Ho Hsing G60 servo or what?

[dikman]

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).

[Matt S]

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.

[dikman]

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!

[Matt S]

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.

[brmax]

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

[R8R]

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)

[Matt S]

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.

[dikman]

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 September 29, 2018 by dikman

[Matt S]

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.

[dikman]

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.