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Sabertooth 2x32 input and output voltage

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by gigi, Apr 13, 2019.

  1. gigi

    gigi Active Member

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    My Motion Simulator:
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    Hallo,
    for my new project I use 4 motors 24v 350w each, 2 sabertooth 2x32 and 2 psu 24v 1000w. the psu output voltage is set to 24,2 v so at each card arrive 24,2 v. My problem is that in test output voltage from card to motors is only 6,5/6,8v max. It’ normal.? the values are recordered directly to the board .Therefore voltage drops due to cable are excluded. I read in sabertooth manual that output voltage should be 95% of input voltage. in my case 6,5v of output to motor is approx 25% of 24,2 V input from psu to card
    thanks for support
    Last edited: Apr 13, 2019
  2. BlazinH

    BlazinH Well-Known Member

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    How do you know that the 2x32s output is set at full speed and what card? And check it with Describe to make sure no limiting values are present.
    Last edited: Apr 14, 2019
  3. gigi

    gigi Active Member

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    2DOF, JRK, 4DOF
    Hi BlazinH thanks for your support
    Can you please explain how set output at full speed, and where in describe software set no limiting value? In Arduino sketch power is set to 255 but in sabertooth I don’t know how set no limiting values. I only set max current value at 40ah
    thanks
    Last edited: Apr 14, 2019
  4. gigi

    gigi Active Member

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    2DOF, JRK, 4DOF


    This is a video that show motor output voltage during aa test.
  5. gigi

    gigi Active Member

    Joined:
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    My Motion Simulator:
    2DOF, JRK, 4DOF
    Today I changed the new 6mm big cables. Unfortunately the problem has not been solved. But I did another test that made me realize that probably the problem is power supplies that do not supply enough current to power 2 motors.
    Each card (sabertooth 2x32) is powered by a 24v 1000w 40ah power supply, precisely this:
    https://simukit.com/alimentations/11-alimentation-24v-1000w.html
    With the trim I set a 24.6V output current
    The engines are TRANSTECNO ECM 250.240 24V 350W I also enclose the engine technical sheet.
    I noticed that with only one motor connected to the card everything works fine, while if I connect 2 motors there seems to be not enough current. The motors under load (around 150kg) behave like the starter of the car when we try to start with the flat battery. It is evident that the power supply fails to supply sufficient current for both motors. The thing is quite strange also because Simukit uses for its kit 3dof 2 power supplies like these for 3 motors from 24v 400W and I believe that to a power supply they connect 2 motors of 24v 400w. Of course I will also ask them
    I could perhaps buy 2 more power supplies and power each card with two power supplies in parallel .... I know it's not a recommended operation but I wouldn't know how to do otherwise
    Meanwhile, if anyone has any suggestions to solve my problem, I thank them.

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