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Amp loss through motor controller?

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  • Victor
    I m tring to drive a windshield wiper motor through a L298 Motor Driver (http://www.hobbyengineering.com/H1918.html) with a computer power supply (12 volt
    Message 1 of 11 , Feb 26, 2007
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      I'm tring to drive a windshield wiper motor through a L298 Motor Driver
      (http://www.hobbyengineering.com/H1918.html) with a computer power
      supply (12 volt line) 6 amps

      If I hook up the power supply directly to the motor it gives me plenty
      of torque but through the motor driver it's weak to weak to drive what
      I need to drive.

      I'm certainly willing to get a stronger motor controller if anyone has
      a better option or upgrade the one I have.

      Thanks in advance
    • Branden Gunn
      Have you measured the current going to the motor directly and through the driver? Is the driver rated for the current spike needed to start the motor up? ...
      Message 2 of 11 , Feb 26, 2007
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        Have you measured the current going to the motor directly and through
        the driver? Is the driver rated for the current spike needed to start
        the motor up?

        On 2/26/07, Victor <sluggo55555@...> wrote:
        > I'm tring to drive a windshield wiper motor through a L298 Motor Driver
        > (http://www.hobbyengineering.com/H1918.html) with a computer power
        > supply (12 volt line) 6 amps
        >
        > If I hook up the power supply directly to the motor it gives me plenty
        > of torque but through the motor driver it's weak to weak to drive what
        > I need to drive.
        >
        > I'm certainly willing to get a stronger motor controller if anyone has
        > a better option or upgrade the one I have.
        >
        > Thanks in advance
        >
        >
        >
        > Visit the SRS Website at http://www.seattlerobotics.org
        > Yahoo! Groups Links
        >
        >
        >
        >


        --
        Branden Gunn
        engunneer@...
        branden@...
      • Stephen Noel
        Branden s right. According to the L298 datasheet, the part is only rated for 2.5A continuous current (per channel). Stall/startup current for a wiper motor can
        Message 3 of 11 , Feb 26, 2007
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          Branden's right. According to the L298 datasheet, the part is only rated
          for 2.5A continuous current (per channel). Stall/startup current for a
          wiper motor can easily be in the 10 to 15A range. It sounds like the
          L298 just doesn't have the guts.

          Branden Gunn said the following on 2/26/2007 2:34 PM:
          >
          >
          > Have you measured the current going to the motor directly and through
          > the driver? Is the driver rated for the current spike needed to start
          > the motor up?
          >
          > On 2/26/07, Victor <sluggo55555@...
          > <mailto:sluggo55555%40yahoo.com>> wrote:
          > > I'm tring to drive a windshield wiper motor through a L298 Motor Driver
          > > (http://www.hobbyengineering.com/H1918.html
          > <http://www.hobbyengineering.com/H1918.html>) with a computer power
          > > supply (12 volt line) 6 amps
          > >
          > > If I hook up the power supply directly to the motor it gives me plenty
          > > of torque but through the motor driver it's weak to weak to drive what
          > > I need to drive.
          > >
          > > I'm certainly willing to get a stronger motor controller if anyone has
          > > a better option or upgrade the one I have.
          > >
          > > Thanks in advance
          > >
          > >
          > >
          > > Visit the SRS Website at http://www.seattlerobotics.org
          > <http://www.seattlerobotics.org>
          > > Yahoo! Groups Links
          > >
          > >
          > >
          > >
          >
          > --
          > Branden Gunn
          > engunneer@... <mailto:engunneer%40gmail.com>
          > branden@... <mailto:branden%40issaquahrobotics.org>
          >
          >

          --
          Stephen Noel
          Pronetiq Consultation
          networks - systems - infrastructure
          http://www.pronetiq.com
          (514) 926-4700
        • Victor
          I m not certain what the start up current is for this motor but it is rated at .91 amps on the low speed I m sure that is continuous and I have no idea what
          Message 4 of 11 , Feb 27, 2007
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            I'm not certain what the start up current is for this motor but it is
            rated at .91 amps on the low speed I'm sure that is continuous and I
            have no idea what the start up current is. do you suppose I could
            double the output by ruining both sides at once or can someone point
            me to a controller that's stronger?


            > Branden's right. According to the L298 datasheet, the part is only
            rated
            > for 2.5A continuous current (per channel). Stall/startup current
            for a
            > wiper motor can easily be in the 10 to 15A range. It sounds like
            the
            > L298 just doesn't have the guts.
            >
            > Branden Gunn said the following on 2/26/2007 2:34 PM:
            > >
            > >
            > > Have you measured the current going to the motor directly and
            through
            > > the driver? Is the driver rated for the current spike needed to
            start
            > > the motor up?
            > >
            > > On 2/26/07, Victor <sluggo55555@...
            > > <mailto:sluggo55555%40yahoo.com>> wrote:
            > > > I'm tring to drive a windshield wiper motor through a L298
            Motor Driver
            > > > (http://www.hobbyengineering.com/H1918.html
            > > <http://www.hobbyengineering.com/H1918.html>) with a computer
            power
            > > > supply (12 volt line) 6 amps
            > > >
            > > > If I hook up the power supply directly to the motor it gives
            me plenty
            > > > of torque but through the motor driver it's weak to weak to
            drive what
            > > > I need to drive.
            > > >
            > > > I'm certainly willing to get a stronger motor controller if
            anyone has
            > > > a better option or upgrade the one I have.
            > > >
            > > > Thanks in advance
            > > >
            > > >
            > > >
            > > > Visit the SRS Website at http://www.seattlerobotics.org
            > > <http://www.seattlerobotics.org>
            > > > Yahoo! Groups Links
            > > >
            > > >
            > > >
            > > >
            > >
            > > --
            > > Branden Gunn
            > > engunneer@... <mailto:engunneer%40gmail.com>
            > > branden@... <mailto:branden%40issaquahrobotics.org>
            > >
            > >
            >
            > --
            > Stephen Noel
            > Pronetiq Consultation
            > networks - systems - infrastructure
            > http://www.pronetiq.com
            > (514) 926-4700
            >
          • Stephen Noel
            The 0.91 Amps is likely the no-load speed. As soon as you apply a load and start extracting torque from the motor, the current will shoot up tremendously. I
            Message 5 of 11 , Feb 27, 2007
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              The 0.91 Amps is likely the no-load speed. As soon as you apply a load
              and start extracting torque from the motor, the current will shoot up
              tremendously.

              I think you should follow Branden's advice and put a ammeter in series
              with the motor, then drive it using your wide-open power supply (no
              controller) and measure the current under the expected torque load. This
              will tell you how powerful your controller must be.

              Many controllers will allow you to gang their output channels together
              to provide more drive capacity. I don't know about the Hobby Engineering
              unit that you are using. Perhaps someone else could contribute here?

              Victor said the following on 2/27/2007 3:06 AM:
              >
              >
              > I'm not certain what the start up current is for this motor but it is
              > rated at .91 amps on the low speed I'm sure that is continuous and I
              > have no idea what the start up current is. do you suppose I could
              > double the output by ruining both sides at once or can someone point
              > me to a controller that's stronger?
              >
              > > Branden's right. According to the L298 datasheet, the part is only
              > rated
              > > for 2.5A continuous current (per channel). Stall/startup current
              > for a
              > > wiper motor can easily be in the 10 to 15A range. It sounds like
              > the
              > > L298 just doesn't have the guts.
              > >
              > > Branden Gunn said the following on 2/26/2007 2:34 PM:
              > > >
              > > >
              > > > Have you measured the current going to the motor directly and
              > through
              > > > the driver? Is the driver rated for the current spike needed to
              > start
              > > > the motor up?
              > > >
              > > > On 2/26/07, Victor <sluggo55555@...
              > > > <mailto:sluggo55555%40yahoo.com>> wrote:
              > > > > I'm tring to drive a windshield wiper motor through a L298
              > Motor Driver
              > > > > (http://www.hobbyengineering.com/H1918.html
              > <http://www.hobbyengineering.com/H1918.html>
              > > > <http://www.hobbyengineering.com/H1918.html
              > <http://www.hobbyengineering.com/H1918.html>>) with a computer
              > power
              > > > > supply (12 volt line) 6 amps
              > > > >
              > > > > If I hook up the power supply directly to the motor it gives
              > me plenty
              > > > > of torque but through the motor driver it's weak to weak to
              > drive what
              > > > > I need to drive.
              > > > >
              > > > > I'm certainly willing to get a stronger motor controller if
              > anyone has
              > > > > a better option or upgrade the one I have.
              > > > >
              > > > > Thanks in advance
              > > > >
              > > > >
              > > > >
              > > > > Visit the SRS Website at http://www.seattlerobotics.org
              > <http://www.seattlerobotics.org>
              > > > <http://www.seattlerobotics.org <http://www.seattlerobotics.org>>
              > > > > Yahoo! Groups Links
              > > > >
              > > > >
              > > > >
              > > > >
              > > >
              > > > --
              > > > Branden Gunn
              > > > engunneer@... <mailto:engunneer%40gmail.com>
              > > > branden@... <mailto:branden%40issaquahrobotics.org>
              > > >
              > > >
              > >
              > > --
              > > Stephen Noel
              > > Pronetiq Consultation
              > > networks - systems - infrastructure
              > > http://www.pronetiq.com <http://www.pronetiq.com>
              > > (514) 926-4700
              > >
              >
              >

              --
              Stephen Noel
              Pronetiq Consultation
              networks - systems - infrastructure
              http://www.pronetiq.com
              (514) 926-4700
            • Tom Capon
              If you do a search on this list you should find a plenty of pre-packaged motor controllers, ranging from 5-100A. One quick search brought up the Polulu
              Message 6 of 11 , Feb 27, 2007
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                If you do a search on this list you should find a plenty of pre-packaged
                motor controllers, ranging from 5-100A. One quick search brought up the
                Polulu controllers, in the 5-10A range (don't let the 30A number fool you,
                that's an absolute max):

                http://www.pololu.com/products/pololu/0705/

                The L298 is basically a tiny chip, even if you ganged the two channels
                together it will still dissipate a lot of heat. If you want to get anywhere
                close to its rated maximum you need a lot of heatsinking.

                --Tom C.


                On 2/27/07, Stephen Noel < snoel@...> wrote:
                >
                > The 0.91 Amps is likely the no-load speed. As soon as you apply a load
                > and start extracting torque from the motor, the current will shoot up
                > tremendously.
                >
                > I think you should follow Branden's advice and put a ammeter in series
                > with the motor, then drive it using your wide-open power supply (no
                > controller) and measure the current under the expected torque load. This
                > will tell you how powerful your controller must be.
                >
                > Many controllers will allow you to gang their output channels together
                > to provide more drive capacity. I don't know about the Hobby Engineering
                > unit that you are using. Perhaps someone else could contribute here?
                >
                > Victor said the following on 2/27/2007 3:06 AM:
                >
                > >
                > >
                > > I'm not certain what the start up current is for this motor but it is
                > > rated at .91 amps on the low speed I'm sure that is continuous and I
                > > have no idea what the start up current is. do you suppose I could
                > > double the output by ruining both sides at once or can someone point
                > > me to a controller that's stronger?
                > >
                > > > Branden's right. According to the L298 datasheet, the part is only
                > > rated
                > > > for 2.5A continuous current (per channel). Stall/startup current
                > > for a
                > > > wiper motor can easily be in the 10 to 15A range. It sounds like
                > > the
                > > > L298 just doesn't have the guts.
                > > >
                > > > Branden Gunn said the following on 2/26/2007 2:34 PM:
                > > > >
                > > > >
                > > > > Have you measured the current going to the motor directly and
                > > through
                > > > > the driver? Is the driver rated for the current spike needed to
                > > start
                > > > > the motor up?
                > > > >
                > > > > On 2/26/07, Victor <sluggo55555@...
                > > > > <mailto:sluggo55555%40yahoo.com>> wrote:
                > > > > > I'm tring to drive a windshield wiper motor through a L298
                > > Motor Driver
                > > > > > (http://www.hobbyengineering.com/H1918.html
                > > <http://www.hobbyengineering.com/H1918.html>
                > > > > <http://www.hobbyengineering.com/H1918.html
                > > <http://www.hobbyengineering.com/H1918.html>>) with a computer
                > > power
                > > > > > supply (12 volt line) 6 amps
                > > > > >
                > > > > > If I hook up the power supply directly to the motor it gives
                > > me plenty
                > > > > > of torque but through the motor driver it's weak to weak to
                > > drive what
                > > > > > I need to drive.
                > > > > >
                > > > > > I'm certainly willing to get a stronger motor controller if
                > > anyone has
                > > > > > a better option or upgrade the one I have.
                > > > > >
                > > > > > Thanks in advance
                > > > > >
                > > > > >
                > > > > >
                > > > > > Visit the SRS Website at http://www.seattlerobotics.org
                > > <http://www.seattlerobotics.org>
                > > > > <http://www.seattlerobotics.org < http://www.seattlerobotics.org>>
                > > > > > Yahoo! Groups Links
                > > > > >
                > > > > >
                > > > > >
                > > > > >
                > > > >
                > > > > --
                > > > > Branden Gunn
                > > > > engunneer@... <mailto:engunneer% <engunneer%25> 40gmail.com>
                > > > > branden@... <mailto:branden% <branden%25>40issaquahroboti cs.org>
                > > > >
                > > > >
                > > >
                > > > --
                > > > Stephen Noel
                > > > Pronetiq Consultation
                > > > networks - systems - infrastructure
                > > > http://www.pronetiq.com < http://www.pronetiq.com>
                > > > (514) 926-4700
                > > >
                > >
                > >
                >
                > --
                > Stephen Noel
                > Pronetiq Consultation
                > networks - systems - infrastructure
                > http://www.pronetiq.com
                > (514) 926-4700
                >
                >
                >


                [Non-text portions of this message have been removed]
              • Rohit jain
                Hi All, Can somebody advice me in writing an Algorithm for Neural network based Feedback control for Robotic movement . I am using neural network to implement
                Message 7 of 11 , Feb 27, 2007
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                  Hi All,

                  Can somebody advice me in writing an Algorithm for "Neural network based Feedback control for Robotic movement".

                  I am using neural network to implement this but have little idea. I have to design it offline first and then write a program based on the Algorithm.

                  Thank in advance :)

                  ~Rony


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                • Joey Tomlinson
                  ... load ... up ... series ... This ... together ... Engineering ... The two channels of the L298 can be paralleled according to the datasheet
                  Message 8 of 11 , Feb 27, 2007
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                    --- In SeattleRobotics@yahoogroups.com, Stephen Noel <snoel@...>
                    wrote:
                    >
                    > The 0.91 Amps is likely the no-load speed. As soon as you apply a
                    load
                    > and start extracting torque from the motor, the current will shoot
                    up
                    > tremendously.
                    >
                    > I think you should follow Branden's advice and put a ammeter in
                    series
                    > with the motor, then drive it using your wide-open power supply (no
                    > controller) and measure the current under the expected torque load.
                    This
                    > will tell you how powerful your controller must be.
                    >
                    > Many controllers will allow you to gang their output channels
                    together
                    > to provide more drive capacity. I don't know about the Hobby
                    Engineering
                    > unit that you are using. Perhaps someone else could contribute here?

                    The two channels of the L298 can be "paralleled" according to the
                    datasheet (http://www.st.com/stonline/books/pdf/docs/1773.pdf - see
                    fig 7). The paralleled configuration gives a max current of 3A. I'm
                    not sure if this will be enough for your motor though. You should
                    measure the current your motor draws under the required load as
                    Stephen and Branden suggested.
                  • np np
                    You could use the driver IC to drive a MOSFET which will give you loads of amps. www.ckp[-railways.talktalk.net/pcbcad21.htm Joey Tomlinson
                    Message 9 of 11 , Feb 27, 2007
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                      You could use the driver IC to drive a MOSFET which will give you loads of amps.

                      www.ckp[-railways.talktalk.net/pcbcad21.htm


                      Joey Tomlinson <jtomlinson531@...> wrote: --- In SeattleRobotics@yahoogroups.com, Stephen Noel <snoel@...>
                      wrote:
                      >
                      > The 0.91 Amps is likely the no-load speed. As soon as you apply a
                      load
                      > and start extracting torque from the motor, the current will shoot
                      up
                      > tremendously.
                      >
                      > I think you should follow Branden's advice and put a ammeter in
                      series
                      > with the motor, then drive it using your wide-open power supply (no
                      > controller) and measure the current under the expected torque load.
                      This
                      > will tell you how powerful your controller must be.
                      >
                      > Many controllers will allow you to gang their output channels
                      together
                      > to provide more drive capacity. I don't know about the Hobby
                      Engineering
                      > unit that you are using. Perhaps someone else could contribute here?

                      The two channels of the L298 can be "paralleled" according to the
                      datasheet (http://www.st.com/stonline/books/pdf/docs/1773.pdf - see
                      fig 7). The paralleled configuration gives a max current of 3A. I'm
                      not sure if this will be enough for your motor though. You should
                      measure the current your motor draws under the required load as
                      Stephen and Branden suggested.






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                    • haqmaq
                      Do you have a link or the actual datasheet on this motor? That would help in finding a quick answer to your question. Typically, you want to size motor
                      Message 10 of 11 , Feb 28, 2007
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                        Do you have a link or the actual datasheet on this motor? That would
                        help in finding a quick answer to your question. Typically, you want
                        to size motor controllers for the max current (really you'd want a
                        little more) that your motor can draw.

                        There are a few sanity checks you may want to go through. First,
                        connect a tiny DC motor and see if that runs. If not, then you have
                        other problems to solve first.

                        -zboot


                        --- In SeattleRobotics@yahoogroups.com, "Victor" <sluggo55555@...> wrote:
                        >
                        > I'm not certain what the start up current is for this motor but it is
                        > rated at .91 amps on the low speed I'm sure that is continuous and I
                        > have no idea what the start up current is. do you suppose I could
                        > double the output by ruining both sides at once or can someone point
                        > me to a controller that's stronger?
                        >
                      • Mack Mack
                        IANAEE but I ve read that some motor controllers can t supply enough peak current or don t have a fast enough turn on time for driving power mosfets
                        Message 11 of 11 , Feb 28, 2007
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                          IANAEE but I've read that some motor controllers can't supply enough peak current or don't have a fast enough turn on time for driving power mosfets effeciently. So depending on the output frequency load and your motor driver, you might end up destroying the mosfets.....


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