Another Speed Reducer Question

[Cobra Steve]

We use a ball bearing driven speed reducer on all of our equipment along with a full brushless digital servo motor, meaning that there is NO mechanical brake that will wear out and need to replace. With our system, when you take your foot off of the pedal the current stops and so does the motor. I have never liked servo motors with the mechanical brake because it costs extra money to replace and repair. We try to keep it as simple as possible for the customer.

[Davidstryingtosew]

I use 3:1 reducers with 1275rpm clutch motors. works great for me. I personally like to hold the handwheel and feel the clutch slipping. But I'm sure the same thing can be done by setting the belts loosely with a servo. I had a servo motor and just didnt like fussing with it. But it was a cheepo motor, so I cant really compare between it. I am planning to buy a quality servo motor next month to try it out again. Just need to save more money. The clutch motors are huge and getting everything set up can be a challenge, but not impossible. You may have to drill new holes and move the motor location, but thats it. I have a video of a Juki 562 with a reducer/ clutch motor and a 2" pulley on the motor. It doesn't show the set up, but you can see how the machine behaves: https://www.youtube.com/watch?v=n3H_SHMAn-Q

[Evo160K]

The Singer 45K53 that I purchased recently came with a servo motor, something new to me. So while searching LW and the internet recently for information on operating and controlling servo motors, I came across these outstanding videos on modifying the speed gradient on servo motors. They made a huge difference.

It will be better if you watch the first video before the second, the second will make more sense.

http://www.swflholsters.com/358/sewing-servo-motor-diy-smoother-speed-control-mod-paper-gradient/

Edited January 23, 2016 by Evo160K

[hercules]

I saw those videos as well, but am a little confused. Is the stock configuration a piece of transparent material with shading, or what? And is he changing the transparency, the shape, or both?

[Evo160K]

Hercules,

My Singer and servo were pre-owned, the servo had an obviously modified card in it, so I don't know what was in there originally. I suspect the card shown at 10:44 of the first video is what they look like from the factory. It appears to be a piece of paper or card. After spending some time making and shading a card to my liking, I learned the less light getting to the "receiver" end of the light beam, (the top I believe), the faster the machine will run, and since the beam is round you can't just block out the light by cutting a straight edge through it.....that may not give you the gradient/control you want. So he seems to be changing the transparency by shading with a pencil and changing the shape. Good thing about it, with patience you can set your speed to start and progress any way you like. It's really quite amazing how you can modify your servo.

[Darren Brosowski]

As we are talking about the ultimate ratio between the motor and machine shaft you also need to consider the balance wheel.

Industrial machines like the 206RB usually have 2 1/2" to 3" machine pulleys but a 45k has a pulley three times or so the diameter so it runs at one third the speed for the same motor.