servo motor grumble

[BillyR]

I have a brand new machine with servo motor and speed reducer.At the lowest speeds it grumbles and vibrates and as speed increases it smooths out.. it sews just fine but the low speed grumble is annoying.its mounted on a standard metal frame table which also picks up the vibration....thats around a stitch a second..Is that normal for these motors? Oddly if I quickly let up on the pedal and quickly press down it becomes silent at all speeds.   any thoughts?

[Wizcrafts]

Check all of the screws, nuts on bolts under the table to ensure that they are as tight as possible. This includes the screws or bolts for the reducer. Also, check the horizontal plane alignment of the belts. The motor pulley should line up with the large reducer pulley. The small reducer pulley should line up with the machine pulley. Youi may need to reposition the motor, reducer, and/or machine to get all three inline. Finally, watch the motion of the belts while the machine is in slow motion. Some belts are twisted, or welded off center from the factory and may give a rough ride at some speeds. Replacing those belts often smooths out the action at all speeds.

[brmax]

You may have done this already. But if you can eliminate the machine belt, so to check the other drives. This may isolate an issue easier.  

Also it seems this aproach also works for listening or feeling the machine issues. This can be a great method in troubleshooting. Good luck and keep us posted

 

Floyd

[kgg]

Hi BillyR,

This could be as simple as your table not being level in one corner or the servo motor needing to be broke in so what I would try first is try an locate to source of the problem. I would remove the belts from the servo motor to the speed reducer and the speed reducer belt to the sewing machine pulley and run it for five minutes at various speed settings.

Then I would run it at the low speed and see if your grumbling and vibration are present. If there is a grumbling and vibration then the problem has to due with the servo motor or its mounting bolts. 

If there is no grumbling or vibration present connect the servo belt to the speed reducer. If there is a grumbling and vibration then the problem has to due with the speed reducer, its mounting bolts, pulley to pulley alignment, belt tension and/or dry / damaged bearing.

If there is no grumbling or vibration present connect the speed reducer to the sewing machine. If there is grumbling or vibration present it could be an off balance reducer pulley, pulley to pulley alignment issue or a belt tension / belt size issue. I would also check and see if the sewing machine is seated properly in its mounting slot and if there are anti vibration dampers needed they are present as well as the table top is true.

If there is no grumbling or vibration present sew to your hearts content.

My two cents worth,

kgg

[dikman]

My guess, assuming nothing's loose, is a belt problem (maybe too loose?). I had a similar issue once and all I had to do was tighten the belt.

[CowboyBob]

10 hours ago, Wizcrafts said:

Check all of the screws, nuts on bolts under the table to ensure that they are as tight as possible. This includes the screws or bolts for the reducer. Also, check the horizontal plane alignment of the belts. The motor pulley should line up with the large reducer pulley. The small reducer pulley should line up with the machine pulley. Youi may need to reposition the motor, reducer, and/or machine to get all three inline. Finally, watch the motion of the belts while the machine is in slow motion. Some belts are twisted, or welded off center from the factory and may give a rough ride at some speeds. Replacing those belts often smooths out the action at all speeds.

@Wiz,didn't some of the servos I sold you yrs ago with the digital readout do that?

[brmax]

A video would possibly be a great help. I am trying now this morning to reconsider the mention: accelerate to the problem, yet if let off and re-accelerate quickly this issue disappears. 

Good day

Floyd

[BillyR]

yes..thats the weird thing. I don't know how servos work but no vibration when I do that maneuver..it runs noisely and smooth. Its as if once the motor gains momemtum and you quickly reengage it it either mechanically or electronically changes itself. You can only hear the machine working, not the motor..Isn't that the way they should be?  It's the second motor since I thought the first defective so the motor isn't defective, maybe the design is..

[Wizcrafts]

4 hours ago, CowboyBob said:

@Wiz,didn't some of the servos I sold you yrs ago with the digital readout do that?

That turned out to be caused by warped or misaligned v-belts. You sent new belts that laid flat and that fixed the vibration.

[CowboyBob]

Ok,we had some that chattered @ low speed something like the OP.

[Wizcrafts]

8 minutes ago, CowboyBob said:

Ok,we had some that chattered @ low speed something like the OP.

I did get one push button servo from you in 2011 that had a cutout at a certain point of movement of the pedal. It eventually died altogether. The Family Sew servo motors you now sell are so much better and easier to control. The Sew Pro was also a very good servo motor while it was in production. Too bad they folded.

[BillyR]

thanks for all the input..

If I could take a quick poll

is your servo motor..at the lowest speed

a- noisless..only hear the machine

b-hums along at a constant backround noise level

c makes more noise at low speeds

just trying to get a take on what to expect..on all the videos all you hear are the machine clacking, not the motors

[RockyAussie]

c. Mine is a Cowboy though and the reducer is all in a metal box frame so it behaves a bit like a bell. High foot pressure makes it more noticeable.

[BillyR]

 

turns out that the motor is not the problem, just the way I operate it, so I replaced it with a simpler motor more to my liking. Thanks for all the help folks

 

[dikman]

Good that you found the problem (operator error?) but I must admit I'm a bit confused by what you mean by a "simpler motor".