Re: [CAD_CAM_EDM_DRO] SCR motor control, didi-key scales and my new mill drill

Although most of my tools have standard 3 phase induction motors
some have scr dc controls.

I put a 1.5 hp GE statrol shunt dc motor on the small vertical
bandsaw and It works great. I run it with a dart control that
cost $150. It even has tach feedback, but I am just using
ir comped back emf feedback right now. If I get a little
resonance in the blade I can change the speed a little
to eliminate it. Just turn the dial.

I can't claim that torque and speed are independent, but it
is good enough to cut steel or wood without any pulley
changes. That is a 10:1 speed change or so.

The big dc motors can be expensive though- but I got
some for free. I think the ge motor cost $800 new with
control. If you are buying new I would consider a variable
frequency inverter and a 3 phase induction motor- no
brushes to wear out.

But for hobby use you can usually find something on
ebay.

Les

Leslie Watts
L M Watts Furniture
Tiger, Georgia USA
http://www.alltel.net/~leswatts/wattsfurniturewp.html
engineering page:
http://www.alltel.net/~leswatts/shop.html

----- Original Message -----
From: "Joe Barnes" <toblave@...>
To: "CAD_CAM_EDM_DRO" <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Wednesday, August 28, 2002 11:59 PM
Subject: [CAD_CAM_EDM_DRO] SCR motor control, didi-key scales and my new
mill drill


> I just picked up a grizzly Mill-Drill at an auction, with 2 Acu-Rite DRO's
> and a fairly old Wood's SCR motor and controller.
>