Re: [CAD_CAM_EDM_DRO] Re: Has anyone done one of the R/C motor spindles?

whelenremington wrote:

>--- In CAD_CAM_EDM_DRO@yahoogroups.com, "vrsculptor"
><vrsculptor@h...> wrote:
>
>
>>Has anyone done one of the brushless R/C motor spindles yet. I'm
>>curious as to how it worked out and what motor/controller you used.
>>Thanks,
>>
>>Roger
>>
>>
>
>Roger, I havn't done one but I've been wondering about the same
>thing. Hans Wedemeyer at http://hans-w.com has a link "DC Motor
>Speed Control" on his site but I don't know if it will control a R/C
>dc motor.
>

Brushed RC motors are just regular DC motors, and probably would not be
suitable for a spindle motor. They typically aren't designed for
extended run-times, so I'd expect them to wear out or require frequent
maintainance. They would be easy to control, either with a standard RC
ESC, or with a custom system.

>I don't know
>much about the performance characteristics of the R/C dc brushless
>motors, but I have been wondering why they would not be useful as
>high speed spindle motors for PWB drilling applications. And as you
>have asked, how do you control their speed and get dc current to
>them. Maybe someone will help us out with some answers.
>
>

Brushless RC motors are more interesting. To control them you'll need a
brushless ESC (electronic speed controller), this is useful because it
is designed to control the motors speed based on standard RC PWM input.
Basicly, you feed it a pulse train every 14-20mS with a pulse width of
1520 microseconds. To control the motor speed in either direction you
adjust the pulse width by up to +/-600 microseconds. This can be
generated directly from the parallel port.

A low-end motor and controller of the sort you would find in a 1/10th
scale vehicle would run about $170, with more powerful systems ranging
up to several hundred. The low end systems (such as the Novak Super
Stock system :
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXGDP6&P=ML ) come with
a 175W motor, Kv 4300 rpm/v Kt 0.45 oz-in/amp. Maximum voltage is about
8.5v, so around 36kRPM max. For another $40 you can step up to a
faster, more powerful motor.

High-end motors and controllers will process quite a bit more power
(65Acont/90Apeak at 15v), with rpm limits about as high as you want to
go. They tend to be designed for larger RC cars and aerobatic planes.
These will set you back $500-600 for a new system.

There are also much smaller motors, but they tend to be set up for small
planes, so they run slow with lots of torque, I don't know if they'd be
suitable for a spindle motor.

Check out
http://www.hackerbrushless.com/
http://www.castlecreations.com/
http://www.teamnovak.com/

Hope this info is useful,
Dave K