How To Slow It Down...

[SARK9]

The Parable of the Clutch Motor:

You'll probably never see steam tractor buffs recommending their personal darlings to an aspiring youngster who actually wants to take up farming.

 

-DC

 

[TinkerTailor]

2 hours ago, MADMAX22 said:

In my experience my 211G155 clutch motor was great for wide open and was very touchy for slower operations, the punching power was ok for very thin stuff. By just changing to a adjustable speed servo motor the control at slower speeds was greatly increased. The slow speed punching power is now adequate and it will still fly right along for the longer runs, just as fast as the clutch motor that was on it previously.

I had to do a couple of MC seats on the 4500 due to the 211 being out of commission and it was a test of patience as far as time was concerned. Not that I am a speed demon by any means. Not to mention getting a free hand straight run of stitches is actually more difficult at really slow speeds. It takes a little bit of speed to get those straight runs to come out right and obviously the more experienced you are the faster they can be accomplished. I am still at the slower end of that.  

This. I have had my 441 clone set up on both the middle pulley and the slow one. On the middle, it would slow down but the motor was notchy seeming to change speeds in steps and it lacked torque at low speed. The motor was not happy.  On the slow pulley, due to the increased motor rpm, I can get smoother, more powerful slow speed, and still get more than enough speed to getter done with an edge guide. I turned up the motor to max on the slow pulley and got it fast enough smell burning leather from the hot needle in 8oz of veg. Now i leave set up for stitch by stitch all the way up to 3-4 stitches a second. On a small detailed project, or one that is really thick and dense, I will just turn the motor down a few notches to limit my top speed just in case the cat steps on the pedal while I am sewing. It actually happened.  I was sewing 3/4 inch of dry veg tan for these "brick of leather" keychains i sometimes make, and the cat stepped on the pedal while it was set for really high speed. Needle did not like the mach 9 through concrete sewing and exploded into shards flying at me. That reminds me, were safety glasses with these machines....

Go slow at the machine and speed up all of the other operations first. You probably wasted more time walking back and forth in the shop to get stuff while making a project than you will ever save sewing faster.  The sewing time on a project, even slowly, is a small part of it.

Working as a contract sewer and basically getting paid by the stitch is not what most on here use their machines for and is a different story. That story will be available as a pdf on this site in 2017, and will be titled "Life of a Seamster, The Wizcraft Autobiography"..

[oldfarmboy]

On ‎9‎/‎10‎/‎2016 at 9:33 AM, northmount said:

Servo motors are variable speed control.  No clutch.  You can also slow your machine down by installing a pulley speed reducer set and by decreasing the size of your motor pulley, or increasing the size of your machine pulley.  Sewing leather with a hard temper and / or a thick stack of leather requires a lot of torque,  So even with a servo motor, you may still need to use a pulley speed reducer set.  Torque in general varies inversely with motor speed.  You can do a search here and find lots of threads and posts about servo motors.

Tom

I stopped by a local store that has a Reliable 3200SN on display. Didn't talk to sales as everyone was too busy but it was powered up with a piece of material on the bed so I tested it. Only checked at slow speed and it gave nice control. There must be some sort of control inside the end of the servo. Do all servos have that already built in or is this a specially built unit?

BTW, I just acquired a Singer 307G2 and it's control is far superior to the Pfaff. Not near as frightening to run. Even had the clutch assembly off the Pfaff to inspect. It did have some sort of old grease on the disc. Cleaned it all off as best as I could using acetone and sandpapered the metal disc. Hard to tell if there was any improvement. Looking like a speed reduction system is an upcoming project

[mikesc]

Quote

Do all servos have that already built in or is this a specially built unit?

What is in the inside depends on the manufacturer, some are controlled by a photocell ( there are some threads here on "how to mod" those, so that they have a less steep "initial bite" ) some are controlled entirely from the seperate "box" , some have a gearing system inside ( wiz has posted about those, one of the dealers here sells them )..I run a speed reducer ( that  I built, a 5:1 ) on a 211U166A , at the slowest speed that gives around one stitch every 5 seconds, allows one to "draw" using stitches in leather with it..love that control

Edited September 14, 2016 by mikesc

[Yetibelle]

The Servo motors have power settings - slow to fast 300-5000 stitch per inch just turn it up or down from the motor. 

[mikesc]

Some go slower ..I have a "jack" ( same type as constabulary, and I think maybe LumpenDoodle2 ..goes down to somewhere between 100 and 200 and up to 4500, speed is changed via separate control box with digital display ( can do changes in increments of 100 at a time )..but I don't know if the US dealers sell those..

I suspect that a geared model is probably better and stronger anyway, but have not seen any on sale separately in Europe.

Edited September 14, 2016 by mikesc

[dikman]

I don't think those internally geared models are available anymore? (Probably too expensive to make compared to a DC servo motor). My servos, from China, basically have two settings that I can adjust using the digital display - one sets the max speed and one sets the startup speed (I think, haven't got the book handy). Both settings affect each other to some extent, but between them and the speed reducers that I've fitted I can get the machines to run as slow, or fast, as I want.

Probably the same basic type as yours, Mike.

[Northmount]

From other posts on clutches, the cork needs some grease lube to be able to slip smoothly.

Tom

[laether]

found this thread. Bought old Pfaff 145 with this motor. I have a bit of a problem with speed. It needs quite a push and then runs way too fast if I dont immediately loose my foot. After that I can sew quite slowly but starting is the problem. Wonder if I can do anything about it?

Heres few pics, please advice me: what motor I have and what's that grey tube for? THANKS!!

[Constabulary]

The tube is a capacitor for running this motor on 220V instead of 380V. 2800 RPM is way to fast. Even if you slow it down with just a speed reducer (a pulley system) it´s still to fast for leather working. If you had a 1400 RPM motor you could slow it down with a smaller motor pulley and speed reducer but IMHO a 2800 rpm motor is not worth it. I would replace the motor with a servo motor + speed reducer.

Or - if you really want to keep this old motor you probbaly can slow it down with a frequency converter but I personally would go with a servo motor + speed reducer. I cannot explain the FQ thingy but someone else will jump in here and let you know.

[brmax]

We initally should ask or address your mention of “ it needs quite a push”.

So I think I might understand one reason but more importantly the picture leads me to this question: When does the motor need this push? Is it when the power is turned on or well after and any time later when you want to hit the sew/go pedal. 

 

Good day

Floyd

[laether]

Thank you @Constabulary and @brmax!

3 hours ago, brmax said:

We initally should ask or address your mention of “ it needs quite a push”.

So I think I might understand one reason but more importantly the picture leads me to this question: When does the motor need this push? Is it when the power is turned on or well after and any time later when you want to hit the sew/go pedal. 

 

Good day

Floyd

I try to explain what I meant:

It feels I have to hit/push the pedal quite hard to get the machine going, but after that I can loose my foot so it goes slower and is almost manageable. And at this slower speed I'm pretty certain I push the pedal less than I did when trying to get the machine going.

But one very important thing I just noticed: At the back of the machine, there's this "wing nut" which is for adjusting the foot height. When its like in the picture (lowest) the machine starts easier, meaning I push the pedal carefully and it starts sewing quite nicely. This is how it was when I bought the machine. Now yesterday I began learning the machine by adjusting certain things (foot height & pressure) and when I adjusted the wing nut so that the foot is "highest" the trouble started. Trouble being the exact thing: I have to push the pedal quite hard to get the machine going and if I don't immediately loose my foot, it goes way way too fast.

[Northmount]

You are probably trying to push the presser foot through the plate or feed dogs.  I would suggest that instead of randomly trying these adjustments, you obtain the service/instruction manual and go through the complete setup, starting witht he outlined sequence.  It must be making more noise as it runs as well instead of a nice smooth operation.

Tom

[Uwe]

There's also simple spring and lever physics at work. The longer the lever, the less force it takes to move something. The more you deflect a spring, the more force it takes. In the bottom position of that wing nut, you have a long lever and short spring deflection, resulting in relatively low force/torque required to move things. In the uppermost position, you have half the lever and twice the spring deflection. So it may take four times the force (torque) to walk the feet in the upper wing nut position. Once things start moving, the momentum of all the rotating masses help provide torque.

Edited May 2, 2018 by Uwe

[dikman]

The motor is a "capacitor start" type, hence the capacitor (silver tube) which is used to give a phase shift to get the motor started. It's possible that the capacitor has dried out a bit (happens as they age) and may affect the starting of the motor. Modern motors usually have the cap. built in, not mounted outside.

I agree with replacing the motor, as it's obviously pretty old and may start giving other problems. A servo is really the best mod you can do to a walking foot machine.

[brmax]

Thanks for the reply, it helped steer me away from thinking any capacitor issues. 

I have to mention an investment in a Servo motor will be a good choice. It will help a serious amount in a slower machine speed.  If an extreme reduction is needed the use of a pulley speed reducer is warranted. These can be purchased and or built, there are some very new styles. These new styles have some benefits, in either case the reducers do have a steep cost. 

A point to think about is the factory handwheel pulley, most are very small diameter. This as you know is for speed, as garmet sewing is all about putting out the products, a lot!

 

Good day

Floyd

[laether]

13 hours ago, Uwe said:

There's also simple spring and lever physics at work. The longer the lever, the less force it takes to move something. The more you deflect a spring, the more force it takes. In the bottom position of that wing nut, you have a long lever and short spring deflection, resulting in relatively low force/torque required to move things. In the uppermost position, you have half the lever and twice the spring deflection. So it may take four times the force (torque) to walk the feet in the upper wing nut position. Once things start moving, the momentum of all the rotating masses help provide torque.

Thank you @Uwe again! This is just the kinda physics I was thinking is involved here, well put! =)

Thanks to others aswell. I'm going to invest on new servo motor.

Is there a thread about servos? I found this, but its quite short:
http://leatherworker.net/forum/topic/80458-servo-motor/

I would appreciate if you could advise me a bit on them? What kind of servo do I need? Here's the specs:

-I'm in EU
-do not want cheapest chinese one, would prefer buying from Germany etc.
-but also wouldnt need the most expensive either...I guess something in the middle...
-will take the motor & my machine to a maintenance shop, just would prefer buying the motor myself, to save some €s

 

Edited May 2, 2018 by laether

[Northmount]

@laether Lots of post about servos.  Try a google search "site:leatherworker.net servo" without the quotes.  Add additional words to refine your search.

Tom

[laether]

10 hours ago, Northmount said:

@laether Lots of post about servos.  Try a google search "site:leatherworker.net servo" without the quotes.  Add additional words to refine your search.

Tom

yes, thanks!

[Uwe]

Efka in Germany (http://efka.net) makes really good servo motor and controller systems. They may not qualify for "in the middle" status. 

[laether]

1 hour ago, Uwe said:

Efka in Germany (http://efka.net) makes really good servo motor and controller systems. They may not qualify for "in the middle" status. 

thanks, already found them...and yes, a bit over my budget...

[brmax]

What other company’s are in your locations.

Just thinking here and curious if somethings in the U.K. Especially within a 250.euro range and is obtainable with reasonable shipping or freight charges.

 

Good day

Floyd

[JessH]

On 9/3/2014 at 2:35 PM, CowboyBob said:

I've always just used wheel bearing grease or Vaseline on the clutch pad(about a teaspoon)just smear it around.As a quick fix machine oil on the pad will work.They grab because they dry out so any lube helps it to slip & doesn't hurt it at all.

This comment gives me real hope of more low speed control? I've already put the smallest direct reducer wheel on, (can't get the tri-pulley in the UK I would love to have) so the top speed no longer scares me to death. It's the first machine in my life I've ever been scared of, I had no idea a sewing machine could go that fast!. Sometimes I can control the lower speed, other times no way, though I'm sure my feet are doing the same thing. As someone suggested above, my belt is on the point of slipping, though I didn't do this on purpose, and had been wondering if that was part of the problem? This grabbing of dry clutch would make perfect sense, as I really feel the machine 'grabs' suddenly and accelerates like a Ferrari on a rally. Now just have to work out how to get the grease/oil onto the clutch? Any suggestions as to how to do that for a non engineer but practical person very gratefully received?

[CowboyBob]

Can you post a pic of the pulley side of your motor?

Edited August 25, 2018 by CowboyBob

[chrisash]

Don't forget that most high speed machines need the high speed to work the automatic oiling