speed reducer

[MikeC5]

I thought I would share the set up I just completed on my 111.  It's an 8" large pulley and 2" small for a 4 to 1 reduction.  I tried it first with the original clutch motor but it was still hard to go as slow as I wanted.  I installed the servo motor and an quite happy with the set up. 

[catskin]

On ‎9‎/‎8‎/‎2007 at 9:05 PM, Art said:

Hi Pat,

Servo Motor produces full motor power at any speed since you can have a closed loop and Variable Frequency Drive and the Hall sensor to allow for as much or as little current as required to maintain the desired speed.

AC motors only have their power when running at the rated motor speed e.g. 1725 or 3450 rpm. Clutch motors run at rated speed and engage through a clutch when you push the pedal down. You can "feather" the clutch a bit like a car (except they work in opposite directions) but basically when the clutch is fully engaged the machine is running at full speed.

To way overly sinplify (and incorrectly to boot)

Servo = Automatic Transmission

Clutch = Manual Transmission.

The basic home sewing machine motor is (or used to be) an AC motor with a potentiometer foot control of various designs that varied the voltage. The only time you get full power is when the pedal is to the metal, anything under that drops the voltage and hence the power (power that you need for leather), it scrubs this power off as heat and that is why your foot control gets hot when you run the machine slow. This would not work well in an industrial situation and that is why industrial machines have a table with the motor underneath and full speed motors with plenty of power.

Since the 80s, you will occasionally see computer controlled DC motors on the higher end home sewing machines.

AC motor home machines just don't develop the power at lower speeds and are only really good for 6oz or less at slow speeds. Constant use on heavy leather (even if the machine head is built like a tank) will eventually toast the motor though. If you have one of those baklite button controllers, sew with your shoes on because slow speed running will get that thing hot enough to blister your tootsies.

Art

Art , I think your comparison might be even closer if it were  Clutch= manual transmission and  Servo = hydrostatic  transmission.  I wrote this before I read all 5 pages but still think some might understand what I mean.

Edited February 12, 2017 by catskin
Had not read all 5 pages before writing