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toxo

Slowing down my servo.

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I may have asked before and got no answer.

The servo on my Adler 69 starts at 16 and goes up to41.  I can't get it any lower.I've got it somewhere near where I want it by putting a 40mm pulley on it but it still catches me out sometimes. If I can't get a solution I'll probably replace the hand wheel with a large pulley. Anyone got a manual please?

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14 minutes ago, Danne said:

Not same brand name, but same model number so I guess it's the same servo

http://www.jegon.com/upload/ueditor/file/20181222/15454620994420286.doc

http://www.jegon.com/en/products/46.htm

That's great Danne, thank you. Unfortunately I can't see an answer to my problem. I already know how to change the speed but it just won't go lower than sixteen. On my other machine (different servo) it starts at 1.

I've sent an email but not holding my breath.

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22 minutes ago, toxo said:

That's great Danne, thank you. Unfortunately I can't see an answer to my problem. I already know how to change the speed but it just won't go lower than sixteen. On my other machine (different servo) it starts at 1.

I've sent an email but not holding my breath.

In the manual it talks about two modes, one low speed mode.

And here I see the same model number and "0-5000 RPM Adjustable Speed Control"

https://www.tokopedia.com/ptsams/dinamo-mesin-jahit-industri-550watt-mtr-energy-saving-servo-motor

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9 minutes ago, Danne said:

In the manual it talks about two modes, one low speed mode.

And here I see the same model number and "0-5000 RPM Adjustable Speed Control"

https://www.tokopedia.com/ptsams/dinamo-mesin-jahit-industri-550watt-mtr-energy-saving-servo-motor

The slower of the two modes starts slower but to be honest I don't see much difference between the two modes.

I'm not sure of the slowest speed at what would be No1 but the speed goes up by 100 for each increase thus No50 equates to 5000. Mine starts at 16 but I've installed a 40mm pulley so god knows what speed it's doing. Both speed modes will use whater No is selected.

I'm beginning to feel like a dog with a bone. I can do a stitch at a time if I'm careful and I think some foam under the pedal or a spring/bungee will cut down the surprises. At the moment I'm frightened to put my foot on the treadle if there's any work under the needle.

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all motors start 0 RPM (of course) question is what is the next step. Most servos start working between 100 and 200 rpm - I guess 16 mean 160 rpm and 1 means 100 rpm

I would add a speed reducer 1:3 speed reducer. I added SR´s to ALL my machines - its just gives you a much better speed control. A larger hand wheel / pulley on the machine is another option but to be honest I do not like that just for optical reasons but that's just me.

DIY speed reducers are cheap you just need a 40 - 50mm pulley, a 120 - 150mm pulley, ~100 - 150mm long 15mm diameter shaft, 2 pillow block bearings, some scrap wood and some screws... Should be doable for approx 25 - 40 bucks (depends on your market and currency) .

This is my DIY reducer I put on my 51w post bet set up.

 

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Edited by Constabulary

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1 hour ago, Constabulary said:

all motors start 0 RPM (of course) question is what is the next step. Most servos start working between 100 and 200 rpm - I guess 16 mean 160 rpm and 1 means 100 rpm

I would add a speed reducer 1:3 speed reducer. I added SR´s to ALL my machines - its just gives you a much better speed control. A larger hand wheel / pulley on the machine is another option but to be honest I do not like that just for optical reasons but that's just me.

DIY speed reducers are cheap you just need a 40 - 50mm pulley, a 120 - 150mm pulley, ~100 - 150mm long 15mm diameter shaft, 2 pillow block bearings, some scrap wood and some screws... Should be doable for approx 25 - 40 bucks (depends on your market and currency) .

This is my DIY reducer I put on my 51w post bet set up.

 

IMG_1467.JPG

IMG_1509.JPG

IMG_1469.JPG

LOL

Thanks for the definition ,  What you call a speed reducer,  And that is EXACTLY what it is

I call a Jack shaft with a slave pulley  

See the source image

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My feeling with those type of servos has been the same as yours... almost satisfied.  

I switched to a simple servo with one manual knob to control the speed, and a box style speed reducer mounted between the table and motor.  Steady stitch at a time, with no lurching or jumping.  Plus it could probably sew through plywood.  

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1 hour ago, Frodo said:

I call a Jack shaft with a slave pulley  

Speed reducer is the common term here for the above and similar constructions.

 

55 minutes ago, Pintodeluxe said:

My feeling with those type of servos has been the same as yours... almost satisfied.  

You get what you pay for ;)

I would not pay big $ for a high end servo (like EFKA) cause I just do not have the out put that would justify this investment. The "cheap servo" and speed reducer combo works very well for what I´m doing. I´m very pleased with what I have.

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To be fair, the speed of the Adler isn't far away from what I want because I've already installed a 40mm pulley on the servo. I think I will replace the hand wheel for a bigger pulley. I put a 170mm pulley on the Durkopp 239 along with a 75mm pulley on the motor which gives me good speed and control and more torque than the Adler.

I think my biggest problem with the Adler at the moment is the control. It's been put to the front of a Singer table and getting close to the action meant that I was inadvertently putting more weight on the toe and the balance was such that it would suddenly start and frighten the life out of me. I moved the treadle forward slightly but I can't counterbalance the weight of the treadle. I will add springs/bungees to the forward edge of the thing until I get it tamed.

Folker, I appreciate what you're saying and of course, each to his own but for me a car is for getting from A to B not spending hours polishing it. Those SR gizmos are way too much faff for me. A pulley and taperlock bush will probably cost around £20/£25, Will give me the speed I want, and because it has more mass will be slightly slower to get going and give more torque. It will be easier to "handwheel" and will take minutes to fit excluding any alterations to the EPS infrastructure.

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I'm with Constab. I've fitted speed reducers (home-made and all different) and/or larger pulleys in lieu of handwheels to all of my machines and it gives me all the control I want. They compensate for the inadequacies of cheap/generic servos.

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I have tried to look in more servo motor specifications, and I think it is hard to find what the lowest constant speed is. Normally you cannot find it or it is hidden very well. I guess it is because leatherworkers and other users seldom ask for this specification. Sometimes the machine got a ramp up function from start, but it do not help much. Perhaps most servo motors are designed for garment high speed machines, that do not need a bigger variation in speed.

Normally the display shows the speed as Costabulary write. But I should think that 41 should mean 4100 RPM and 16 should mean 1600 RPM. But in general you do not know how these numbers translate to RPM. If the lowest speed is 1600 RPM, it is a very high low speed, and I newer heard of that before. Something could be wrong as reported in this video from 2012:

https://youtu.be/X6CCxv3i4No

This problem was discussed in more threads of this forum back 2012. This is one of them: 

I use my domestic sewing machine for many different jobs, and it have got a DIY speed control with a factor of about 68 between highest and lowest speed. Furthermore the construction of the pedal make a fast and easy control of speed:

https://youtu.be/uTB8DnyYAlA

 

I think it would be no problem for a servo motor manufacturer to make a similar speed control with very limited extra costs, if they got the demand for it.

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6 hours ago, Gymnast said:

I have tried to look in more servo motor specifications, and I think it is hard to find what the lowest constant speed is. Normally you cannot find it or it is hidden very well. I guess it is because leatherworkers and other users seldom ask for this specification. Sometimes the machine got a ramp up function from start, but it do not help much. Perhaps most servo motors are designed for garment high speed machines, that do not need a bigger variation in speed.

Normally the display shows the speed as Costabulary write. But I should think that 41 should mean 4100 RPM and 16 should mean 1600 RPM. But in general you do not know how these numbers translate to RPM. If the lowest speed is 1600 RPM, it is a very high low speed, and I newer heard of that before. Something could be wrong as reported in this video from 2012:

https://youtu.be/X6CCxv3i4No

This problem was discussed in more threads of this forum back 2012. This is one of them: 

I use my domestic sewing machine for many different jobs, and it have got a DIY speed control with a factor of about 68 between highest and lowest speed. Furthermore the construction of the pedal make a fast and easy control of speed:

https://youtu.be/uTB8DnyYAlA

 

I think it would be no problem for a servo motor manufacturer to make a similar speed control with very limited extra costs, if they got the demand for it.

Yes, I believe 1600 would be too fast for me but I've brought the speed down some by fitting the 40mm pulley. It's still a little too fast so I'll be taking a trip to the pulley shop soon for a replacement hand wheel. I might go as big as 250mm. I know it's a bit sticky outy with no guard on it but there's only me and the dogs here and the dogs can't reach. Have to cut a longer slot for the longer belt and move the bobbin winder but I think it'll be worth it. I'll still have up to No 41 if I want a bit more speed.

I don't Know if  the Jack motors have the gradient thing in em. I'll check before I do anything drastic.

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Personally, I think those numbers that are quoted in the manuals are pretty meaningless, just something they come up with to sound impressive! You have to experiment with the settings and various pulleys to get something that works for you.

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I've just ordered a 250mm pully with the corresponding taperlock bush with a 15mm bore. Total cost inc vat =£23+ the new belt. The only variable is the size of the new belt. I'm aware that if I could get the servo to start at 1 instead of 16 I wouldn't need such a big pulley but I can always change the size of the pulley and use the same taperlock bush. Another factor in going for a big pulley is weight. I might even add more weight to make up for the heavy factory handwheel.

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Update. Turns out the shaft on my Adler is 14mm not 15mm so will be exchanging the taperlock bush later. Also the center set screw that holds the nylon bush for the synchroniser isn't long enough for the thickness of the bigger pulley but it looks like College Sewing has that covered with a kit. I did bodge it together with a torx bit in the keyway and a leather strip for a belt andthe result looks really good. I'll try to do a video when It's done. 

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Another update.

Pulley now secure but belt too small, changing it tomorrow. Made a leather one to test.

https://youtu.be/fCRqWdEqTeM

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20 hours ago, toxo said:

Another update.

Pulley now secure but belt too small, changing it tomorrow. Made a leather one to test.

https://youtu.be/fCRqWdEqTeM

When I you see max speed in the video, is it with the pedal pressed to max speed? Is the max speed limited by a setting?

It seems to me, that the lowest speed is about 1 stitch per second and max speed is about 3 stitch per second.

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1 hour ago, Gymnast said:

When I you see max speed in the video, is it with the pedal pressed to max speed? Is the max speed limited by a setting?

It seems to me, that the lowest speed is about 1 stitch per second and max speed is about 3 stitch per second.

You set the speed on the panel. The pedal then gives you from zero to max . In the video the set speed was the lowest I can get it which was 16. On that setting I can stop at half a stitch. If I set the speed to 41 (the highest it will go) the machine will still go from zero to max but at a faster rate.

Finished the fettling today. Put on the new belt but had to extend the slot in the table. Had to make a new bracket for the needle synchroniser because of the bigger diameter of the pulley but all done now. I know it's gonna be a joy to use now once I attempt to fine tune it. :)

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