Servo motor from Dürkopp Adler with very low speed.

[Gymnast]

Slow speed and slow speed control of sewing machines have quite often been discussed in this forum. Many leatherworkers like to have the possibility of very slow speed control.

I just read some specifications for a Dürkopp Adler brushless servo motor, and it is possible to set the lowest speed to be 10 RPM. Most brushless servo motors I have studied got a minimum speed of 100 RPM and perhaps more.

I think Dürkopp Adler uses motors from EFKA, but I am not sure. On the EFKA home page I do not find specifications on that low speed yet. For a specific Dürkopp-Adler machine, they reference EFKA DC1550 DA321G drive at https://www.efka.net/en/

You find a parameter of minimum speed to be set down to 10 RPM according to page 15 in this parameters manual:
https://www.duerkopp-adler.com/commons/download/public/525i/0791_523901.pdf

The default setting is 150 RPM.

Do you have any experience in using this kind of servomotor down to this very low speed of 10 RPM?

[dikman]

I wonder what the torque would be like at that speed? I've found speed reducers are the best way to get very slow speed with a servo as this also gives increased torque.

[Constabulary]

EFKA Servos are high end and super high priced motors that can control a lot of bells and whistles which "most" folks do not need for plain sewing. They are for sure top quality motors - no doubt but they cost a grand ++ easily and are far beyond what I would pay. I agree with dikman a "plain" servo + small 40-50mm pulley + 1:3 speed reducer is a super solution for most applications and affordable as well.

College sewing has some data + prices for the EFKAS:

https://www.college-sewing.co.uk/ab321-dc1550-efka-servo-motor.html

https://www.college-sewing.co.uk/ab321-dc1550-efka-servo-motor.html

Edited October 19, 2021 by Constabulary

[Cumberland Highpower]

I'm a little struck at the complete lack of options for machines here in the US.   Virtually nothing on the market other than Chinese/Taiwanese clutch motors and cheap servos that seem to be poorly made/designed.    Most everyone with a heavier machine uses a speed reducer pulley system.

I guess I understand the economy mindset, I have it to a degree.   

It would be nice to find something better as an option.   Efka setups are very expensive and hard to find here in the US as new items.

After some searching in the recent past, it appears there are Japanese made servos out there.  Mitusbishi has a  couple that if I remember right were labeled "G5" and were between 500-700 USD. I'd think they would have to be much superior to the inferior Chinese servos?

Edited October 19, 2021 by Cumberland Highpower

[Constabulary]

Hoshing servos are another option for "better servos". Not sure what kind of brand RELIABLE is but they at least look quite good but don´t know how well they perform.

https://reliablecorporation.com/collections/motors

I´m using JACK servos and I´m quite please but they are not high end either but they work well for me. And JACK is a known manufacturer of a wide range of sewing machines (at least). I would buy one again.

[Gymnast]

Thanks for the replies. I agree, that most leatherworkers would look for a solution with a speed reducer. But perhaps a few would like the extra range of speed (from minimum to max speed) that a machine could get with such a motor, because it could add some more flexibility for some machines. But I should like to know, if someone have tried to use the motor with such low speed and how it actually perform. The price level is indeed very high for these Efka motors. However you may find one second hand on a machine.

If you got a machine on factory floor for mass production, I guess you look for many bells and whistles to increase production rate and then the high price can be justified.

I tried to look for a specification for minimum speed for the Reliable brand, but could not find it.

 

[chrisash]

Another vote for Jack servo's

[kgg]

On 10/18/2021 at 12:01 PM, Gymnast said:

I just read some specifications for a Dürkopp Adler brushless servo motor, and it is possible to set the lowest speed to be 10 RPM.

That is a amazing slow speed but for the average joe the cost of the motor I think would be out of reach and to complicated for most hobbyists. I use the old fashion plain jane "brush" motors on all of my machines easy to repair and cost effective. I also don't have speed reducers installed on any of my machines. My attitude is two fold:

I follow "KISS"  so no computer /electronic stuff to screw up as I have enough user errors to contend with as it is, "me".

If I have to use a speed reducer to get added torque to gain punching power I am using the wrong machine.

5 hours ago, Gymnast said:

I tried to look for a specification for minimum speed for the Reliable brand, but could not find it.

The Sairite Workhorse servo manual may help ( www.manualslib.com/manual/1644613/Sailrite-Fabricator.html ) as it is a copy of the Reliable servo motor.

kgg

 

[Cumberland Highpower]

Other than maybe limited market ( Leatherworkers are mostly hobbyists I guess),   Seems like someone would offer a clutch motor or a servo with a 4:1 gear box bolted to the face.

That would be an easy solution and could be make to be drop in to a standard clutch motor.   

I have 3 machines with GE Gear Reduction motors on them, so obviously it's done with standard motors anyway....

[Gymnast]

11 hours ago, Cumberland Highpower said:

Other than maybe limited market ( Leatherworkers are mostly hobbyists I guess),   Seems like someone would offer a clutch motor or a servo with a 4:1 gear box bolted to the face.

That would be an easy solution and could be make to be drop in to a standard clutch motor.   

I have 3 machines with GE Gear Reduction motors on them, so obviously it's done with standard motors anyway....

I agree that a solution like that would be good. I think the problem is, that the market for slow speed servo motors for sewing machines is too small and may have too many variations in shaft diameters and so. A lot of gear motors for industrial use is mass produced and I am sure the cost is quite low this way. Small reduction gears are also used in tools like drills, circular saws etc. But if you can find a mass produced gear for some other purpose, that may fit, I guess you could get them quite cheap.

[falseyellow]

It is recommended that you use Mitusbishi or hohsing, which is more cost-effective, the minimum speed can be set to 50 rpm, and the heavy-duty machine chooses 750w. At present, I have not seen a motor for sewing machines on the market that is directly set to 10 rpm, because it is meaningless. The efkaDA321 can be set to a minimum speed of 40 rpm, and the AB321 can be set to 70 rpm.

[Garyak]

On 10/19/2021 at 6:01 AM, Constabulary said:

Hoshing servos are another option for "better servos". Not sure what kind of brand RELIABLE is but they at least look quite good but don´t know how well they perform.

https://reliablecorporation.com/collections/motors

I´m using JACK servos and I´m quite please but they are not high end either but they work well for me. And JACK is a known manufacturer of a wide range of sewing machines (at least). I would buy one again.

I just received a new reliable servo for my 145w204. I have servos from Reliable,Techsew, Cobra, Consew, and a gang of enduro pros that I chose a 110v plug for. All work as expected, except the Reliable. The Reliable at 225$ is by far the better motor. It meshed with my 145w like it was meant to be. It has the crawl stitch if you need to sleep between stitches, and more than enough power