New stepper motors?

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BOJO
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New stepper motors?

Post by BOJO »

Hi,
I have an old ISEL Gantry table and have just replaced the old ISEL Control rack with a new
based on Axemotion Pulsar and Gecko G230V. Using KAY for driving the machine.
I have not changed my old round motors and are having trouble getting more speed without loosing steps
especcially on the Z-Axis that is rather Heavy with a Suhner UAL 23 1850W spindle.

Will I benefit a lot changing to new Square steppers? Looking at NEMA 23 type with and without brake.
I have a brake for the Z-Axis.

PaulRowntree
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Re: New stepper motors?

Post by PaulRowntree »

The magnetic field of old round motors (like the SloSyns) decrease over time, but the newer squares are more stable.

You won't be able to use the Gecko (203?) to their full power with the NEMA23 motors. The 2013 can drive at up to 7A, while the NEMA23's are usually limited to ~3-3.5 A
http://www.geckodrive.com/geckodrive-st ... rives.html
Paul Rowntree
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mike1966
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Re: New stepper motors?

Post by mike1966 »

nema 34 motors have a lot more power and will work with the gecko drives.I bought mine from cncrouterparts.com they are 7.5amp 960oz only $150

BOJO
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Re: New stepper motors?

Post by BOJO »

Thanks for your answers.
I have found adapter plates so that I can use NEMA 34 steppers on my NEMA 23 mounts.
It will add about 1 kg to my Z-Axis but more than double the torque will handle that I suppose.

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martin54
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Re: New stepper motors?

Post by martin54 »

If your looking at nema 34 motors to take advantage of the geckos output then you would be best looking at changing your power supply as well, not much point spending money on decent drivers & motors & then running them at 30v DC
If you putting together a system it is best to try & balance the components you use.

BOJO
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Re: New stepper motors?

Post by BOJO »

I just found Nanotec NEMA 23 motors with 3 Nm torque 4,2 A
Then I will not have to modify my motor mounts and can use my existing end switches.
I just need new couplings as my shaft is 1/4" and the new motors 8 mm axis.
I Think that these may be a good match for my machine as I have 1,1 Nm old steppers today.
My powersupply is 48V 10A and I that will fit also for these motors?

But will this make difference? I need smoother action for 3D work and more torque for my Heavy Z axis (motor 4,8 kg).

Theoretically these motors are almost 3 times the torque and I dont Think that my old motors are up to the original specs.

PaulRowntree
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Re: New stepper motors?

Post by PaulRowntree »

Check out the Gecko site... there is a lot of information there on matching the components. In particular, this page

http://www.geckodrive.com/support.html

is a treasure trove of information. There is a formula (REALLY badly formatted) about 2/3 of the way down that SHOULD read

V power supply in volts = 32 x sqrt( Winding Inductance in milli-Henrys )

My guess is that the strong motors have high inductance, and therefore require a higher power supply voltage to get optimal performance. With 48V, the optimal inductance is only 1.2mH.

Cheers!
Paul Rowntree
WarpDriver, StandingWave, Topo and gadgets available at PaulRowntree.weebly.com

BOJO
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Re: New stepper motors?

Post by BOJO »

That formula gives 57 V maximum for these motors wired in parallel.
So probably that would work with 48V.

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martin54
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Re: New stepper motors?

Post by martin54 »

That seems a bit strange because most of the nema 23 motors will run up to about 80v, I have 2-4.4 & 1-3.1 Nm motors on my machine running at about 70v DC.

BOJO
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Re: New stepper motors?

Post by BOJO »

According to the specs:
http://www.sorotec.de/webshop/Datenblae ... 8L3008.pdf
These are 3.2 mH wired in parallel.
Maybe I am missing something here, othervise these seem to be a good match for My machine.
32*sqr 3.2 = ~ 57 V

BOJO
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Re: New stepper motors?

Post by BOJO »

Now I have ordered the 3 Nm Nanotec steppers with an original brake for the Z-axis. I will report back with the results. Will it be a big difference to my old round steppers?

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Re: New stepper motors?

Post by PaulRowntree »

There is no way to answer this, without having the old and new motors side by side to compare.

You could easily hook up a lever arm to each shaft and measure the holding torque with a set of fish scales. Turning torque is tougher to measure, since you want to know the entire torque vs rotation speed curve. I think you will have to ask the CNC machine for this answer ...
Good luck!
Paul Rowntree
WarpDriver, StandingWave, Topo and gadgets available at PaulRowntree.weebly.com

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