Help With A Servo Motor

[Constabulary]

The speed reducer it self mostlikely is not the problem. The problem is the position of your SR. I have no problems with mine and I didn´t cut a wider or longer slot in my table. My SR is "home made" but pretty much the same "style". I only had to move the motor a bit to the back. So I would guess your setup is the problem and not the part.

[JoMama]

The speed reducer it self mostlikely is not the problem. The problem is the position of your SR. I have no problems with mine and I didn´t cut a wider or longer slot in my table. My SR is "home made" but pretty much the same "style". I only had to move the motor a bit to the back. So I would guess your setup is the problem and not the part.

You guessed wrong.

The problem is that the speed reducer I bought does not attach easily, when there is not enough table to move the motor back or forward. I had to make a couple spacers and move the motor down 5". If I had more table I could have moved it back 4".

The speed reducer I now wish I had bought will fit any table, appears to bolt right up with no drilling needed and a lot less fidgeting with alignment, not to mention it uses sealed ball bearings instead of cheap bushings and keeps the motor over the pedal so your linkage is not at some goofy angle.

[Tramps Leatherworking]

Well, if the OP isn't totally confused by now i'm amazed...

Just get yourself a decent servo (shop around for the best deal) buy a ball bearing SR, I have this one http://www.ebay.com/itm/NEW-Nick-O-Sew-NKS-SR2-3-6-9-Dual-Speed-Reducer/151545749209?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D28797%26meid%3Dbc151193770f4cb9b367fb8ec318f8f2%26pid%3D100033%26rk%3D2%26rkt%3D3%26sd%3D381157749794 mount them on your table, and enjoy...

[SARK9]

I've done several clutch motor/servo swaps and with the typical narrow industrial tables, my solution has been to install an offset plate that mounts to the original carriage bolts in your table, but offsets some new mounting studs to the right side to compensate for the extra width of the reducer pulley. This arrangement also lets the motor set back far enough that the large pulley won't interfere with the motor pulley, and allows normal use of the belt cutout and the tilt-back of the machine head.

-DC

Edited February 28, 2015 by SARK9

[Constabulary]

@JoMama

You are right, I forgot that my table is deeper than most others. So I was a bit on the wrong track!

The idea of SARK9 is good. I think you also can do that with plywood and carriage bolts for the motor. Or use drive in nuts or threaded inserts instead.

[SARK9]

Ugh. I just noticed that the program hadn't saved the last dimensions I added when I attached that file of the plate measurements. Here's the finished print.

This is a picture of the whole assembly on a Singer 20U33 I just got for doing some wide zigzags. Notice I have the speed reducer belt disconnected, as the latest motor I bought *seems* to not need any help at all with the speed control whatsoever. They either corrected the shape of the optical controller blade or I got a one in a million copy. I have replaced the stock 90mm pulley with a 50mm motor pulley I made. The max RPM is set at 4500 and delay is zero, but its easily able to do one stitch a lifetime if I want.

-DC

Edited February 28, 2015 by SARK9

[JoMama]

Moving the motor towards the rear of the table does not let you use the belt tension adjustment feature on the motor. Moving it below the pulley preserves that functionality.

I'm a mechanical engineer and have a full CNC machine shop for my real work and if I had to do it again, I'd gladly spend the extra 30% for the bolt on reducer that drops the motor below the pulley. Some things are just not worth wasting time on.

[SARK9]

>>Moving the motor towards the rear of the table does not let you use the belt tension adjustment feature on the motor.<<

Moving the motor towards the rear allows you to mount **your speed reducer's small pulley** in a location back behind the hinge point of the machine head, allowing normal tilting, as has been stated several times. The "tension adjustment" (?) works perfectly normally, it remains a simple function of the correct belt length as is usually the case. Selecting the length of the short belt (running from the motor to the reducer's large pulley) does become less forgiving, as the motor is adjusting away in a reduced arc, but its not difficult to work out. Frequently, the 3L420 belt that comes with a stock clutch motor seems to be just right for a servo with a 50mm pulley when the speed reducer is mounted towards the rear as shown.

-DC

Edited March 3, 2015 by SARK9

[Ole South]

Just curious: does the "drop motor" SR act as a resonator increasing motor noise by any factor?

I've always wondered about that, probably more of a factor with a clutch motor than a servo but still...?

Edited March 3, 2015 by Ole South

[Wizcrafts]

Just curious: does the "drop motor" SR act as a resonator increasing motor noise by any factor?

I've always wondered about that, probably more of a factor with a clutch motor than a servo but still...?

The motor only turns when you apply pedal to it. The combined sound of the servo motor and speed reducer is nowhere near the level of sound of a typical clutch motor that spins all the time. I don't even notice the reducer, aside from the power boost it gives.