variable speed motor or pulley system

[Ringneck]

If a motor has a 3 step pulley set up which runs 1000 at the slowest setting is this slow enough for good control? I hear that variable speed motors and controllers are the way to go, but how slow does one usually run them? I am planning on buying the variable speed motor but want to hear your thoughts.

Thanks,

Shawn

 

[Plain ol Bill]

I am using the finer grits after heat treat so slow you can see the joint of the belt coming around most of the time. My fingers don't get burned up as much this way (grin)

 

[Brett Bennett]

You can calculate your surface feet/minute (SFM) with the following formuala: Diameter of drive wheel in feet X Pi (3.14) X RPM of the contact wheel. Remember, with a pulley setup you may need to add another muliplier. For example, if you have a 2" pulley on your motor and a 3" pulley on the drive wheel shaft, you will need to multiply by 2/3 to get the correct shaft speed.
You may want to get two step pulleys to give you more options. I would want to cut speed in you example roughly in half if using an 8" drive wheel.

Brett

 

[R Dockrell]

Shawn
I have been using a multitude of pullys for years.
My drive motor is a 2HP 1725 RPM baldor. My drive wheel on my 2inch belts is 5 inch dia. I have a step pully shafted to it through two bearing blocks. I can change the drive pully on my motor from 1.5 inch up to 8 inch. I have never figured out the belt speed but, on slow I can read the writing on the backside of the belt as it goes around. On fast it is just plain scary, and I stand to the side as it winds up to max speed. But I'll tell you it profiles and hogs like crazy.
I beleive pullys are cheaper and much more versitile than a VS motor. You can't increase the speed of your motor drive unless you use pullys.

 

[Harry Jensen]

My setup is a 2" X 72" with a 10" contact wheel...on the wheel shaft I have a 4 step pulley in 3", 4", 5", & 6"......and off the 5HP motor shaft a sheave of 4 - 4" pulleys.......couldn't find a step for the 1 3/16" shaft off the motor....forgot the SFPM but goes slow and fast enuf!
Harry