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Matt S

Ho Hsing G60 servo or what?

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I've got a few different servo motors from the cheaper end of what's commonly available. However, as impressive as most of them may be, and as perfectly fine for garment machines as I'm sure they are, they all seem to be lacking something or several things, for my purposes. Mostly these are a limited pedal speed range and/or an excessive starting speed. I understand that these are pretty much par for the course with cheap servo motors.

I've gone down the speed reducing pulley route before and the results are impressive. However I want to be able to use a needle positioner/synchroniser and would prefer to not have the bulk under the table. It doesn't help that I am in the UK so a lot of options are simply not options (we use 230ish volts @ 50Hz mains).

The Ho Hsing G60 servo has been recommended by several posters on here as having good low-speed performance. At £200ish including tax and shipping it's nearly double what the cheapest servos cost and the synchoniser is extra so I'm a little hesitant about pressing the trigger until I'm fairly convinced it's the right option. Specifically I'm looking to power my Seiko LCW-8 (very similar to the Consew 226) and want to be able to run it from under 100SPM to over 1000SPM without adjusting any settings (a wide pedal range with lots of discrete steps along the slope).

(Another thing other than price I'm not too keen on with the G60 is that it's a 2-button interface. I find them tricky to navigate, and would it really kill the manufacturers to put on a speed knob and a few toggle switches for commonly changed settings? I'd love a nice robust 3-way toggle for the synchroniser, and maybe a "safety" that disables the motor for making adjustments around the needle without fear of putting a Schmetz #160 through my finger without having to turn the power off? But I digress...)

Am I asking too much for a bottom-end servo motor? Is there a better option, hopefully for fewer beer tokens? I really don't think I could stretch to an Efka... Should I just give in and build my own PLC-controlled direct-drive stepper setup?

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Replace the handwheel with a (much) larger pulley. I'm assuming you have the smallest pulley you can on the motor? This will give you a considerable speed reduction and allow the use of the needle synchroniser,

This is my Seiko. I did the same on my Pfaff 335.

 

 

Seiko 8a.jpg

Edited by dikman

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8 hours ago, Matt S said:

 

Am I asking too much for a bottom-end servo motor? Is there a better option, hopefully for fewer beer tokens? I really don't think I could stretch to an Efka... Should I just give in and build my own PLC-controlled direct-drive stepper setup?

I just received today a motor from Keystone sewing that fits the bill. At least so far I think so.

https://store.keysew.com/sp-1100-npfl

A nice amount of torque, 100 rpm start, dual position synchronizer (you can adjust both the high and low needle stops), a fairly simple menu and bonus points for a simple +/- speed control buttons on the front. (100-2500 rpm) Also has one outlet for LED light and one for 24v foot lift solenoid. The menu has dozens of adjustable parameters - even braking strength.

I did a preliminary mounting on my Juki 2810 and with the included 50mm pulley it buried the needle in anything I could fit under the foot and it has a nice modulation in speed. Slow ramp up and no sudden drastic steps in velocity.

Very impressive so far!

I might throw the reducer back on but I'm not even sure it needs it now, at least not for torque. It's slow but maybe not slow enough. I might just need to get used to it.

Haven't installed the synchro yet but it's a nice unit, much better than the one I've been running.

Chinese import, so maybe it's avail in your neck of the woods?

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9 hours ago, dikman said:

Replace the handwheel with a (much) larger pulley. I'm assuming you have the smallest pulley you can on the motor? This will give you a considerable speed reduction and allow the use of the needle synchroniser,

This is my Seiko. I did the same on my Pfaff 335.

Unfortunately I can't do that as it confuses the synchro. I've already got a 40mm wheel on the motor which gives me a 2:1 reduction to the machine.

3 hours ago, R8R said:

I just received today a motor from Keystone sewing that fits the bill. At least so far I think so.

https://store.keysew.com/sp-1100-npfl

Chinese import, so maybe it's avail in your neck of the woods?

That looks just the sort of thing I'm after but it's 110volt only! Solenoid output would be very handy.

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14 hours ago, Matt S said:

I've got a few different servo motors

The Ho Hsing G60 servo has been recommended by several posters on here as having good low-speed performance. At £200ish including tax and shipping it's nearly double what the cheapest servos cost and the synchoniser is extra so I'm a little hesitant about pressing the trigger until I'm fairly convinced it's the right option.

How bout this?

https://www.kornetshop.com/deutsch/elektromotoren/servo-motor-jm822-650w/#cc-m-product-7750616786

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4 hours ago, Kohlrausch said:

Oooo we have a contender! Have you used this motor? Do you know what size shaft it has -- perhaps I could swap a 40mm pulley onto it? That'd give me a lowest speed of 50SPM, which is less than one per second -- ideal!

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Your other option, and I end up doing this all the time with electronics (cameras etc) is buy the Ho Hsing and if it doesn't work out for you, ebay it. If you end up losing a little money consider it a rental. Right now I have 2 motors that I'm probably going to sell after finding this new one, its that good. Sometimes you have to eat a bit of cash to find exactly the right equipment.

4 minutes ago, Matt S said:

Oooo we have a contender! Have you used this motor? Do you know what size shaft it has -- perhaps I could swap a 40mm pulley onto it? That'd give me a lowest speed of 50SPM, which is less than one per second -- ideal!

That one is 650 watts. You might be disappointed in the torque unless you're using a reducer.

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3 hours ago, DrmCa said:

650 watts is plenty.

Depends on who makes the motor. Often the claimed watts on a servo motor is almost meaningless in my experience. I've used a 550w motor that had cranking amounts of torque and great low speed control, whereas I recently installed a claimed 1400 watt motor that had lousy control and struggled with needle penetration on slow stuff.

I'm trusting trial and error more than listed specs these days. The 1100 watt motor I posted, while maybe not even a true 1100 watts, definitely has "umph". Much more so than a motor with even higher wattage stamped on it.

Maybe contact Keystone and see if they have a lead on a 220v version?

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19 hours ago, Matt S said:

Unfortunately I can't do that as it confuses the synchro.

Oh? Have you tried it? It should work as the ratio between the two pulleys is constant, whereas fitting an intermediate speed reducer means the ratio varies as far as the synchroniser  is concerned. That will definitely cause issues (well, it did with mine).

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3 hours ago, dikman said:

Oh? Have you tried it? It should work as the ratio between the two pulleys is constant, whereas fitting an intermediate speed reducer means the ratio varies as far as the synchroniser  is concerned. That will definitely cause issues (well, it did with mine).

I haven't tried this particular setup no but the issue is the overall number of turns the motor has to make before the synchro registers a rotation. More than 3 or so and many motors (including a couple I have) stop with an error code. I don't think it matters how this ratio is reached whether it's a 40mm pulley motor direct to a 240mm machine pulley or if there's a 3:1 reducer betwixt the two. Some motors tolerate it, most don't.

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Fair enough. Personally, I found that once I'd slowed everything right down for sewing leather I didn't need the synchroniser, if anything I found it to be a nuisance. I can see where they would be an advantage for high speed sewing, particularly with small stitches, but in my case it would sometimes give an extra stitch and with larger stitch spacing the last thing I needed was an unwanted extra hole!

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4 hours ago, dikman said:

Fair enough. Personally, I found that once I'd slowed everything right down for sewing leather I didn't need the synchroniser, if anything I found it to be a nuisance. I can see where they would be an advantage for high speed sewing, particularly with small stitches, but in my case it would sometimes give an extra stitch and with larger stitch spacing the last thing I needed was an unwanted extra hole!

If that works for you in your application, great. I've used machines fitted with a speed reducer before and they can work fine. However I use the synchro to stop the machine needle down, which massively helps me in making backtacks and corners -- I hardly need to touch the handwheel. It might sound silly but even at a second per handwheel operation there's enormous time savings to be made by using  a well-featured motor. The main purpose for this machine is to sew 1-3 (usually 2) layers of 2mm waxed chrome leather with TKT20/V138 thread with ~3mm stitches. On a standard 4ft dog lead that's about 10ft of sewing so I like/want/need to have a fast speed available -- so long as the quality stays just as good more speed is more profit, or a lower price for my customers. I sew at the minimum speed when I'm doing the fiddly bits, which with the best motor I currently have is 500RPM/250SPM (40mm motor pulley, 80mm handwheel). Hence why I'm shopping for a replacement and have a fairly specific set of requirements.

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In my opinion having a needle positoner and commanded to return a needle to up position or vice versus from your particular setup is really nice. 

With most of these servos as in price under 250.00, have more difficulty if in the reducing pulley systems.  Some however I believe can do some! Operations within reduction of 4.75 : 1. 

Allthough full operations or abilities of typical positioners is not available, to my limited present knowledge.

One interesting step I found with little testing is the needle positioning with a typical Heel application. This I have not been able to “Re-accomplish” as before a reduction system like previously setup with. 

These are all benefits I like, and or liked before reduction. But life must go on. If I could have just one of these benefits I would choose to better the one step/stitch fuction.  As in the “standard” tapping of the foot pedal for this operation to be fullfilled. 

This should be one stitch and Never 2, this would have to be my priority. I dont believe this can be accomplished with present switch assemblies. 

 

Good day

Floyd

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Btw I tried out a reducer on that SP-1100 motor I posted and it worked great, positioner worked fine with it. I ended up removing it though as the 100 rpm start was fine and I will prob put the reducer on another machine.

Of all the motors I've looked at or used, this one is a winner. Great balance of power and utility vs cost. Other motors with similar power and low speed control have extra features I didn't need and it drives the cost up (auto back-tack, trimmer, etc)

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3 minutes ago, R8R said:

Btw I tried out a reducer on that SP-1100 motor I posted and it worked great, positioner worked fine with it. I ended up removing it though as the 100 rpm start was fine and I will prob put the reducer on another machine.

Of all the motors I've looked at or used, this one is a winner. Great balance of power and utility vs cost. Other motors with similar power and low speed control have extra features I didn't need and it drives the cost up (auto back-tack, trimmer, etc)

I sent Gregg an email about the SP-1100, it sounds like a real winner. I don't strictly need a solenoid output yet but it opens some possibilities  for the future. Better to have it and not need it, as they say. 

2 hours ago, brmax said:

In my opinion having a needle positoner and commanded to return a needle to up position or vice versus from your particular setup is really nice. 

With most of these servos as in price under 250.00, have more difficulty if in the reducing pulley systems.  Some however I believe can do some! Operations within reduction of 4.75 : 1. 

I agree completely, a synchroniser/positioner is a hugely useful thing so long as it's reliable/repeatable. Takes a big chunk of donkey work out of machine sewing. As you say some servos will tolerate a speed reducer, whereas others won't. Difficult to guess which will though -- manufacturers rarely even give proper motor specs like torque, let alone things like minimum speed and what reductions they'll tolerate. I guess that's what we suffer though, considering what a tiny %age of a limited market we represent.

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Thanks for clarifying things Matt, now I understand where you're coming from and can see where a synchroniser would be a real asset.

I just spent some time on Aliexpress trying to find that "German" motor (I wondered where they sourced it from). I was looking for that particular control panel, but the only match I found didn't have a synchroniser, although it did come in 600 and 800w models. Unfortunately my Chinese is non-existent so I couldn't make any sense out of the instructions!

Edited by dikman

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10 hours ago, dikman said:

I just spent some time on Aliexpress trying to find that "German" motor (I wondered where they sourced it from). I was looking for that particular control panel, but the only match I found didn't have a synchroniser, although it did come in 600 and 800w models. Unfortunately my Chinese is non-existent so I couldn't make any sense out of the instructions!

Thanks for taking the time to look, Dikman. I've tried the same a few times, on both Aliexpress and Alibaba, and often come up with a partial match at best. I suspect that end-user distributors can spec certain changes over a moderate minimum order size -- nothing too drastic like a different shaped casting, but a change of pushbutton layout or a tweak of some of the component specs wouldn't be difficult to do with today's CAD/CAM machines. That would go a long way to explaining why most distributors of any size seem to have different flavours of the same motors.

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I also had a look at Alibaba but so far haven't found anything like it. I did find one with the knob control and a couple of push buttons next to it which looked interesting. If I need another one sometime I might consider it.

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Matt, I hate you! You piqued my curiosity, I knew the synchroniser wouldn't work with a pulley reduction system (I tried it), but you got me thinking "did I actually try it with a (very) large pulley?". So I just spent all day to prove it one way or the other - and you're right (unfortunately). I had to make a new sleeve to fit the pulley to the shaft as I needed it more accurate than the existing one and also machined the end to take the synchroniser. Took most of the day! Then I had to move the control box from the left side of the table to the right side 'cos the cable wouldn't reach. While I was at it I swapped the motor and controller over, as one of my tables had a 750w motor which I felt would be better on the Seiko. So at the end of the day I tried it and found after 1 1/2 stitches it stopped and gave an error message indicating a synchroniser problem. The two pulleys, by the way, are a 1 3/4" on the motor and an 8" on the head.

I wonder at what ratio it stops working?

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I´m also wondering if there is a setup with speed reducer that makes the NP work. 

Trial & Error science - I love it... go on please :popcorn:

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18 minutes ago, Constabulary said:

I´m also wondering if there is a setup with speed reducer that makes the NP work. 

Trial & Error science - I love it... go on please :popcorn:

I was using an Artisan ACF-652C with a standard reducer wheel. Worked really well as long as you kept the top speed somewhat controlled. It didn't like trying to brake from over 2500 rpm - it might add a stitch or two before burying the needle but it was consistent if you kept the speed realistic. Never had a positioner error though.

 

This one btw -

http://artisansew.com/pdf/ACF-625cInstructionManual10_2017.pdf

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1 hour ago, dikman said:

Matt, I hate you! You piqued my curiosity, I knew the synchroniser wouldn't work with a pulley reduction system (I tried it), but you got me thinking "did I actually try it with a (very) large pulley?". So I just spent all day to prove it one way or the other - and you're right (unfortunately). I had to make a new sleeve to fit the pulley to the shaft as I needed it more accurate than the existing one and also machined the end to take the synchroniser. Took most of the day! Then I had to move the control box from the left side of the table to the right side 'cos the cable wouldn't reach. While I was at it I swapped the motor and controller over, as one of my tables had a 750w motor which I felt would be better on the Seiko. So at the end of the day I tried it and found after 1 1/2 stitches it stopped and gave an error message indicating a synchroniser problem. The two pulleys, by the way, are a 1 3/4" on the motor and an 8" on the head.

I wonder at what ratio it stops working?

 

52 minutes ago, Constabulary said:

I´m also wondering if there is a setup with speed reducer that makes the NP work. 

Trial & Error science - I love it... go on please :popcorn:

I believe it's a feature to detect broken or slipped belts -- a bit like when the machine jams -- obviously a firmware issue, and as such each model of motor is unique with regards to how much reduction it'll tolerate. I think most servos will tolerate a 2:1 reduction, as I currently have. Reports vary as to which models will tolerate a 3:1 or greater reduction with a synchro installed. Clearly some do, as they are supplied fitted to machines like the Cobra 441 clones. It's another characteristic that motor manufacturers don't publish that would be hugely useful to us leatherworkers, but I guess we're a tiny sector of the market, as usual.

I'm leaning more and more towards building a MCU- or PLC-controlled stepper, like @Uwe made. I'd get total, full-power control from 0RPM and all the fancy features I want. Problems would be the time I spend on it and reliability. Component cost would be a about equal with one of the better entry-level servos.

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Could be a fairly involved project, Matt.

I guess my next step is to replace the motor pulley with a 3" and see if that works. This will give me a ratio of 2.67:1 compared to the current 4.5:1. I don't particularly need the synchroniser, but now that I've invested this time and effort it would be nice to get it working.

And I need to know.........

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