PWM rate

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  • keithbradley
    Fast Electric Addict!
    • Jul 2010
    • 3663

    #1

    PWM rate

    I came across this formula for determining the best PWM rate to run on escs...thought I would share:

    Motor Kv x Motor Pole Count x Nominal volts used / 20
    www.keithbradleyboats.com
  • m4a1usr
    Fast Electric Addict
    • Nov 2009
    • 2038

    #2
    Is that formula; Motor Kv x Motor poles x pack voltage divided by 20? Didnt work out right for a Castle 1515/1Y.

    2200 x 4 x 14.8 volts divided by 20= 6512 or
    2200 x 4 x 4S divided by 20= 1760?

    Must be my math.

    John
    Change is the one Constant

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    • GP73
      Senior Member
      • Jul 2010
      • 544

      #3
      If I understand correctly, your math is right, the PWM in the first case is 6512Hz or approx 6KHz.
      Last edited by GP73; 05-24-2011, 12:56 AM. Reason: Typo

      Comment

      • m4a1usr
        Fast Electric Addict
        • Nov 2009
        • 2038

        #4
        Originally posted by GP73
        If I understand correctly, you math is right, the PWM in the first case is 6512Hz or approx 6Khz.
        But it doesnt work out for some ESC. A Castle Hydra 240 ESC needs 12khz PWM for the CC/Neu 1515. And a Schulze 40.160 ESC likes the 9 to 19khz setting for a 4 pole motor. Neu motors recommends 11 to 13 khz on their motors. Something isnt right. Either its my math or its the formula. Not sure which. But I would welcome something to use a rule of thumb. Otherwise I'm going to stick with the manufacturers recomendations.

        John
        Change is the one Constant

        Comment

        • Gary
          Fast Electric Addict!
          • Jan 2009
          • 1105

          #5
          Did not know you could change that on castle. How do you do that? Have seen it on other ESC's though.
          PT-45, 109mph, finally gave up after last bad crash
          H&M 1/8 Miss Bud 73 mph
          Chris Craft 16 mph

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          • m4a1usr
            Fast Electric Addict
            • Nov 2009
            • 2038

            #6
            Originally posted by Gary
            Did not know you could change that on castle. How do you do that? Have seen it on other ESC's though.
            Its changeable on the A/C ESC's. Not the Hydra series. Heli's have a recommended setting of 8khz. http://www.castlecreations.com/suppo...0mx-530kv.html

            John
            Change is the one Constant

            Comment

            • keithbradley
              Fast Electric Addict!
              • Jul 2010
              • 3663

              #7
              Originally posted by m4a1usr
              But it doesnt work out for some ESC. A Castle Hydra 240 ESC needs 12khz PWM for the CC/Neu 1515. And a Schulze 40.160 ESC likes the 9 to 19khz setting for a 4 pole motor. Neu motors recommends 11 to 13 khz on their motors. Something isnt right. Either its my math or its the formula. Not sure which. But I would welcome something to use a rule of thumb. Otherwise I'm going to stick with the manufacturers recomendations.

              John
              I've never ran anything other than 8k on an inrunner (Including my 1515-1y) and they've all ran well. I'm not saying you're wrong, but I dont understand why you would need 12k on a Neu 15 series motor...or why you would run a completely different PWM on one ESC than you would on another.
              Still, I would start with the manufacturer's reccomendation. If that works well, then run it. This formula would come into play more when you have a motor that you don't already have info on. For example, my suppo 2200kv 6 pole motors in my EKOS (2200x6x18.5/20). For those motors a good starting point would be 12k.

              I found this formula on another forum. I was researching "outrunner mode" on my castle ICE ESCs as I suspected it being a possible cause of excess current draw in my EKOS. It was posted by a castle creations rep as a guide for people who had no idea where to set the PWM, and he stated that he hadn't come across a conbo that didn't work well with this formula. I can't confirm that, as I just found this info myself, but I will be trying it out with my current and future setups.
              www.keithbradleyboats.com

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