Re: [CAD_CAM_EDM_DRO] Question about servo motors

Hi Bryan

Well, the servo size is in the ball park- it depends on the speeds
and accelerations you want. Servos will give superior performance.

Note that the stated spec of 22c/watt thermal resistance is
in error I think. Decimal place is missing or something.
As a wild guess I would figure the continuous stall torque
of these motors would be in the 150 in oz range. You can
prob hunt the full specs with a web search.

As far as price... well it seems ok. I've seen lower. I still sell
a few new SEM 1200 in oz servos with tachs for about the same
price. They have twice the torque but to be fair one must spend
$50 more for an encoder. The combination of tach and encoder
feedback can give superior low speed performance though.
I think the Gecko 310 can do this. They are an ok match to
the Gecko 310, 320, and 340 as well as Copley 412.

I would not recommend the SEM motors for a mill drill though.
They are designed for use with a Bridgeport type machine.
In fact they are installed on many. I use them for a large
gantry type machine.

As far as the leadscrews go there are many discussions in
past posts about this. I will give only two words of advice:
Use ballscrews!

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: "bkpryor" <bkpryor@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, November 12, 2002 10:18 PM
Subject: [CAD_CAM_EDM_DRO] Question about servo motors


> first of all, I'm a newbie and I need lots of help. I found these
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1787258271&rd=1
> motors on ebay. is $480 a good deal for 3 servos with a peak torque
> of 600 oz.in.? If not, where can I find a better deal? Will these
> motors have sufficient torque to convert a dovetail mill/drill to CNC
> without replacing the acme leadscrews with ballscrews?
>
> also, would the gecko g320 be sufficient to run these? What are some
> advantages of the g340 over the g320? What type of power supply
> would I need to run these with the gecko g320 or 340?
>
> I'm still pretty unclear as to exactly what I need as far as the
> electronics go to control the CNC. Any help would be appreciated.
> --Bryan