps I just missed it)

- Is the heat sink electrically isolated from the battery/motor leads? If this is the case then mounting will be easy. Otherwise I'll need to isolate each one from the chassis of the robot.

Robert

Comments

  • SeariderSearider Posts: 290
    edited 2010-08-16 10:36
    I don't remember doing anything special when I mounted mine. they are mounted to an aluminum an steel chasis along with the Parallax motor mounts. Of course it would be easy enough to find out. All you have to do is wire it up without power and get out an ohm meter.
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2010-08-16 12:24
    I have seen some motor controllers where the heat sinks are connected to one of the leads so I had to ask to see if anyone else brought this up before. I will do some testing just to be safe.

    If the docs for the HB-25 get another revision this point should be covered so that everyone knows if it is safe to mount multiple HB-25's to the same piece of metal framework.

    If the integrated heat sink is isolated it should be added as a "Feature" on the docs for it like:

    - Electrically isolated heat sink for ease of mounting (or something like this)

    Or, if it is connected to either of the supply leads or motor lines then it should be covered.

    Robert
  • ercoerco Posts: 20,256
    edited 2010-08-16 13:30
    Robert: I'm sure someone in this Forum can answer your question.

    But wouldn't you rather wait and be surprised? :)
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2010-08-16 18:11
    Ok, after checking over the HB-25 by looking at the traces and then with the meter it appears that the heatsink (with holes for mounting) are connected to the negative lead on the power coming into the HB-25. It would be fine to mount both HB-25's on the same metal base since they will share the same ground. However this may be a concern if you don't want the chassis as battery ground or have a positive as the chassis (don't know why but some may).

    If the docs are updated I hope Parallax can add a note that the mounting holes are connected to the ground lead.....

    Robert
  • Ken GraceyKen Gracey Posts: 7,390
    edited 2010-08-16 18:14
    Robert, no problem.

    http://forums.parallaxinc.com/forums/default.aspx?f=21&m=151769

    I'll have the internal Product Owner verify and update the documentation after reading this thread..

    Excellent question.

    Ken Gracey
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