Servo motor install on brother machine

[rivercityleather]

Hi! I recently purchased a Brother LS3-C53 that came with a clutch motor. Think I’ve figured out which servo to buy but I’m also seeing talk about a speed reducer and need positioner. I thought the servo allowed me to reduce the speed, sewing stitch by stitch if needed. Am I wrong here?? Do I need something in addition to the servo motor to be able to adjust speed? Please forgive my inexperience. And thanks in advance for any tips!! They are greatly appreciated.

[GerryR]

I used an AC variable frequency drive on a Singer 153 that I had and was quite happy with it.  The drive ran a 1 hp 3 phase motor (definitely overkill) and you could make the needle crawl, so you could stop the needle anywhere and didn't need a positioner.  When running an AC drive at slow speed (lower than line frequency) it runs in "constant torque" mode, so there is plenty of drive to penetrate thicker materials (over line frequency, it runs in constant hp mode).

DC drives tend to run at much higher RPMs, and there torque curves are different than AC drives.  I think that is why people use speed reducers, to get the motor to a more acceptable RPM-torque level and get more range from the foot pedal.  I personally prefer the AC Variable Frequency  Drive (VFD) over the DC drives that I have used, but your mileage may vary.  It might be worth a look at though.

One other point: AC VFDs can run off single phase power, but put out 3 phase power for 3-phase motors.  

[kgg]

Replacing the clutch motor is the important step in being able to consistently control the stitching speed of your machine. I would try just replacing the clutch motor first with a servo motor (min. 550 watt) and if you find you need more torque or even slower stitching speed then add a good quality speed reducer. The only caution I could add is if you add a needle positioner before adding a speed reducer you my find depending on how much reduction you added it may not work properly. Some people really like the needle positioner while others not so much. Guess it depends on what you are sewing. Personally I don't use one. I have never really needed such items as a needle positioner or laser stitch line guide and think of those items as just something else that could go out of alignment.

kgg

[Northmount]

Moved this thread to Leather Sewing Machines.

 

[dikman]

A servo is definitely the way to go, as kgg said try it as is first and if it still doesn't give you the control you want then add a speed reducer. I found a needle positioner wasn't really much use for my style of sewing (slow!) as I can control the needle without one, plus some of them don't work when a speed reducer is fitted.

[Pintodeluxe]

I've had all variants mentioned and here is my experience with it.  A 550 watt Family / Tech sew style servo does pretty well if you swap the motor pulley.  They often come with a 75mm pulley, and you can easily swap them for a 45mm pulley from eBay.  Not quite stitch by stitch, but close.

To that setup I've added a box style speed reducer which allows you to crawl stitch by stitch.  Or you can sew at normal speeds.  The benefit of the speed reducer is it allows you to crank up the power on the servo motor.  Plus it acts as a torque multiplier.  

The downside of a speed reducer is the extra mechanical drag if you do handwheel occasionally.  Even with the pedal slightly depressed (to release the cork brake) you'll feel more passive resistance to rotating the hand wheel.  

As far as the needle positioner, you need a servo with a digital display panel to run a positioner.  I dislike those motors and they're a pain to set, compared to a simple dial.  I like a needle positioner for high speed non-walking foot machines. But I find no use for them with leather.  

Like others here, I recommend starting with a Family / Tech Sew style servo with a single mechanical dial to adjust speed.  Add a speed reducer later if needed.  You'll likely be happy without one.  Especially if you pop for a small pulley.  Last time I looked they were about $2.  

Best of luck with it.