Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: sshneider on November 21, 2005, 11:43:36 PM

Title: Spindle Speed Control- how do it do dat? (newbie question)
Post by: sshneider on November 21, 2005, 11:43:36 PM

Hey all,

Some of my questions seem so lame I'm almost embarrassed to ask.  Thanks in advance for your patience.

Question... What piece of hardware interfaces with my driver board/Mach 3 will control the speed of my spindle?

FYI- my spindle is a Porter-Cable Router.  I have been using (please don't laugh too hard) this little Barney McGee potentiometer speed controller between the relay output and the router :o.  After seeing that Mach has the capabilty to control spindle speed, I feel like a Caveman who has just been shown fire.

Could someone please describe what I should do to interface my Router?  Thanks much!

Sid

Title: Re: Spindle Speed Control- how do it do dat? (newbie question)
Post by: Brian Barker on November 22, 2005, 05:11:31 AM

Please don't be embarrasses! We all had to start at the someware...
There are a few ways to run the spindle... There is a DigiSpeed that is a cool way to go! There Bob's spindle speed board, I think CNC4PC  has one , PLC's and you can make one. Any of them are going to output an analog comand 0-10V or 0-5V. Is there a speed control that you can add an external pot or comand too? If there is you but one of the boards and hook it up!
Here is the CNC 4 PC board http://cnc4pc.com/Variable_Speed_Control_Board.htm it is a low cost board that should help you...

Hope that gets you a little closer
Brian

Title: Re: Spindle Speed Control- how do it do dat? (newbie question)
Post by: sshneider on November 22, 2005, 11:11:59 AM

Thanks Brian.  Now, I get it.  Basically the driver board is triggering an interface board which in turn operates the VFD, which powers a 3ph spindle motor.  This all makes sense.  I kinda go lost because my Router (spindle) is your basic "plain jane" 110v Single Phase which is not traditionally controllable with VFDs.  I thought maybe I had missed something along the way in Electrical evolution.  I guess if I want to have full spindle speed control, I'm going to need to rethink my router/spindle motor set-up.

Thanks a bunch for your response!  ;D

Title: Re: Spindle Speed Control- how do it do dat? (newbie question)
Post by: Bloy on November 23, 2005, 12:31:52 PM

I too am using a 115Vac router as my spindle.  I was wondering if that potentiometer you are using now could be attached to a small stepper or servo motor with appropriate drive and then the position of that pot could be controled by step and direction commands.  I would imagine that the control position of the pot/motor would need to be calibrated? 
  There is also the question of maintaining torque when in the lower speed range.  I am guessing that a higher quality speed control would have the electronics to provide that needed low rpm torque. ....or maybe AC routers just can't respond. 
  just thinking out loud.....or not thinking at all.

Title: Re: Spindle Speed Control- how do it do dat? (newbie question)
Post by: Brian Barker on November 23, 2005, 06:42:42 PM

IS the pot that it is running the speed just changing  0- 10VDC? If it is you will not need any of the other stuff :)

Brian

PS Yea I have let out the smoke  ;D 

Title: Re: Spindle Speed Control- how do it do dat? (newbie question)
Post by: sshneider on November 25, 2005, 12:30:33 PM

Bloy- I like the way you think.  It's a clever idea to do what you suggest.  I think I'll give it some more thought and see if there is a way to streamline the implementation.

Brian- The potentiometer is basically a really small "Variac".  I think all it is doing is creating resistance.  I'll take a closer look to see exactly what is going on there but, I'm sure it's not doing anything in the DC voltage domain.

Title: Re: Spindle Speed Control- how do it do dat? (newbie question)
Post by: Bloy on November 25, 2005, 03:21:05 PM

Sid,
  I can't think that that speed control is simply a variac type .   I believe there must be some electronics to control those 115Vac motors...although I think they are considered AC/DC motors..of which I still don't understand. :)

Title: Re: Spindle Speed Control- how do it do dat? (newbie question)
Post by: sshneider on November 25, 2005, 03:44:58 PM

Well, I'll be the first to admit that I'm not expert on the electronics/electrical aspect of things.  I know just enough to be dangerous.  Here is a link to the device I'm talking about ... http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=43060

Please don't laugh TOO hard  :D.  The funny thing is.. this little doodad actually works pretty good. 

The real solution would be installing a 3 phase spindle motor, getting an AC inverter drive and controlling it through the device that Brian suggested.  Unfortuneately, it's a heck of a lot more expensive AND I'm not really sure how to adapt a collet (bit holder) to a standard motor shaft.  There is probably some kind of couple out there that will do it.  All of that just sounds like a ton of work when you are already set up with a 115VAC router.  It's like going backwards 3 steps to get ahead 4.

Doesn't anybody manufacture/sell a compact 3 phase router complete with Collet? 

THAT would be SWEET!  8)