Servo Motor Thunky Two-Step

[friquant]

Using the Consew C1000 servo motor with needle position sensor from this website: https://www.amazon.com/dp/B01N6IYMCZ

Also running this 45mm motor pulley: https://www.amazon.com/dp/B06ZZ42TGY

It is quite convenient that it can do single stitches (the majority of the time). The majority of the time it does give exactly one stitch, and it completes the stitch at its slowest possible speed, which with the gear reduction is about 110 stitches per minute.

But about 10 percent of the time, when I tap the gas pedal to ask for a single stitch, it instead does the following:

1. Goes one full revolution at HIGH speed, then
2. Makes a big THUNK sound, then
3. Goes one more full revolution at its minimum speed

Anybody else having issues like this? Here's a video. In this video, you can see a wave in the belt when the thunk happens. (Perhaps the thunk is a brake??)

 

Here is a video:

 

Edited February 20 by friquant
Clearer words

[kgg]

10 hours ago, friquant said:

Using the Consew C1000 servo motor with needle position sensor from this website

Are you using a speed reducer between the servo motor and the needle positioner? I would first replace the belt.

kgg

 

[friquant]

7 hours ago, kgg said:

Are you using a speed reducer between the servo motor and the needle positioner? I would first replace the belt.

kgg

 

I have considered replacing the belt, but it still functions smoothly and it is old enough to no longer have a chemical smell, so I think I'll keep it for now.

There is only one belt...from the 45mm motor pulley to the 80mm balance wheel pulley. (No other speed reducer.)

[AlZilla]

Assuming that the start position is the same every time you ask for a single stitch, it seems to me that the problem has to be a bad controller. 

If it starts in the same position every time and your foot tap is exactly that same every time, then it should do exactly the same thing every time.

I wouldn't think the position sensor would have anything to do with the speed.

Maybe a loose wire causing an inconsistent signal ... ?

[friquant]

Amazon sent me a replacement, and both units exhibit the same behavior. Still troubleshooting.

Edited Monday at 03:00 AM by friquant