NEMA 23, weird velocity results.. need help

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21 Nov 2013 04:11 #41049 by fannlow
Using stepconf to up the velocity as you suggested and here is the new .ini file.

Though in stepconf I set max velocity to 135mm/s, in .ini, I see that max accel is cap at 128.251613306mm/s

Now testing slow jog,
Max doable without stall or missstep is 785mm/min.
Safe bet is around 750mm/min or any place lesser is ok.
However, stepper isnt turning as if its much faster?
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21 Nov 2013 04:27 #41050 by andypugh

Max doable without stall or missstep is 785mm/min.
Safe bet is around 750mm/min or any place lesser is ok.
However, stepper isnt turning as if its much faster?


Notice that this is mm per minute and the INI file values are mm per second

750mm/min is 94mm/sec, which does sound like an improvement.
It is 420 rpm, which is about what you can expect from a stepper at 36V. (perhaps a little low)

Have you checked the voltage into the drives at max motor speed? (I think you reported the voltage at the motors, but that is chopped by the current limiter, so can't really be measured with a multimeter.

Did I mention that my lathe only manages 25mm/sec and is entirely acceptable to me?
The following user(s) said Thank You: fannlow

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21 Nov 2013 04:33 #41052 by fannlow
750/60sec = 12.5mm/s?

:(

It is 3mm/s faster, I would say :laugh:

But it is faster.
So, the default speed in .ini is around 13.5mm/s, while max is 135mm/s (unattainable)

How do I measure how many volts is going through?
And where do I measure it?

What should I be getting?

Thanks

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21 Nov 2013 05:19 #41054 by fannlow
Using the calculator

3A, 6.8mH & 36.6V from the driver board to my motor,
I can turn max at 4.49rev/s, 1.11 min time/step & 110watts.

Pushing the driver to
4.2A, 6.8mH & 36.6V from driver board to motor,
I get lowered rev/s @ 3.2 & 154watt...

Seems like getting the driver board around 3A will actually help my speed?

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21 Nov 2013 05:27 #41055 by andypugh

750/60sec = 12.5mm/s?

Ah, yes. Don't know where I got my number from.

How do I measure how many volts is going through?
And where do I measure it?
What should I be getting?


Measure at the output of the power supply, just to be sure it is maintaining the voltage.

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21 Nov 2013 05:30 #41056 by andypugh

Using the calculator
3A, 6.8mH & 36.6V from the driver board to my motor,
I can turn max at 4.49rev/s, 1.11 min time/step & 110watts.


Sounds about right, unfortunately.

You might actually get better speed with shorter steppers with a lower inductance. It is the inductance that is preventing the motors spinning faster by the sound of things.

How many wires do your steppers have? If they are 8-wire then you might be able to re-wire in parallel config for more speed.

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21 Nov 2013 05:35 #41057 by fannlow
Jz 4...

www.longs-motor.com/productinfo/detail_12_25_114.aspx

23HS9430...
They have just come out w a new version using 4.2A & 3.8mH induction!!
Wasnt there half a year ago when I purchased...

So, will running the average 2.37A on my driver DIP be able to help me go faster?
But im losing torque right? Hope will work since im cutting foams..

Suggestions?

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21 Nov 2013 05:37 #41058 by fannlow

750/60sec = 12.5mm/s?

Ah, yes. Don't know where I got my number from.

How do I measure how many volts is going through?
And where do I measure it?
What should I be getting?


Measure at the output of the power supply, just to be sure it is maintaining the voltage.


I took the voltage at the driver inlet from psu, consistent at 36.6V.

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21 Nov 2013 05:45 #41059 by andypugh

So, will running the average 2.37A on my driver DIP be able to help me go faster?


No, and I don't know why the calculator says that it will.

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21 Nov 2013 05:46 #41060 by Rick G
Look at the motors torque curve. And the rpm that the torque falls off, usually quite rapidly.
If you are trying to run the motors pass that point you are sure to be disappointed.

Rick G

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