Question for Stepper Motors Experts...

Hi,

I am upgrading my 4030z CNC machine EL Cheapo stepper drives (24V) to something more reliable Leadshine DM542E (driven at 48V) , genuine direct sale from Leadshine USA.

I read that the high speed torque is better at 48V vs 24V.

I couldn't find any specs (regarding this part number) beside what the seller gave me. He doesn't have more information than this.


http://msn.elcouz.net/stepper_specs.png


The leadshine DM542E drivers allow for multiple current settings... which one should I chose for my 3 axis steppers?

Should I go with RMS or PEAK current setting? From the stepper motor part number I see 2.5A...


http://www.cnczone.com/forums/attach...d=383598&stc=1


Last question, does doubling the voltage will double the wattage? I feel this is a lot to dissipate for such small stepper motors. (from 2.5Ax24V to 2.5Ax48V)

Thank you very much!

Regards,
Laurent

RMS and Peak are kinda the same just the RMS is 70.7% of PEAK current value.

My motors are 3.0A and use 36V and the 2.5A selection, not have to switch RMS/PEAK.

This is how you calculate watts

Watt = Volt × Amber

Quote:

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Originally Posted by greekart

RMS and Peak are kinda the same just the RMS is 70.7% of PEAK current value.

My motors are 3.0A and use 36V and the 2.5A selection, not have to switch RMS/PEAK.

This is how you calculate watts

Watt = Volt × Amber

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Let me reformulate my question: Which current values are used in the part number (57BYGH76-2.5A) RMS or PEAK? I need to know what is the standard labeling on stepper motors to set the correct current value according to the table on the stepper driver.

If I set the driver to 2.5A RMS does it mean it will cut-off at 2.5A? I am trying to figure out if the small stepper will really use 120 watts of power under load or this is just a limiter. I know stepper are not very efficient...120 watt of power is a lot to dissipate.

Quote:

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I am trying to figure out if the small stepper will really use 120 watts of power under load or this is just a limiter.

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Steppers don't work like regular motors, so you don't get anywhere near 120watts of power. The higher voltage is used to force the current through the motor faster, allowing it to have more torque at higher speeds.

Set the drives to 2.5A peak.

What should be the safety margin power supply wise ?

I have ordered a LRS-350-48 (48V 7.9A) thinking I should have at least 10A supply because 2.5A x 3 axis = 7.5A which is very close to the maximum current the PSU can supply.

The PSU specs can allow 110-140% of rated power before faulting.


Thank guys!

With modern drives, you only need about 70% of the total current, or 7.5 x 0.7, or about 5.25 amps from your power supply. So your 7.9 amp supply is fine.

Quote:

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Originally Posted by ger21

With modern drives, you only need about 70% of the total current, or 7.5 x 0.7, or about 5.25 amps from your power supply. So your 7.9 amp supply is fine.

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Thank you for the fast and precise answers!! :)

Have a nice day!

Laurent