[sprintcar72]

Does anyone have any experience with the Schneider Electric Lexium MDrive closed loop steppers? If so, what are your thoughts? I have not obtained any pricing yet, but am curious how it compares to separately purchasing a stepper, encoder, and driver. They have a four year warranty as well.

Lexium MDrive .::. Schneider Electric Motion USA

[UA_Iron]

I have used a number of mdrive2 in my career. From what I gather for the lexium mdrive is that the closed loop functionality really is to maintain the synchronization over anything else - so the motor won't stall out if the power requirement is too high. This is accomplished by reducing speed - which may cause problems with coordinated motion.

“The closed loop functionality in Lexium MDrive products is accomplished with a hardware-based system we call hMTechnology or hMT. This control algorithm won’t allow the motor’s rotor and stator to lose synchronization, so unintentional stalling is eliminated. Blending enhanced performance with an overall robust design, Lexium MDrive products are a good fit for a wide range of industrial automation applications.” According to Paul Kling, Vice President Sales, SEM USA. For more on hMT, click here


I think for the CNC application, many people have had luck with the leadshine closed loop steppers:
Leadshine Nema23 Hybrid Servo Closed Loop Stepper Drive Motor Kit 3PH 2nm 57mm | eBay

those will be cheaper per axis than the lexium stepper.

If you want to do closed loop steppers and truly servo them, then copley is your best bet:
Copley Controls - Accelnet - Servo Drive - Servo Amplifier for Brushless & Brush Motors - CANopen - CAN bus - EtherCAT
Copley Controls - Stepnet - Stepper Drive - CANopen - CAN bus

The stepnet plus you can utilize a dual closed loop motion utilizing a motor encoder and linear encoder. The motor encoder becomes velocity control and the linear encoder becomes the position feedback device. Standard stepnet utilizes only motor encoder.

With the current gain you can squeeze nearly 40% more torque than the rated value of a stepper motor momentarily. You also don't have to worry about motor sizing as your gains will just power through deadzones. You will want to use a fine microstepping resolution with these controllers.

[WindMiller]

Any updates?

[sprintcar72]

All I could get from my local Schneider distributor was that "Lexium closed loop steppers are expensive ". From what I can see from other builds, the hot ticket is Teknic Clearpath servos. I think I may be headed in that direction.


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[WindMiller]

All I could get from my local Schneider distributor was that "Lexium closed loop steppers are expensive ". From what I can see from other builds, the hot ticket is Teknic Clearpath servos. I think I may be headed in that direction.


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Thanks for answering, that was pretty much the same conclusion i came up with also.

[sprintcar72]

The Teknic website says they only want to support OEMs, yet there are a lot of folks out there installing them on home machines. I am curious if they are getting help from Teknic with motor selection and support. They seem well documented, but I am not clear on how to size the "stepper killer". All I find on the website is that they are two to three times more powerful than a stepper.


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[WindMiller]

Have you checked out these guys on Youtube yet?

NEO CNC Talks about the Clearpath Servo. (Sounds promising)
https://www.youtube.com/watch?v=Z2kAcz-rG5s&t=1022s

And

NYC CNC Also talks about the Clearpath Servo. (Sounds really promising to)

https://www.youtube.com/watch?v=3TzNQnSKO_8
https://www.youtube.com/watch?v=ZRURwDFvdAs

I contacted Teknic last year about buying a ClearPath servo and no problem there, just contact them!

[James Newton]

I don't really think using steppers with feedback makes a lot of sense.... the point of a stepper is that it works without it; at the cost of less power and higher cost. If you have feedback, use a DC or AC motor (BLDC) with a servo controller to get more power at lower cost.

[Jim Dawson]

They seem well documented, but I am not clear on how to size the "stepper killer". All I find on the website is that they are two to three times more powerful than a stepper.

Just use the same torque rating as you would in a stepper. The ClearPath has a nearly flat torque curve, rather than one that drops off rapidly like a stepper. I installed 4 ClearPath servos on a customer MultiCam router. Very easy to setup and tune. The customer only machines aluminum, and it is working out very well.

I don't really think using steppers with feedback makes a lot of sense.... the point of a stepper is that it works without it; at the cost of less power and higher cost. If you have feedback, use a DC or AC motor (BLDC) with a servo controller to get more power at lower cost.

If I were building a new machine, I agree. But I had a customer that couldn't hold part tolerance on his machine, but didn't want to retrofit with servos, so I installed linear scales on the table and the Z axis. Then tied the scales back to the controller and wrote an on-the-fly position correction algorithm to correct the position. Works just like a BLDC servo.