Messages

961

Tangent Corner / Re: Stepper motor Inductance ?

« on: May 11, 2012, 02:41:23 PM »

well.... I know there's inductors which can be used to alter a circuits inductance and I know there's potential dividers that drop voltages... but whether thay can be used to do what you need is beyond my pay scale. 'twould be interesting to know though. If you're on the zone I reckon you should ask in "stepper motors and drivers" - maybe Marris will come forth. I reckon he's your man for this. Be sure to keep us informed though - interesting question.

Ian

962

General Mach Discussion / Re: easy motor tuning

« on: May 11, 2012, 02:34:06 PM »

Correct Ian, personally I prefer to calculate the steps per, but maybe I am unusual that way

Nope - me too - never actually used the calibration thing.

Ian

963

General Mach Discussion / Re: easy motor tuning

« on: May 11, 2012, 01:17:20 PM »

You can use the mill screen for the tuning, but, make note of the values and use them in the turn screen.

RICH - do you NEED to do this? i.e. note the values. The values are surely stored in the xml NOT the screen. We're only using the mill screen for the button. The xml will still be the lathe xml. Yes/no?

Ian

964

Tangent Corner / Re: Stepper motor Inductance ?

« on: May 11, 2012, 09:39:17 AM »

Maybe with special considerations that I have not found yet ? Some do have finned alu heat sinks attached.

I'm thinking you're on the right track there Russ. Here's a snip from gecko's stepper blurb after stating the 32*sqrt(L) rule.

As shown earlier, motor output power is proportional to power supply voltage, doubling the voltage doubles the output power. However, iron losses outpace motor power by increasing non-linearly with increasing power supply voltage. Eventually the point is reached where the iron losses are so great that the motor cannot dissipate the heat generated. In a way this is nature’s way of keeping someone from getting 500HP from a NEMA 23 motor by using a 10kV power supply.

Ian

965

Tangent Corner / Re: Stepper motor Inductance ?

« on: May 11, 2012, 08:18:40 AM »

just noticed that according to the spec sheet that things at 170Vdc - wooooooohhhhhhaaaaaaa - waaaaaaaay too much for a 2mH motor. However much you can turn down the current I reckon you still have the makings of a good toaster 

Ian

966

General Mach Discussion / Re: easy motor tuning

« on: May 11, 2012, 07:44:32 AM »

1024.set is the one with the calibration button on.

1024.lset is the standard lathe screen - all .set and .lset files are in c:\mach3

re: how far from where? - from where it is.

Ian

967

Tangent Corner / Re: Stepper motor Inductance ?

« on: May 11, 2012, 07:27:13 AM »

Hi Russ - That's why I said at 2mH your supply voltage *should* be around 45Vdc but what voltage power supply are you ACTUALLY using?

Ian

968

General Mach Discussion / Re: easy motor tuning

« on: May 11, 2012, 05:25:42 AM »

Hi Fred - re-inventing the wheel again? 

You're on the right lines but there is a procedure built into Mach to do this all for you.

goto the "settings" screen and bottom left hit the "set steps per unit" button. If you're using a screenset that doesn't have this screen or button then just temporarily load the standard 1024.set via the "view" menu button - do the biz and then reload your original screenset. Voila!

Ian

969

General Mach Discussion / Re: home switches

« on: May 11, 2012, 03:55:40 AM »

Your BOB provides 5 inputs. How they're labelled is irrelevant. As long as you set Mach up to match you could (if you wanted) use P10 for E-stop P11 for Zhome P12 for Limits etc. etc. whatever you want - your BOB neither knows nor cares.

Ian

970

Tangent Corner / Re: Stepper motor Inductance ?

« on: May 11, 2012, 03:40:53 AM »

Russ - you say the drive "puts out" 130V. Do you mean your power supply is 130V? If so that's WAAAAAAAAY over for a 2mH inductance motor. Voltage should be around 45Vdc tops.

That said - I think your heading for an ultimate burn-out here - if the drive and motor matters to you I'd heed the manufacturer's warning.

Ian