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Makita Impact with Brushless Motor

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  • Makita Impact with Brushless Motor

    Anyone seen this yet?

    http://www.toolstop.co.uk/makita-btd...er-naked-p6822

    Reminds me of the Panasonic that came out a while ago. I've been wondering for quite a while why tool companies have not adopted brushless motors more often. I guess they cost more because you need more complicated electronics to control the commutation, but the benefits are great, especially in terms of efficiency.

  • #2
    Re: Makita Impact with Brushless Motor

    Efficient brushless cost a lot more than equivalent torque brushed, under high load they get very hot which might cause damage to rotor magnet and plastic casing around the stator. Also, under high loads brushed motors catch up with efficiency.

    Comment


    • #3
      Re: Makita Impact with Brushless Motor

      Actually it's the other way around. In a brushless motor, it's easier to get the heat out because the coils are on the outside on the motor. And on the outside, you've got more surface area to dissipate the heat.

      Brushless also lends itself to doing a TEFC, totally enclosed fan cooled, design which would be a big plus for a tool like a grinder. Concrete dust and debris is hell on an open motor, because it tends to blast the varnish off the wires.

      Then you throw in that you can do all kinds of useful speed and torque controls since you have to have an electronic controller anyway.... the advantages are numerous, except for cost. But I wouldn't be surprised if that cost has come down quite a bit in recent years.

      Originally posted by DRC-Wartex View Post
      Efficient brushless cost a lot more than equivalent torque brushed, under high load they get very hot which might cause damage to rotor magnet and plastic casing around the stator. Also, under high loads brushed motors catch up with efficiency.

      Comment


      • #4
        Re: Makita Impact with Brushless Motor

        Sceeter, in power tools the motor will be encased and thus your point about surface area is moot because it will be insulated. You can stick a heatsink around it but it has to be huge to cool passively. Instead, cordless tools with brushless motors use forced air cooling with open body just like brushed ones (Look at Panasonic EY7540LN2S), which makes them also vulnerable (thanks for explaining about abrasive dust, after using, selling and repairing power tools for 10 years, I would have never guessed). Also electronic components can fail due to temperature cycling. I can also tell you the cost of motors, Dewalt's motor from DC925 is $27 and Panasonic's is ~$47 USD, so difference is negligent compared to a cost of average kit. Brushed motors in grinders have windings covered in epoxy or ceramic-like compounds that protect them from dust (Bosch for example).

        Brushless have flaws that are more important than price and that's why they are not widely adopted in tools.

        I also recommend to not correct somebody unless you know what you are talking about. Thank you, try again.

        Comment


        • #5
          Re: Makita Impact with Brushless Motor

          Uh yeah right, which would explain Bosch's latest Litheon rotary hammer has an enclosed brushless motor:

          http://www.ereplacementparts.com/bos...7959615777dac9

          Oh, and is that a fan on the back??

          http://www.amazon.com/Bosch-11536C-1...0033601&sr=8-2

          But anyway, in the future Bosch, Makita, and Panasonic should stop and consult with you first, because you clearly know better. Soon they will have to recall all those melted housings and overheated armatures. Maybe they will send them to your "shop" for repairs.

          Oh and you were clearly right about Milwaukee discontinuing V28, which of course is why the full V28 line is still included on their new website:

          http://milwaukeetool.com/

          As you can see, they followed your advice that their batteries are "not suitable for power tool use" and got rid of that line post-haste.

          Thanks man, you really saved them from that flop waiting to happen! If only you could have told them that in 2005

          Originally posted by DRC-Wartex View Post
          Sceeter, in power tools the motor will be encased and thus your point about surface area is moot because it will be insulated. You can stick a heatsink around it but it has to be huge to cool passively. Instead, cordless tools with brushless motors use forced air cooling with open body just like brushed ones (Look at Panasonic EY7540LN2S), which makes them also vulnerable (thanks for explaining about abrasive dust, after using, selling and repairing power tools for 10 years, I would have never guessed). Also electronic components can fail due to temperature cycling. I can also tell you the cost of motors, Dewalt's motor from DC925 is $27 and Panasonic's is ~$47 USD, so difference is negligent compared to a cost of average kit. Brushed motors in grinders have windings covered in epoxy or ceramic-like compounds that protect them from dust (Bosch for example).

          Brushless have flaws that are more important than price and that's why they are not widely adopted in tools.

          I also recommend to not correct somebody unless you know what you are talking about. Thank you, try again.

          Comment


          • #6
            Re: Makita Impact with Brushless Motor

            Now now fight nicely guys
            9/11/01, never forget.

            Comment


            • #7
              Re: Makita Impact with Brushless Motor

              You guys need to treat each other with respect and agree to disagree.

              Thanks-Mark
              "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

              I never lost a cent on the jobs I didn't get!

              Comment


              • #8
                Re: Makita Impact with Brushless Motor

                Originally posted by oldslowchevy View Post
                Now now fight nicely guys
                Originally posted by ToUtahNow View Post
                You guys need to treat each other with respect and agree to disagree.

                Thanks-Mark
                Well said, well said.

                Comment


                • #9
                  Re: Makita Impact with Brushless Motor

                  I do know that they have been using brushless motors and their associated electronics in rc airplanes and rc race cars and have had tremendous success with them. Off road rc car racing is very hard on electric motors and they aren't having any issues with them. Run times are much, much better then the brushed motors. They are completely sealed with just a heat sink on the endbell.

                  Comment


                  • #10
                    Re: Makita Impact with Brushless Motor

                    There was an impact driver review from Tools of the Trade:

                    http://www.toolsofthetrade.net/indus...05143&artnum=5

                    Notice that their 14.4V 3AH brushless impact drives 20-30 more lags than a great deal of the 18V units.

                    Comment


                    • #11
                      Re: Makita Impact with Brushless Motor

                      hmmm
                      Last edited by Kanxrus; 09-24-2009, 11:04 PM.

                      Comment


                      • #12
                        Re: Makita Impact with Brushless Motor

                        You get what you pay for to a point. Sometimes money is paid for the label on the product.

                        Brushless motors seem to be the way of the future for some tools. Unless they fail completely it seems to be the future.

                        Comment

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