Messages

141

General Mach Discussion / Re: Servo Motor question

« on: March 18, 2011, 07:49:32 PM »

Actually I'm thinking of buying what they call a variator from them as well anyway. Apparently it's a phase converter and it would come in handy from time to time.
I wasn't planning too do this, but I am keen to use the 10,000rpm spindle motor and drive that comes with the mill and that's 3 phase only

Cheers
Dave

142

General Mach Discussion / Re: Servo Motor question

« on: March 18, 2011, 07:46:41 PM »

No, it's Ok, I asked about that too, the top line is single phase, and the second line is 3 phase, so they will take either.
Thanks
Dave

143

General Mach Discussion / Re: Servo Motor question

« on: March 18, 2011, 07:27:43 PM »

Those earlier motors with the dodgy specs were from adtech here are the brochures for the GSK motors and drive. I am a really big smoothstepper fan, since I sorted out the noise issues a few months ago the SmoothStepper has been a model of integrity. I am just about to buy another for the new mill. I was going to share a controller between the lathe and Mill, but I think that's being stingy.

Cheers
Dave

144

General Mach Discussion / Re: Servo Motor question

« on: March 18, 2011, 06:52:38 PM »

Well after a fair bit of research I am nearly back where I started servo wise. Please have a look at this and see what you think. If you think I'm making a mistake pls let me know

I've pretty well decided on the GSK 1kw AC servos and the GA98B controller. I will use non braked motors on the X and Y axis and a braked motor on the Z. The servos accept single or 3 phase 220v +- 10% so they should be fine with our single phase supply.

The GA98B servo drive accepts and I quote:
"Position mode(Position command mode: ① pulse + direction; ② CCW pulse/CW pulse; ③ A/B two phases orthogonal pulse) and External speed mode (Two external speed commands: ①－10V～+10V analog voltage command speed and direction; ② 0V～+10V analog voltage command speed of which the operation direction is selected by the input signal). "

max speed of the servos is 3000rpm with 2500rpm continuous, torque is 4nm cont 10nm max

The drive will accept pulses up to 1mhz in speed, has a 5000 lline encoder and apparently is accurate to 0.018 degrees of rotation, which should be rough enough.
 
These are almost the same as the first ones I posted Hood, which were GSK GA98As
Just waiting on final pricing for the mill, then it's all go, or should I say it's all wait for factory wait for shipping then go.

Cheers
Dave

145

General Mach Discussion / Re: Servo Motor question

« on: March 17, 2011, 07:26:39 PM »

Thanks Hood,
I hear what you are saying, but the biggest single phase servo drives I've seen are around the 1kw mark.

The ones that Russ mentioned are 240V, but once you get over 1kw they need a 3 phase input.

Not really sure why this seems to be the case, 5kw single phase VFDs  are readily available and you can draw 30 amps from a single phase 240V supply if needed which is 7kw.

If you take 25% off 7kw for inefficiency in the motors and drives and then convert the result to HP for no particular reason, other than the fact that we started life in imperial and then changed to metric, you should be able to get 7HP from single phase.
Do you estimate things in feet and mm? ie.. 2ft and about 15mm

 

146

General Mach Discussion / Re: Servo Motor question

« on: March 17, 2011, 02:38:48 PM »

Thanks Overloaded, I read through the PDF on the link you provided, it was nicely laid out and easy to understand, but unfortunately, the prices were a it high. I am in Australia and once I pay freight they would cost substantially more than the others I was looking at.

Cheers
Dave

147

General Mach Discussion / Re: Servo Motor question

« on: March 17, 2011, 04:18:41 AM »

Still haven't made a servo decision, I am thinking of running the machine on 240v single phase, which I think is doable with 1kw AC servos, but not with bigger ones. I could also use Gekko 320X drives, but it means a beefy DC supply, and probably different servos.

Please feel free to tell me what you would do.

The manufacturer recommends that I buy their sheetmetal guarding, but I am trying to get the machine from Tiawan to my shed for under $20,000.00 and the guarding is a a few grand  more.

I am trying to do this as cheaply as possible, but end up with a really good machine. If I can get this system running the way I want I may end up supplying a few of these systems

Any suggestions about the servos I should use based on the machine details below? I feel a bit lost here.

Cheers
Dave

148

Works in progress / Re: THE LATHE PROJECT - 2011

« on: March 16, 2011, 06:52:43 PM »

The screen is looking pretty full, but quite comprehensive. I was thinking about what I do when I turn the lathe on and the first thing is to reference the axis. I cant see the Home/reference buttons, but i might be suffering from selective blindness.
The rest looks good thanks Scott

149

Works in progress / Re: THE LATHE PROJECT - 2011

« on: March 14, 2011, 09:54:13 PM »

Sounds good Scott,
I am glad you're making a start. If you need some testing done, please let me know

Cheers
Dave

150

General Mach Discussion / Re: Servo Motor question

« on: March 11, 2011, 06:19:53 AM »

I don't understand the torque graph at all I think they made it up. Or scr-wed it up!