Looking for a low speed start servo

[Constabulary]

I run 2 Jack Servos with 750w. One on a 111G156 with 1:3 speed reducer. No problems since 2014. The 111G155 / 156 machines have safety clutches if something goes wrong but generally you cannot overpower these machines. The safety clutch will not release just because of a higher power motor you need a resistance like needle hitting a hard spot in the material or the needle plate or at the hooks thread has accumulated a bird nest and blocks it but other than that you motor will run without problems. I sew really hard cotton webbing. BTW - I never have released my safety clutch.  At slow speed you rather hear the motor knurling when sewing hard material but again the safety clutch never released. Thats at least my experience.

[Wizcrafts]

5 hours ago, Constabulary said:

Look at that - so I better shut up 

But 0 is off, right? And next step is 350 or is there an acceleration ramp between 0 and 350 when the knob is on 0?

If that Eagle brand motor works like my Family Sew motor, the speed settings around the dial are the maximum motor speed, not the minimum. these motors start at zero and increase linearly as you depress the pedal. there is no ramping up to speed. There may or may not be enough turnover power at the slowest setting until one gives it about half pedal. But, mine all have a 50mm pulley and can keep a machine spinning a stitch or two per second. I am satisfied with my Family Sew motors.

Regarding servos feeding reducers, that's the cat's meow. My Cowboy CB4500 is geared down 9:1 from the motor to the reducer to the hand wheel. I can sew at a minimum speed of watching grass grow.

[Gymnast]

9 hours ago, Constabulary said:

Look at that - so I better shut up 

But 0 is off, right? And next step is 350 or is there an acceleration ramp between 0 and 350 when the knob is on 0?

I agree with Wiz. For the brushed DC motor type, the motor is controlled from zero. However the drive types with a brushed DC-motor do not have a steep moment curve as a brushless motor with more drive electronics. If you run a brushed DC motor drive for sewing machines very slow, and it gets some high torque load, the motor can be stopped. A brushless motor drive running slow will resist being stopped with all its torque available. In this way these servo motors are different and some may like one more than the other. And they may each be better for different jobs. This video show how this response to torque works on the two motor types: https://youtu.be/SOyQtt3eDLw

The Jack servo motors are of the brushless type. I tried to look for their specification regarding lowest constant speed, but I could not find it.

[chrisash]

On 11/8/2020 at 12:50 PM, Constabulary said:

I run 2 Jack Servos with 750w. One on a 111G156 with 1:3 speed reducer. No problems since 2014. The 111G155 / 156 machines have safety clutches if something goes wrong but generally you cannot overpower these machines. The safety clutch will not release just because of a higher power motor you need a resistance like needle hitting a hard spot in the material or the needle plate or at the hooks thread has accumulated a bird nest and blocks it but other than that you motor will run without problems. I sew really hard cotton webbing. BTW - I never have released my safety clutch.  At slow speed you rather hear the motor knurling when sewing hard material but again the safety clutch never released. Thats at least my experience.

Hi

Have you run the 750 watt jk563a at the quoted 200 rpm and does it have power  at that speed to sew 4 mm leather

Have just measured the hand wheel at 80 mm diameter and the intended drive pulley at 45 mm

Edited November 16, 2020 by chrisash