Constabulary Report post Posted April 13, 2014 (edited) I recently bought a 400Watts Servo with needles positioning system. Its not a common brand you find in the US I think. It is an analog servo with magnetic speed regulation. Overall a nice motor but the needles positioning system (NPS) sucks! Problem is sometimes the needle positioning system makes 1 stitch too much. Needle goes down and you think it will stay there but then it makes another stitch. This is pretty annoying when you sew short seams on straps or so. No way to adjust the sensor on the hand wheel. I tried it over and over again. Furthermore if the needle hits a hard point the positioning system does not turn off even when I take the foot off the pedal. it always works against the hard point. So the only way is to turn off the entire motor. I don´t like it at all! So I wonder if I can run the ENDURO Servo motors (or clones) which are equipped with a NPS without the NPS. I know I can get them without NPS but I want to know if I pull the plug of the hand wheel sensor just for the case I don't want to use the NPS "today" does the motor still work or does it produce a failure? Also, do other motors with NPS turn off when they hit a hard point? Edited April 13, 2014 by Constabulary Quote Share this post Link to post Share on other sites
gottaknow Report post Posted April 13, 2014 The motor will not function. And yes, the needle positioner has no clue what you're sewing, so it will always try to position regardless. Depending on the control box, if the needle can't finish it's positioning, it will give an error and have to be turned off, then back on, or blow a fuse. ps. Did you ever get that other info I mailed sometime back? Regards, Eric Quote Share this post Link to post Share on other sites
Constabulary Report post Posted April 14, 2014 (edited) Thanks Eric! Is that the case on ALL servos with NPS (or EPS)? I wonder if I´m the only one who has this problem. I do not sew very heavy leather but sometimes quite thick canvas straps. I wonder if the guys who make holster from heavy leather have this problem too. Men - this sucks so bad... How is it with this "one stitch too much" - is this a known problem? Because of the info you sent by mail - no, it honestly has never arrived. But don´t send them again because my pal kicked out his motor and bought a used Pfaff clutch motor. Edited April 14, 2014 by Constabulary Quote Share this post Link to post Share on other sites
gottaknow Report post Posted April 14, 2014 (edited) From what you describe, you're blaming the wrong component. It's the motor itself that's letting you down, not the positioning system. All the positioner does is signal the motor where to start and stop. If the work is heavy enough, the motor doesn't have enough power to position the needle to the down position. If it fall short, you get a motor failure error and it has to be reset. If this is what happens, you need a speed reducer to give your motor more torque. Oh, and the extra stitch issue is a result of the motor working really hard to push your needle through, and when it finally makes it, it surges past your stop point because of the extra momentum and thinks you've pushed the pedal again so it goes to the next stopping point, giving you an extra stitch. Lots of servo motors do this when over-worked. Even the air-gap motors like the older Variostops have the same problem. Regards, Eric Edited April 14, 2014 by gottaknow Quote Share this post Link to post Share on other sites
Constabulary Report post Posted April 14, 2014 Thats possible! I´m currently working on 2 speed reducers but anyway - I still have the issue with the extra stitch when the motor is positioning the needle. So sewing just 1 stitch is not possible with this motor. It at least makes 1 stitch too much and sometimes even 2! I decided kick out this motor and look for another one. I´m thinking about one (or two) of the Enduros + my Speed reducer. They have more Watts and a good reputation too, plus I even can order spare parts online. So I wanted to check if the Enduros also have this "1 stitch too much" issue that my motor has. Quote Share this post Link to post Share on other sites
Constabulary Report post Posted April 14, 2014 (edited) BTW - the extra stitch happens on light fabric as well not only on heavy material. I first thought it is because of the compound feed of my 111G156 but I now have mounted it to a different machine with regular feed and the problem is still the same. Here is a short video - you see what I mean? http://s351.photobucket.com/user/orangeagentz/media/sewing_vids/MOV001.mp4.html EDIT: For those who find this post randomly and think it is an ENDURO motor - IT IS NOT!!!! Edited April 14, 2014 by Constabulary Quote Share this post Link to post Share on other sites
gottaknow Report post Posted April 15, 2014 Wow. I'm thinking you have a bad synchronizer. If your synchronizer has the slots in the wheels for adjusting the needles down position, make the opening a little wider so the sensor knows it's time to stop. Regards, Eric Quote Share this post Link to post Share on other sites
Constabulary Report post Posted April 15, 2014 I even have 2 synchronizers. I wanted one on each machine so I can switch the machines on my table and can use one motor (saves me space) but both synchronizers have the same issue. I tried to adjust the synchronizers back + forth but no change at all. So I think this is not a common issue, right? Or have you ever heard of this before? I ask because I don´t want to deal with this issue again in case I´m buying an Enduro motor or a clone. Quote Share this post Link to post Share on other sites
Cobra Steve Report post Posted April 15, 2014 Hello. On our servo motors, if you take your foot off of the pedal as the needle is on the upstroke, then it will finish the cycle and give you the extra stitch. If you take your foot off of the pedal ,as the needle is on the down stroke, it will just finish that stitch only. It takes a little timing, but the machine is going slow enough to get used to it. Steve P.S. Hi Eric, hope all is well. Quote Share this post Link to post Share on other sites
Constabulary Report post Posted April 15, 2014 Hi Steve - thanks for your reply. Yes, thats how I would expect the NPS should work but as you see in the last seconds of my video, the needle is on the down stroke and goes down a bit slow already but then when it was down already it makes another stitch... Quote Share this post Link to post Share on other sites
Cobra Steve Report post Posted April 15, 2014 Are there any other functions on your control panel, like thread trimmer, or automatic foot lift? Steve Quote Share this post Link to post Share on other sites
Constabulary Report post Posted April 16, 2014 No, this is a very basic motor with just on / off switch and a switch for rotation direction. No control panel at all. Well, this motor has to go anyway. I just wanted to be sure that other servo motors like the Enduros do not have this issue. Quote Share this post Link to post Share on other sites
Constabulary Report post Posted April 17, 2014 Wow. I'm thinking you have a bad synchronizer. If your synchronizer has the slots in the wheels for adjusting the needles down position, make the opening a little wider so the sensor knows it's time to stop. Regards, Eric I opened the sensor and figured it uses magnet for the positioning signal. Thought I don't keep the motor, I will try to set the disc with the magnets closer to the sensors. If I ruin the sensor I have one spare so its worth the try. Some pics. Quote Share this post Link to post Share on other sites
gottaknow Report post Posted April 18, 2014 Ah. The magnetic sensors. Vibration kills magnetism over time. Take a small rare earth magnet and place on each magnet for a period of time. Say 30 minutes. I have re-energized magnets in synchronizers this way in the past. Give it a try. Regards, Eric Quote Share this post Link to post Share on other sites
Constabulary Report post Posted April 18, 2014 Holy Cow - thats a good idea. I will try some neodym magnets. I think I have some floatings around here. Bringing the disc closer to the sensor did not work. Quote Share this post Link to post Share on other sites
Tom Spivak Report post Posted April 18, 2014 I just purchased a sew-quite 5000 nps and was having similar problem, extra stitch, and refused to stop at the top. Reliable took it back, I had it returned no charge 3 days and works perfect on any weight material. Maybe you just have a bad unit? Quote Share this post Link to post Share on other sites
Constabulary Report post Posted April 19, 2014 Eric, "reconditioning" the magnets did not work. I even tried to leave the neodym magnets in the sensor - no change at all. Quote Share this post Link to post Share on other sites
Tom Spivak Report post Posted April 19, 2014 Once again, if you are within the warranty period I would contact the place you purchased the motor from and have them check it out. Even if you are not in warranty, why not call them and get their advice? Good Luck. Quote Share this post Link to post Share on other sites
gottaknow Report post Posted April 20, 2014 If you've tried 2 different synchronizers, it's got to be the stop function on the motor or the control box. I do know on the Varistop units, a poor electrical connection or plug socket issue will do this. On my Juki 5410's, oil migrates from the sump pans, down the foot lift rod, right on top of the control boxes. I've started using silicone to seal the cover plates for the electrical connections. Oh, and you get what you pay for with these units. Just saying. Regards, Eric Quote Share this post Link to post Share on other sites
Trox Report post Posted April 21, 2014 Hi Constablery, I would demand my money back for such dangerous motor. Its a very easy to stitch true your fingers. Its clearly a construction fault, it's not doing what it's supposed to do. Good luck Tor Quote Share this post Link to post Share on other sites