my new consew 206RB-5 premier 550 variable speed servo motor-speed control

[wydfuqnopn]

Just bought this machine and love it. Would ultimately like a cowboy 105 too but could only afford one or the other. I bought it for the range of sewing it will do. I will be using it primarily for belts, purses, wallets, briefcases, etc. nothing really above 8-9 ounce leather. but occasionally for applications where I will appreciate its speed. I also bought the 50mm pulley for the motor from consew.

Here is my question that I will appreciate anything you can offer.

How slow can I get it down to?

can you recommend that I use a gear reducer or a larger pulley system underneath?

is there a "monster wheel" or something of the sort for the actual "head" that I can use in conjuction with the 50mm to accomplish a slower speed without having to use a gear reducer or larger pully system underneath?

Thank you in advance. im new to all this sewing stuff with a machine. Been doing it all with two needles and thread up until now.

 

Best regards,

steve

 

 

 

 

 

 

[katit]

Steve, I have same motor on my Pfaff 1245. With original 75mm pulley it was little too fast for me. With 45mm pulley it is much better. Keep in mind I'm learning too, so it may not be a problem to someone with experience. To me - this one change is good enough, but I'm working on upholstery stuff. For small items like you mentioned I would probably think about reducer, but again, I think this is 95% experience and 5% motor reducer

Edited November 5, 2018 by katit

[Pintodeluxe]

Work with your current setup for a bit.  If it's slow enough for you, then your're good to go.  If you need more slow-speed control you can always add a speed reducer.  

[dikman]

Simplest way is to find a large pulley to replace the handwheel, an 8" will give a significant speed reduction (I've done this on three of my machines). There have been a few posts about this method as well as lots about speed reducers.

[wydfuqnopn]

5 hours ago, katit said:

Steve, I have same motor on my Pfaff 1245. With original 75mm pulley it was little too fast for me. With 45mm pulley it is much better. Keep in mind I'm learning too, so it may not be a problem to someone with experience. To me - this one change is good enough, but I'm working on upholstery stuff. For small items like you mentioned I would probably think about reducer, but again, I think this is 95% experience and 5% motor reducer

I haven't actually installed the 50mm pully yet because I wanted to use it as it came before changing it so that I could recognize the difference. thank you for help

[wydfuqnopn]

3 hours ago, dikman said:

Simplest way is to find a large pulley to replace the handwheel, an 8" will give a significant speed reduction (I've done this on three of my machines). There have been a few posts about this method as well as lots about speed reducers.

ok so I have seen the you tube video but I have talked to 3 different people who work for companied selling the machines and they all said that it would possibly harm the machine but they hadn't done it themselves so couldn't give me reasons why. I know there are plenty of manufacturers who make a larger wheel for their machines and works without damaging the unit. I actually bought a pulley before talking to them and decided to just do it the established method. My pulley didn't have any places for screw to go into the bore so returned it. Bye would like a bigger handwheel anyway. Thx for input

can you recommend where to buy one?

[R8R]

1 hour ago, wydfuqnopn said:

ok so I have seen the you tube video but I have talked to 3 different people who work for companied selling the machines and they all said that it would possibly harm the machine but they hadn't done it themselves so couldn't give me reasons why. I know there are plenty of manufacturers who make a larger wheel for their machines and works without damaging the unit. I actually bought a pulley before talking to them and decided to just do it the established method. My pulley didn't have any places for screw to go into the bore so returned it. Bye would like a bigger handwheel anyway. Thx for input

can you recommend where to buy one?

To give you a frame of reference here...

 

The 206RB series is an upholstery machine. The stock handwheel/pulley on the machine combined with a standard pulley on a motor allow the machine enough penetrating force yet still have plenty of top-end speed to run through yards and yards of upholstery fabrics in a production environment.

For leather, different ballgame.

Nobody selling these machines is going to recommend throwing an iron reducer wheel in the mix and increasing the torque to a machine past what it was engineered for. It arguably can reduce the life expectancy of the machine if you are placing a greater amount of torque to it than was originally intended.

However, people do it all the time. These machines are made to last for years, sewing 40+ hours a week. They can handle a hobby level of abuse.

 

You have some choices:

Use the stock 550w motor with the smallest pulley you can fit on it (typically 45mm - 50mm) (cheap)

and/or

Add a larger pulley in place of the stock handwheel. You want one with a 3L belt profile (still cheap)

and/or

Add a speed reducer pulley under the table (about $150 - $200)

and/or

Add a high-end motor with good low speed control ($250 - $1000)

 

 

 

 

 

[R8R]

See this thread, pretty much this whole conversation is covered:

 

[dikman]

And if you want to take it to the next level -

large wheel + speed reducer, gives me 1 stitch every 2.5 secs! Yes, I know, it's a bit extreme, but........

Seriously, a 2" on the motor and a 6 - 8" on the head unit (as in R8R's link) should give you the control you want.

[wydfuqnopn]

man that is beautiful right there. every 2.5 seconds that's almost enough time to pour a cup of coffee..in the kitchen. guys I thank you. this forum is incredible. so glad I joined. wish I would have before I bought my machine but hey, whaddayado.

 

[dikman]

Don't run yourself down, you did pretty good on your purchase, they're a very good machine to start with and should be more than adequate for your current needs. Fit the smaller motor pulley (hopefully there should be enough adjustment to use the existing belt) and then experiment with the settings on the servo, who knows, it may be fine as it is.

[wydfuqnopn]

well I returned the pulley I bought bevause there wasn't a place to set it to the bore so then tonight I bought this one https://www.walmart.com/ip/Grizzly-G5436-Single-V-Groove-Pulley-6-Pitch-Dia-1-2-Bore/134318402 it has two places for the screws like the one that came with it and it is a little under two times the size. any bigger and I would have to move the bobbin winder around. (musnt do that) hahahahaahah. just gonna run with it. thanks again gentleman

[dikman]

That's the one that myjtp used in the link that R8R posted. Should work fine.

[Gregg From Keystone Sewing]

11 hours ago, dikman said:

And if you want to take it to the next level -

large wheel + speed reducer, gives me 1 stitch every 2.5 secs! Yes, I know, it's a bit extreme, but........

Seriously, a 2" on the motor and a 6 - 8" on the head unit (as in R8R's link) should give you the control you want.

Wow, now that's slower than slow.  I would fall asleep behind the needle with that setup.  Very nice, I'm sure it works great.  Like Dikman said, Consew 206RB series machines are great and one of our most popular machines that we offer.  We've been selling them since they came out in the 70's and never stopped.  

Edited November 6, 2018 by Gregg From Keystone Sewing

[dikman]

It's probably too slow to be practical, but it was done to compensate for the servo as I found the pedal transition from stop to max was too sudden for my liking.

[Gymnast]

I just noticed this topic, and I hope it is in order to revive this thread about slow speed control.

I have noticed some recent youtube videos showing the speed control of servo motors. And I was not impressed by the slow speed control. Then I found these two 7 years old threads here dealing with the same problem and making a simple modification to some of the motors.

https://leatherworker.net/forum/topic/41916-having-problems-with-servo-motor-speed-control/?tab=comments#comment-260742

https://leatherworker.net/forum/topic/41483-servo-motor-mod-diy-easier-speed-control/?tab=comments#comment-258131

Did the servo motors on market improve regarding slow speed control the past 7 years?

[dikman]

I think you'll find that they've changed the design of the motors since that was written and many of them no longer use the optical method of speed control.

[Gymnast]

13 hours ago, dikman said:

I think you'll find that they've changed the design of the motors since that was written and many of them no longer use the optical method of speed control.

Thanks for your reply

It seems like the old findings from 2012 is not referenced any more. The funny thing is about the case in 2012 was, that it was a new man in the busines that started sewing and was unhappy with the disign. Most others would just accept the servo motor and "that you just need to pratice" to get better - its is not the machine that has a problem.

I can confirm one called Yuma 550 watt, with another design shown here:

https://www.youtube.com/watch?v=w7sh972qqmk

It uses a magnet and a hall element magnetic field strength sensor. So the movement of the magnet changes the field at the hall sensor. However it cannot be a perfect system either. The earth magnetic field is about 50 micro Tesla, and it may somewhat disturb with the speed depending of the position in the World and direction of the table. However I do not know its performance regarding low speed.

What I see is, that the lowest possible speed of the machines seems to be quite high (in my opinion). I would not be satisfied unless you could reach below 30 stitches/min. But it seems to me, that the speed jumps up from zero speed to a quite high low level speed. I know something about Electronics and Electric motors, and a well designed servo motor should have no problem in operating with a factor 100 in speed from lowest speed to maximum speed. And you should be able to control that with a good pedal as well. So I cannot figure out why this is not done with servo motors for sewing machines.

This video from 2012 show this good low speed control with a modified servo motor: https://youtu.be/-h5U32SDZ38

I noticed these two recent videos from 2018 with quite high low speed of about 120 stitches/min. It is a Ho Hsing G60 servo motor on Pfaff 1245:

https://www.youtube.com/watch?v=oJVlq_L16ew

This other kind have the low speed limit of about 60 stitches/min with Sewpro 1100 NPFL:

https://www.youtube.com/watch?v=UT2CRg2HiYY

You have many more videos out there, they all seems to have this "to me strange" low speed limit. And many of them do only have a span of about a factor 5 from their controlable lowest speed to their max speed.

Perhaps I should make a new thread here asking about this.

[Gudmundur]

This is a interesting topic to me, because I just bought a servo motor from a polish company. The motor is Texi ac 750 SM with a synchronizer for up or down needle stop. I installed the motor on my old Singer 132K6, so far I understand the motor has a lower limit of 300 rounds pr. minute. And a upper limit of 3000. It took five days to reach my home address, with a weekend counted in. 

Best wishes

GK

[Wizcrafts]

I really detest the brushless servo motors that start at 100 or more rpm. They cause the machine to start and stop with a jerk. The last one I had (and replaced) was on a Techsew 2700 I bought second hand. When I first set it up, the motor caused such a mechanical jolt that the bobbin thread unloaded in the bobbin basket. I replaced it with a Family Sew FS-550s that starts at zero and smoothly increases in speed. That is the only way I go, other than regular clutch motors.

More slow speed torque is achieved by installing a speed reducer. My machine came with an unattached 2:1 reducer which is now installed. I can start sewing at a few rpm and ramp up to about 1800 with the reducer installed. It starts and stops without a jolt.

[Gudmundur]

My 132K6 came with a danish clutch motor that I had no way of controling the speed of. As I looked for a solution I came up with this servo motor. I had looked at speed reducers, but as the clutch motor has a rather large wheel I decidet for the servo motor. It did not disapoint me, it starts and stop rather smoothly. No jolting, I wrote before that it has lower limit of 300 rpm, that is not right (my bad) It is adjustable so that max speed can be 300 to 3000 rpm. From zero to what ever I decide. And as the wheel is just 65 mm it works well.

Now I have to work on the sewing machine as there are some things that need adjusting.

Best wishes

GK

[Wizcrafts]

1 hour ago, Gudmundur said:

My 132K6 came with a danish clutch motor that I had no way of controling the speed of.

Most clutch motors have a big bolt on the right end, in front of the output shaft, which can be adjusted for more or less free play. This free play works with a coil spring that causes the control arm to stay up until you push down on the floor pedal. Tighten up the coil spring to make sure the arm is all the way up in idle, then back off the adjustment bolt until you have enough slack/free motion to feather the clutch.

If the motor wants to go off to the races despite your adjustments, place a tennis ball under the toe end of the floor pedal. Then buy a smaller motor pulley that fits the shaft on the motor and a new v-belt to match the longer reach. If the motor is still grabby, open it up and smear a thin coat of light grease on the clutch pad to let it slip a bit. Unless you have restless leg syndrome, you should be able to learn to feather the clutch for slow speed operation. It's the same as driving a clutch car.

[Gudmundur]

Thank you very much for this information, unfortunately I already have given the old motor away, and mounted the servo motor. But I will most certainly remember this in the future.

As a matter of fact I have rls but that does not bother me when awake, and when sleeping the wife has forbidden me to operate the sewing machine  

Best wishes

GK

[Gymnast]

On ‎8‎/‎15‎/‎2019 at 1:35 PM, Gudmundur said:

This is a interesting topic to me, because I just bought a servo motor from a polish company. The motor is Texi ac 750 SM with a synchronizer for up or down needle stop. I installed the motor on my old Singer 132K6, so far I understand the motor has a lower limit of 300 rounds pr. minute. And a upper limit of 3000. It took five days to reach my home address, with a weekend counted in. 

Best wishes

GK

I hope, that the motor should be able to turn at lower speed than 300 RPM. It seems to be a high speed to me.

This link is to a dealer of what I think is your motor:

https://www.strima.com/texi-power-750-sm-ac-servo-motor-with-synchronizer/item/1047899 

Another guy, DanishMan is sometimes around this Leatherworkers forum. He uses another polish servo motor from Zoje, and recommend it: 

https://www.sewtex.de/Motore--Gestell--Tischplatte--Zubehoer-fuer-Naehmaschinen--Stuehle--Leuchten--Transportwagen--Industriestuhl--Schere/ZOJE-TZ-ZJ750W-S-Servomotor--Naehmaschinenmotor.htmlhttps://www.sewtex.de/Motore--Gestell--Tischplatte--Zubehoer-fuer-Naehmaschinen--Stuehle--Leuchten--Transportwagen--Industriestuhl--Schere/ZOJE-TZ-ZJ750W-S-Servomotor--Naehmaschinenmotor.html

When I compare the Pictures, they look the same, and I suspect they come from the same Chineese manufacturer. However important software can be different.

I found and read this link to some service information on a servo motor from Zoje:

http://files.zoje.com/uploads/doc/WR596 training.pdf

I guess, it is the same motor, but I am not sure. But this service information reveal a motor and control unit, that is designed for sewing machines. Its is a well designed motor drive and uses a brushless DC motor. It is not just a modified industrial multi purpose motor drive.

In order to control a motor like that at low speeds, you need a bit more complicated software in order to avoid too much ripple in torque. Furthermore you need to measure or estimate the temperature (by software) of the copper windings in the motor, because the blower on the motor shaft cooling the motor is not effective at low speeds.

I made this thread in this forum to show off my "home made" speed control of one of my sewing machines. I did that, because I suspect, that some leatherworkers speed control are not well designed, and they should see what is possible:

https://leatherworker.net/forum/topic/86489-do-you-like-this-speed-control/

[Gudmundur]

Hi Gymnast

Yes iI bought the motor from Strima, and I did not formulate myself right, about the speeds. The max speed can be adjusted from almozt zero up to 300 to 3000 rpm.

I am quit satisfied with the motor so far.

Best wishes

GK