How To Slow It Down...

[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.