Are stepper motors rated peak current or RMS current?

[tauntdesigns]

I just bought a Leadshine MX3660 from Automation Technology inc. It has dip switches to adjust the drivers' current and step.

The chart in the manual, gives settings for both Peak and rms current. When a motor is rated 1.8a, is that rms or peak?

I read on the web somewhere........... that all stepper motors' ratings are in rms........

Thanks for any info,

Similar Threads:

• Help!!! Peak or RMS current?
• Newbie- Why 1/2 or 2/3 of rated current?
• Problem- KL34H2160-62-8A Specification Price: $179 ( in stock) Rated Current: 4.4A, Rated
• Stepper Motor (Rated Current ?? )
• rated current per phase

[tauntdesigns]

In the similar threads: I saw a thread for, "Help!!! Peak or RMS current".

My earlier search didn't bring that up... Oh well.

I'm not sure the question got answered or not, but someone did say that motors are rated at peak current. Which was opposite of what I read earlier on the web(everything on the internet is true, right).

Oh well, off to read more,

[tauntdesigns]

Most of the threads that I've read have had posts stating both ways..... some say motors are rated peak current and others say they're rated at RMS current.

But. I've came across a few sites that say all stepper motors are rated RMS. So, I'll set the MX3660 for the RMS setting.

One of the sites I went to was Leadshine. I looked at their stepper motors and read one of the pdf's. In that pdf I saw a paragraph that gave the current settings for rms. I then went to their specs chart and checked the current rating and they were the same as the rms rating in the pdf.

Later,

[tauntdesigns]

Anybody

[KOC62]

This question was answered in this thread; http://www.cnczone.com/forums/steppe...current-2.html

[tauntdesigns]

This question was answered in this thread; http://www.cnczone.com/forums/steppe...current-2.html

Yeah, I read that thread a couple of times. I also read a few posts that felt differently.

But, I think I see what the(my) confusion is. At full-step the Peak and RMS is the same........ micro-step 1.414A peak = 1A rms (Peak/1.414=rms)

Now, I'm curious why my drive has both Peak and RMS reading for the DIP switches?

Thanks for the reply,

[KOC62]

When you calculate the root-mean-square of a sinewave current through a resistance over one cycle period you get a value that is mathematically the same as a dc current going through the same resistance. The dc current is steady, thus equivalent to the peak current.
A stepper using full steps has a current flow that is a peak current for each step. When you use micro-stepping mode the waveform starts to deviate from dc and become more sinusoidal with increasing microstep sizes. A 125 microsteps is practically a sine wave in shape. An AC current is expressed as RMS.

I would assume that your controller can be setup for microstepping. It is in this mode that it makes sense to use RMS for current control.

[tauntdesigns]

After reading the Leadshine stepper motor pdf, I got confused again. lol

They rate their motors in RMS and calculate for peak current if you are using the motors in half-step or full-step.

I guess there is no standard to the manufacturer's specs, because I've read people saying that motor ratings are listed in Peak and others saying that they are listed in RMS(leadshine does).

Thanks again for the responses,

[tauntdesigns]

Leadshine pdf was taking their listed current and multiplied it by 1.414 to get peak current to run half-step or full-step.

[KOC62]

At the end of the day you want the setting that can do the work but heats the motor the least.
Wish you the best in your progress.

[tauntdesigns]

Sounds like good advice
and
Thank you.