G251s and Warm

[haciman]

Hi.

I ask question about connect the G251s.

I have 1 piece G251s and 2 piece ims im805 microstepper drive.My motors 1.85Nm 3.2V 2.8A bipolar stepper motor (4 lead). My power supply 42V DC(unregulated).



This drivers and motors connected for test. All drivers (G251s and im805) adjusted 2.7A current.

I used trial version Mach3 for test. My motors diffrent velocity worked at the test (test time 10 minute). Only a stepper motor (at the connected G251s) warmed (approximate 30C degree). Other motors (connected the im805) not warmed.

Why this motor warm?

[Mariss Freimanis]

The IM805 uses a different method of motor current control than we do. It keeps the motor cooler but it causes more motor vibration at certain speeds. A warm motor should cause no concern unless it reaches boiling hot (100C).

Mariss

[haciman]

Originally Posted by Mariss Freimanis The IM805 uses a different method of motor current control than we do. It keeps the motor cooler but it causes more motor vibration at certain speeds. A warm motor should cause no concern unless it reaches boiling hot (100C). Mariss

Yes. G251s low speed performance is the best. No vibration and little sound. But im805 little vibration available low speed (under the 5 RPM).

Anti Resonance function writing the im805 datasheet. İs the true or not true? Do you know any users?

[Mariss Freimanis]

The IM805 datasheet says the drive uses "non-regenerative switching" on the positive current slope (sine 0 to 90 degrees) and "regenerative switching" on the negative current slope (sine 90 to 180 degrees). This is similar to what the Allegro chip-set does, and in fact it does slightly decrease motor heating compared to non-regenerative switching used in all our drives.

The downside is it introduces a serious torque discontinuity at sine 0, 90, 180 and 270 degrees. Translated, the motor vibrates or resonates at low speeds more than it should.

We have always opted for the smoothest possible motor motion. The price you pay is the motor is just a little warmer. From my point of view, that price is far smaller than bad motor smoothness. You buy and use motors from which you expect the best possible smoothness and performance.

Mariss

[haciman]

Originally Posted by Mariss Freimanis The IM805 datasheet says the drive uses "non-regenerative switching" on the positive current slope (sine 0 to 90 degrees) and "regenerative switching" on the negative current slope (sine 90 to 180 degrees). This is similar to what the Allegro chip-set does, and in fact it does slightly decrease motor heating compared to non-regenerative switching used in all our drives. The downside is it introduces a serious torque discontinuity at sine 0, 90, 180 and 270 degrees. Translated, the motor vibrates or resonates at low speeds more than it should. We have always opted for the smoothest possible motor motion. The price you pay is the motor is just a little warmer. From my point of view, that price is far smaller than bad motor smoothness. You buy and use motors from which you expect the best possible smoothness and performance. Mariss

A new im805 price 400$ in the Turkey. This driver vey very expensive. And i understood anti resonance circuit function not working for im805. My im805s outback product. I paid 110$ for 2 piece. At the same time, baby gecko performance is the best and cheap than the im805.

G203V my dreams stepper motor driver. If i necessary money save up i purchase.

[Crevice Reamer]

Originally Posted by haciman G203V my dreams stepper motor driver. If i necessary money save up i purchase.

Buy the G540. You will get 203V performance (albeit at 3.5A and 50V) at much less price. You will have to save up less to get G540 than G203Vs

Maybe there are still some left right now, at the overstock special price of $225:

http://cnczone.com/forums/showthread.php?t=72628

CR