How To Slow It Down...

[Constabulary]

Morning Trox - seems you are an early bird too

@ Joe

I´d personally go with a new servo too. You can buy a smaller pulley and new clutch discs but you may find out that the motor is still too fast and you already have one of the "slower" types with 1725rpm.

I have used several different clutch motors and the worst to control was a Singer from the 1980´s. It is still floating around here - that was a beast with 2800rpm and an almost uncontrollable clutch. The best clutch motor I had was a Pfaff (made by WEG Germany) but nothing beats my current servo.

I have had 2 servos before I got my current one (which I really like). One arrived broke (well that can happen) and the other one had a poor needle positioning system and made an annoying "beeeeeeeeep" sound. The one I´m using is a JACK JK-563A1 with NPS but I figured I do not need a needles positioning system as I´m sewing rather slow so I can see where and when the needle will stop. But I don´t think the JACK motors are not available in the US.

I think the FESM-550 seems to be a good one - Wizcraft often recommends it in some of his post.

I remember there was one with a gear reduction (suffix GR) and I think It came from Toledo Sewing Machine Co. But I don´t know if it is still available.

I´d contact them for further details.

[Trox]

Good morning to you Constabulary, Joe's motor is from the 1880`ties not 1980 ties. No, but its a pre WW2 motor I think. Anyway, I have the same one in grey color too and thats even worse than the earlier black color one. I agree about the WEG motor, I had one of those too. I also have a good one from Kobold Germany, only 370 Watt single Ph but good control on it. It came with my Pfaff machine and really did not needed to be changed out. I had that Cobra servo laying around and some speed reducers so I changed it out. I often wondered about that Jack motor with position system, was it any good? did the needle position work on it?

Yes Wiz talked allot about that gear reduction motor, but suddenly I heard nothing more about them. Perhaps it turned out to have low quality gears in it?? I do not know. Anyway, it was not available in 220V. Europe have a "pretty strict" quality control on electrical products "CE", perhaps thats why many of the Chinese motors do not turn up here.

That FESM 550 look pretty low tech and simple, just what the Chinese electronics production is capable to manage today. Then again the pot meter on them was not a good quality, according to the topics about them. Thats not a big problem anyway.

Tor

[Constabulary]

@ Jack - sorry for "occupying" your thread

Trox, seems the Jack actually has a problem with the NPS at very slow speed. High speed worked. But with the speed reducer installed it seems that the synchronizer has some problems. I reported it to College Sewing and a new (improved?) synchronizer is on the way already. But I figured I don´t really need a NPS at slow speed because you really can see where your needles will stop so from my point of view the NPS makes sense for high speed sewing but for slow sewing it doesn´t make a difference if I have one or not. But I still would recommend this motor and I will buy one again but w/o the NPS as I don´t really need it.

I will update my review of the motor when the new synchronizer has arrived.

I think it always depends on your personal "sewing situation" whether a motor suits for one or not. I have tried a few and this is the first I`m really please with but have to admit it is the first I´m using with a speed reducer and it makes a big difference.

BTW - this was my 2nd Servo

www.ebay.de/itm/251326331365

and the NPS did not position the needle properly, it always made 1 or 2 stitches too much.

And it had this annoying "beeeeeeeep" sound + it made an different sound when it was positioning the needle. Seller said this will end after 30Hrs but it didn´t. Next problem was you can´t turn off the NPS. And buying the same motor w/o NPS was not an option because of the stupid sound.

So this and not having the money for an EFKA lead me to the Jack motor which even has much more power and I like it!

Edited July 13, 2014 by Constabulary

[needles]

Hi Joe

i put a 40mm pulley on the motor at first which really slowed things down, and of course when using a light right foot, but the real difference cam when i swapped my clutch motor with a machine engineer and a small amount of cash for one of his new serrvo units, works a treat now....

good luck, i prayed daily that i would finish the working day with all my digits intact before the servo arrived....

Al

[Trox]

Hi Constabulary, Well the NPS will not work properly with a speed reducer because of the extra gear and its belt slippage. Some digital servos have the synchronizer that only calculate belt slippage like new Efka`s. The motor has a so called community drive, the control-box gives the motor the distance to run and not the synchronizer. (The synchronizer is only there to calculate belt slippage on the specific machine pulley) Then the speed reducer will mess this up.

Then you have the old type of NPS motors with the position adjusted in the synchronizer, it will run with a speed reducer but not accurate. The belt slippage on the reducer will mess up the NPS timing and makes it miss the positions. Like when it miss down position with to many degrees it will return to up position and opposite. One solution that might work is to place the synchronizer on the speed reducer, I have seen that setup but do not know if it works perfect. Depended of the particular NPS motor construction you can have a error signal, some run inaccurate and some do not run at all.

Tor

[sinpac]

My only question is doesn't the 2" or 50mm pulleys only slow down the top end speed and still will not effect the ramp up?

Chris

[Constabulary]

My only question is doesn't the 2" or 50mm pulleys only slow down the top end speed and still will not effect the ramp up?

Chris

Thats right, it just slows down the machine and increases the torque. The motor still turns at the same speed. A smaller pulley has no effect on the motor configurations.

[Constabulary]

@ Trox,

I indeed was thinking about "trying" to put the sync. on the speed reducer when I figured something is not working as expected but I don´t want to make a lot of fuss just for having the needle up or down. Maybe it will work with the new sync. - if not I don´t care. As I said, you really don´t need a sync. at low speed as you can watch the needle traveling and the motor stops immediately when I take the foot off the pedal. So what.

But always nice to get some technical input from you

[sinpac]

"Thats right, it just slows down the machine and increases the torque. The motor still turns at the same speed. A smaller pulley has no effect on the motor configuration."

@Constabulary

So I guess some folks on here might get the wrong idea when buying the 2" or 50mm pulley. It does in fact slow down the top end speed but nothing else. Most people will think it will make the foot walk at a very slow rate. I just got my Singer 211g155 back from a Industrial sewing machine repair shop. I like most was discussing the control of a clutch motor and he told me to clean and re-oil all the pivot point from the foot petal all the way up to the clutch motor then loosen the belt to the point of slipping. No it does not slow down the top end speed but it gave me more control on the ramp up to the point where I will not need to buy a servo. I must also say this machine is only for straight runs with #69 thread. My Consew 225 has a servo because I needed control wallets, journals, tack and stuff like that. So in closing I just wanted to make it clear that a 2" or 50mm pulley is not the magical cure. Practice and time and learning the habit of your clutch motor are the cure.

Edited July 13, 2014 by sinpac

[SARK9]

Some speed reducer observations and the reinvention of the wheel-

I've installed servos + speed reducers on 5 flatbed machines (3 Juki LU-563's, a Singer 251-21 and a Consew 205RB5)-- mostly to sew multiple layers of heavy webbing and ballistic nylon.

Although I've not tried every single brand and style of the inexpensive "servo" motors, many of them do seem a bit more predictable and controllable when used in conjunction with a speed reducer/torque multiplier, which lets the motor begin rotating somewhat faster before becoming loaded, notwithstanding miraculous advertising copy to the contrary. My servo motors produce 5000RPM, which I almost never need. YMMV.

Anyway, when using one of the types I'm familiar with, I find its desirable to use the smallest motor pulley available....for reasons of physical clearance (as you will see later*) as well as gaining the max reduction for your $$.

*The smaller the pulley, the further "back" towards the motor the reducer pulley can be located.

Notice the relationship between the large reducer pulley and the 50mm motor pulley...its close!

Some homemade 50mm pulleys awaitng the 5mm broach shown with a 90mm for comparison.

In order to preserve the easy of tilting your machine back for service, I have found it convenient to use an accessory mounting plate adaptor to relocate the position of my servo motors. This plate moves the motor attachment back to the rear table edge and offsets the mounting position towards the right about 0.700 inch.

This lets you mount your reducer far enough back that the new geometry allows your machine to hinge back normally and unload the long drive belt as originally designed, and helps compensate for the additional width of the reducer pulley set and its alignment with the table slot. This usually eliminates the need to lengthen or extend the table slot to prevent the belt from rubbing as well.

Here's a quick sketch of one mounting plate solution to help restore the convenient maintenance of your machine's underside when using certain reducers-

In a nutshell, there are three holes in the plate for using your table's original motor mount carriage bolts to attach it, then a couple of sets of threaded holes used to bolt on your servo in a favourable offset location. It looks very sanitary and seems to work perfectly for my stuff. [Note- I eliminated 3 of the mount holes on the drawing but didn't change the text about 6 holes. D'oh!]

-DC

Edited July 13, 2014 by SARK9