Members Constabulary Posted November 10, 2014 Author Members Report Posted November 10, 2014 I think TROX or someone else explained in in an other thread, it is because of the belt slippage as far as I remember. I don´t know for sure if other sewing machines / other servos with NPS wok with speed reducers but my experience is that the Jack Servos do not! I´ll try to find the thread... When I look at the Cobra 4 and Cowboy 4500 it seems these machines also come w/o an NPS and both have speed reducers so I don´t know. I think it is a general issue when you are using speed reducers but I´m not sure... Quote ~ Keep "OLD CAST IRON" alive - it´s worth it ~ Machines in use: - Singer 111G156 - Singer 307G2 - Singer 29K71 - Singer 212G141 - Singer 45D91 - Singer 132K6 - Singer 108W20 - Singer 51WSV2 - Singer 143W2
Members Constabulary Posted November 10, 2014 Author Members Report Posted November 10, 2014 (edited) Here is the thread: http://leatherworker.net/forum/index.php?showtopic=56955&p=365941 @VanRhodes Maybe it is different with your machine as far as I remember you have a fixed gear reduction mounted on your machine so there is no belt slippage... but I don´t know for sure. Just a guess. Edited November 10, 2014 by Constabulary Quote ~ Keep "OLD CAST IRON" alive - it´s worth it ~ Machines in use: - Singer 111G156 - Singer 307G2 - Singer 29K71 - Singer 212G141 - Singer 45D91 - Singer 132K6 - Singer 108W20 - Singer 51WSV2 - Singer 143W2
Members VanRhodes Posted November 10, 2014 Members Report Posted November 10, 2014 Constabulary: I see. I do recall Trox mentioning that the NPS for the Efkas were there to calculate belt slippage, but as far as I can tell the NPS for the Jack Servos use indicators on the drive shaft/pulley to indicate the needle up and down positions, thus any reducers in between the motor and the machine should be irrelevant to the function of the NPS since one revelation of the drive shaft equals one cycle of the machine no matter how many rpms the motor is doing. Atleast thats the way I have understood it. No matter what, the price for the NPS addon to the Jack motor is cheap so its not that much of a loss if it doesnt work. Yes, I have fixed gear reduction and the additional reduction I am building has a timing belt with tooths as well. a Quote
Members Bertil Posted November 10, 2014 Members Report Posted November 10, 2014 My experience re. servomotors is from the packaging industry. The advantages with a servomotor compared to the normal electrical motor is that you can control: acceleration, speed, retardation and the exact position of the drive shaft. This should come in handy in a sewing machine. Obviously there are a lot of servos adapted for industrial sewing machines that don´t have these features. Since most sewing machine have belt drives you have to measure the rotation on the drive shaft. To calculate belt slippage is long term impossible. It will change over time and depend on the material you are sewing. It would also be nice to be able to control the acceleration on a sewing machine. Anyone knows a servo with that feature? Quote
Members Constabulary Posted November 11, 2014 Author Members Report Posted November 11, 2014 @VanRhodes I´m no scientist or electric engineer. All I can say is that it worked w/o the speed reducer and is not working after I added the speed reducer. That is m experience so far. I would make a video with and without the reducer but the belt cannot reach the motor pulley. I bought the 750Watts motor with NPS and the 550Watts w/o NPS. I will try if the NPS works with the 550Watts motor when I´m puzzling on my setup next time but that may take a few weeks. Quote ~ Keep "OLD CAST IRON" alive - it´s worth it ~ Machines in use: - Singer 111G156 - Singer 307G2 - Singer 29K71 - Singer 212G141 - Singer 45D91 - Singer 132K6 - Singer 108W20 - Singer 51WSV2 - Singer 143W2
Members VanRhodes Posted November 11, 2014 Members Report Posted November 11, 2014 Constabulary, thanks! Since the NPS isnt very expensive at all I'll just order one along with additional needles and parts when I do my next order, I will also get back with feedback on how and if its working. Quote
Members Constabulary Posted November 11, 2014 Author Members Report Posted November 11, 2014 Sounds good. Maybe I´m just to dumb - you never know Quote ~ Keep "OLD CAST IRON" alive - it´s worth it ~ Machines in use: - Singer 111G156 - Singer 307G2 - Singer 29K71 - Singer 212G141 - Singer 45D91 - Singer 132K6 - Singer 108W20 - Singer 51WSV2 - Singer 143W2
Members Bertil Posted November 11, 2014 Members Report Posted November 11, 2014 Constabulary post 9: I believe the "beeeeeeeeep" machine comes from this supplier: http://www.hmcmotor.com.cn/website/enproduct_list.asp?action=product&YGH=LookProduct&Product_Id=49&CPclass_Id=1 Quote
Members kolb Posted November 24, 2014 Members Report Posted November 24, 2014 Could you tell me the size of the pulley shaft ? Is it the 15mm straight bore with key ? And did it come with a UK plug terminal? Thanks Quote
Members Constabulary Posted November 24, 2014 Author Members Report Posted November 24, 2014 It came with a UK plug but it´s easy to replace and the straight bore is 13mm. Quote ~ Keep "OLD CAST IRON" alive - it´s worth it ~ Machines in use: - Singer 111G156 - Singer 307G2 - Singer 29K71 - Singer 212G141 - Singer 45D91 - Singer 132K6 - Singer 108W20 - Singer 51WSV2 - Singer 143W2
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