Bilbrey09 Report post Posted June 5, 2020 I have a Juki DNU-421H with a clutch motor. I want to upgrade to a servo motor and needle synchronizer/positioner. Would appreciate recommendations on brands and where to buy here in the USA. Thanks! Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted June 5, 2020 1 hour ago, Bilbrey09 said: I have a Juki DNU-421H with a clutch motor. I want to upgrade to a servo motor and needle synchronizer/positioner. Would appreciate recommendations on brands and where to buy here in the USA. Thanks! This is a servo motor that can run so slowly that you won't need a needle positioner. If the motor alone doesn't spin the machine slow enough, the speed reducer lower down the page will. I have 3 machines equipped with this motor and a speed reducer. They can run so slow it's like watching grass grow. If I increase the speed setting knob to the maximum I can get about 5 or 6 stitches per second. One of my walking foot machines is fed directly from the same motor, which has a 2" pulley. It can easily poke along at about 1.5 or 2 stitches per second with the speed knob turned down low. I can easily stop it on a dime! When I max out the knob it flies at about 15 stitches per second. I hope this helps. Quote Share this post Link to post Share on other sites
Bilbrey09 Report post Posted June 11, 2020 On 6/5/2020 at 1:10 AM, Wizcrafts said: This is a servo motor that can run so slowly that you won't need a needle positioner. If the motor alone doesn't spin the machine slow enough, the speed reducer lower down the page will. I have 3 machines equipped with this motor and a speed reducer. They can run so slow it's like watching grass grow. If I increase the speed setting knob to the maximum I can get about 5 or 6 stitches per second. One of my walking foot machines is fed directly from the same motor, which has a 2" pulley. It can easily poke along at about 1.5 or 2 stitches per second with the speed knob turned down low. I can easily stop it on a dime! When I max out the knob it flies at about 15 stitches per second. I hope this helps. Definitely helps! I did not realize there was an option like this. Thanks for the information! Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted June 11, 2020 3 hours ago, Bilbrey09 said: Definitely helps! I did not realize there was an option like this. Thanks for the information! My first servo motors were brush-less and started with a jerk at either 100 or 200 rpm. To this very day there are still a lot of brush-less servos that do the same as before. On the other hand, all of the brush servos I've had start spinning from zero and increase gradually to whatever maximum speed has been set on its knob (pot or switch). Quote Share this post Link to post Share on other sites
greenbean Report post Posted June 13, 2020 On 6/5/2020 at 12:10 AM, Wizcrafts said: This is a servo motor that can run so slowly that you won't need a needle positioner. If the motor alone doesn't spin the machine slow enough, the speed reducer lower down the page will. I have 3 machines equipped with this motor and a speed reducer. They can run so slow it's like watching grass grow. If I increase the speed setting knob to the maximum I can get about 5 or 6 stitches per second. One of my walking foot machines is fed directly from the same motor, which has a 2" pulley. It can easily poke along at about 1.5 or 2 stitches per second with the speed knob turned down low. I can easily stop it on a dime! When I max out the knob it flies at about 15 stitches per second. I hope this helps. Can I ask if you are using the box-style reducer or the SR-2 with your machines?... Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted June 14, 2020 6 hours ago, greenbean said: Can I ask if you are using the box-style reducer or the SR-2 with your machines?... I have a box reducer on my Singer 168 post machine. My Techsew 2700 has a 2:1 wheel reducer that came with it. My Cowboy CB4500 has a 3:1 wheel reducer. All of these have Family Sew motors. Quote Share this post Link to post Share on other sites
George1520 Report post Posted June 14, 2020 For speed control only have two choices the one that has been already mentioned, a dc motor with a brake and the other kind, a step motor that can use a needle positioning. People call them servo motors but they are not. Sewing machine servo motors are huge and bigger much than a clutch motor. Quote Share this post Link to post Share on other sites
Gymnast Report post Posted June 15, 2020 I made a collection of nine videos from youtube on the topic of speed control. You may find it insteresting. https://www.youtube.com/playlist?list=PLhBGyDo4tov8XSL24b3eiAsGBhlPJA2SF You may just skip a video if you do not find it interesting. I have got a Bernina 910 domestic sewing machine, that I occationaly use for some garment. But I do not like the speed control, because when I press slowly down the pedal, I do not know when it will start sew, and suddently it starts. Some of my other machines makes some hum noise before it starts, and it is actually nice, because then you are prepared for when the sewing starts. Quote Share this post Link to post Share on other sites
