How do the Tradeoffs Work? - Steppers for Horizontal Rails

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ray_parkhurst
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Re: How do the Tradeoffs Work? - Steppers for Horizontal Rails

Post by ray_parkhurst »

Wow, 7lbs seems like a lot. But I guess with camera, lenses, bellows or whatever, it all adds up. I'd estimate my load on the KR2001 at around 2.5lbs and I have never needed extra braking beyond the stepper detent torque.

Doppler9000
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Re: How do the Tradeoffs Work? - Steppers for Horizontal Rails

Post by Doppler9000 »

ray_parkhurst wrote:
Tue Sep 21, 2021 5:15 pm
Those Zero Detent Torque motors are very iteresting. I can see them being useful for horizontal systems, and the zero torque would make accurate microstepping much easier.

For most horizontal systems, very little torque is needed.
Which motor would you choose?

https://www.linengineering.com/products ... 417-series

mjkzz
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Re: How do the Tradeoffs Work? - Steppers for Horizontal Rails

Post by mjkzz »

it was part of testing

ray_parkhurst
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Re: How do the Tradeoffs Work? - Steppers for Horizontal Rails

Post by ray_parkhurst »

Doppler9000 wrote:
Wed Sep 22, 2021 2:13 pm

Which motor would you choose?

https://www.linengineering.com/products ... 417-series
What size motor mount did your linear rails come with?

Doppler9000
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Re: How do the Tradeoffs Work? - Steppers for Horizontal Rails

Post by Doppler9000 »

ray_parkhurst wrote:
Wed Sep 22, 2021 5:16 pm
Doppler9000 wrote:
Wed Sep 22, 2021 2:13 pm

Which motor would you choose?

https://www.linengineering.com/products ... 417-series
What size motor mount did your linear rails come with?
NEMA 17 for both, though the KR26 has NEMA 23 adapter plate as well.

ray_parkhurst
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Re: How do the Tradeoffs Work? - Steppers for Horizontal Rails

Post by ray_parkhurst »

Doppler9000 wrote:
Wed Sep 22, 2021 5:56 pm
ray_parkhurst wrote:
Wed Sep 22, 2021 5:16 pm
Doppler9000 wrote:
Wed Sep 22, 2021 2:13 pm

Which motor would you choose?

https://www.linengineering.com/products ... 417-series
What size motor mount did your linear rails come with?
NEMA 17 for both, though the KR26 has NEMA 23 adapter plate as well.
Honestly, I'm not a huge fan of Lin's newer products, or of ordering them directly. The only Lin motors I've had good luck with are the 416 series with dual shafts, which are not easy to spec on their website. I prefer Vexta motors, and can recommend a few model numbers, but I generally use their PK243M-01BA. It is a discontinued product, but they are usually available used or new on eBay or other sites. They are dual shaft, medium torque (28 oz-in), and low voltage so they work well with 12V controllers. Here is a link to the spec sheet:

https://catalog.orientalmotor.com/item/ ... k243m-01ba

Here's an example on eBay:

https://www.ebay.com/itm/264803402868?h ... SwKeBfFvi9

Their detent torque is reasonable, and gives enough resistance to rotation that my KR2602 with ~2.5lb vertical load does not slip.

Doppler9000
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Re: How do the Tradeoffs Work? - Steppers for Horizontal Rails

Post by Doppler9000 »

mjkzz wrote:
Wed Sep 22, 2021 1:39 am
OK, just for the purpose of education, here is an experiment one can perform:

Get a step motor, say a bi-polar one, not powered up, try to turn the shaft with fingers, one would feel certain effort to turn it.

Now, connect the two wires for the same phase together for both phases, forming closed circuit, try to turn the shaft again, what do you expect? I am sure many here know this and I will keep it interesting for people to experiment.

Now, connect that motor to a step motor driver, before powering it up, feel the torque, for SOME driver, you would feel the same as if the wires were connected, for some OTHER drivers, it would feel like open looped one, meaning as if the motor is not connected to anything. To power down a step motor driver, mostly is to inactivate the EN pin (either low or high), some driver might disconnect power from the motor, forming an OPEN loop, leaving the motor in detent state.

However, keeping the driver in a low current state means keeping the motor in a closed circuit loop, for either type of driver, hence avoiding detent state.

Anyways, I am just trying to provide some fun info here because it was fun for me when I played around with step motors.
Great experiment!

It’s nice to be surprised like this.

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Re: How do the Tradeoffs Work? - Steppers for Horizontal Rails

Post by mjkzz »

yes, a lot of surprises :-) pushing it a bit more, get two 200ohm (if you use 12V power supply, 10ohm for 5V) resistors and connect them to the motor in series, so now the motor is powered with "little" current (about 50ma-60ma), now try to turn the shaft and compare it with the setup with phases shorted.

Solely relying upon detent torque in a system design is not a good idea, it might work for a particular setup, but not for all. It is a good idea to anticipate such situations particularly for system designers, and possibly beneficial for end users as well -- more options exploring different setups.

Anyways, I think I have disclosed too much design considerations here, but these are the fundamental things I would expect, so be it. But I will shut up now :D

Doppler9000
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Re: How do the Tradeoffs Work? - Steppers for Horizontal Rails

Post by Doppler9000 »

ray_parkhurst wrote:
Wed Sep 22, 2021 7:16 pm

Honestly, I'm not a huge fan of Lin's newer products, or of ordering them directly. The only Lin motors I've had good luck with are the 416 series with dual shafts, which are not easy to spec on their website. I prefer Vexta motors, and can recommend a few model numbers,
Hi Ray,

It is easier for me to buy new from Oriental Motor, so can you please recommend some current (PKP24?) options?

Vertical KR2001 rail.

ray_parkhurst
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Re: How do the Tradeoffs Work? - Steppers for Horizontal Rails

Post by ray_parkhurst »

Doppler9000 wrote:
Wed Oct 20, 2021 11:16 am
Hi Ray,

It is easier for me to buy new from Oriental Motor, so can you please recommend some current (PKP24?) options?

Vertical KR2001 rail.
The closest equivalent to what I recommended above is the PKP243MD15B2. Here is the spec sheet:

https://catalog.orientalmotor.com/item/ ... p243md15b2

This assumes your motor mount is NEMA-17. Unfortunately, Oriental Motor does not seem to make a 0.9-deg NEMA-14 any more, but they do make a NEMA-11, the PKP225MD15B:

https://catalog.orientalmotor.com/item/ ... kp225md15b

So you have an option if your motor mount is for NEMA-11.

Here's a link to the operating manual:

https://www.orientalmotor.com/products/ ... 443-9E.pdf

I do recommend their clean damper. It acts to smooth the operation as well as provide a nice knob for manually turning the dual-shaft motor. Here's a link to the D4CL-5.0F for 5mm shaft motors:

https://catalog.orientalmotor.com/item/ ... /d4cl-5-0f

edited to add: I also see that the new line of motors does not come with integral cable assemblies, so you need to buy a cable. Here is their 2ft cable:

https://catalog.orientalmotor.com/item/ ... es/lc2b06a

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