When should I go from series to parallel?

[Oldmanandhistoy]

I have a question for you stepper motor experts out there.

At what rpm is it advisable to go from bipolar series to bipolar parallel?

I know there will be other factors to take into consideration like the torque curves and construction of the machine but am looking for a figure that would be a good rule of thumb.

Thanks in advance for any input,

John

[epineh]

I guess if your RPM is causing missed steps then it might be time to make the change. If your drivers can handle the current then maybe just do it anyway, though watch the motor temps, they say they can run pretty hot (80 deg C) but I don't know if I would let my motors run at that temp.

Russell.

[mcpltd]

I would say around 450 RPM.
The attached curves were done with the same motor, driver, voltage and resolution.

I have a question for you stepper motor experts out there.

At what rpm is it advisable to go from bipolar series to bipolar parallel?

I know there will be other factors to take into consideration like the torque curves and construction of the machine but am looking for a figure that would be a good rule of thumb.

Thanks in advance for any input,

John

[Oldmanandhistoy]

Thanks for that; also interesting to see you’re nearly down to half the torque at 3000 pps. I’m working on a machine at the moment and my target cutting speed is 3m/min with my 6mm pitch that will be 500 rpm. To get good acceleration and deceleration speeds would it be best going series? I’m guessing it would be a close call on that one. I have some calculations to do for sizing of stepper motor and drive as soon as I get some hard figures on gantry weight and cutting forces required. You may be able to recommend me a stepper from your stock and a drive to match. I will definitely be going over powered to be on the safe side that way I will get some decent rapids as well.

John

I would say around 450 RPM.
The attached curves were done with the same motor, driver, voltage and resolution.

[mcpltd]

Yes go parallel.
When you have some hard data get in contact and we will see what we can do.
Runnning out of motors at the moment (All our customers keep buying our stock), but will have more stock in about 8 weeks, including a new motor based on the FL60 (3Nm 23 frame) but higher current (4.2A parallel) so the inductance will be a lot lower.

Thanks for that; also interesting to see you’re nearly down to half the torque at 3000 pps. I’m working on a machine at the moment and my target cutting speed is 3m/min with my 6mm pitch that will be 500 rpm. To get good acceleration and deceleration speeds would it be best going series? I’m guessing it would be a close call on that one. I have some calculations to do for sizing of stepper motor and drive as soon as I get some hard figures on gantry weight and cutting forces required. You may be able to recommend me a stepper from your stock and a drive to match. I will definitely be going over powered to be on the safe side that way I will get some decent rapids as well.

John

[Oldmanandhistoy]

8 weeks, I can’t wait that long. I have noticed some of your steppers are out of stock while browsing for a friend of mine. We had to look for another source not easy in the UK. I requested more details from a seller and am still waiting after nearly two weeks! So you may have them back in stock before we find a new source at a competitive price. Hopefully you will have what I need as I will be buying very soon.

John

[Oldmanandhistoy]

Actually while I think about it I may go with a servo system for the X axis of my machine. I do not know a thing about servos systems. So a quick question while I have your attention; can you use two stepper drives and one servo drive funning from a parallel port? Is the servo drive driven with pulses the same as a stepper drive?

John

[mcpltd]

I know, we have sold over 800 motors in the last two weeks, and this does not include our OEM customers.
Dont use the website to check stock, becasue we also have a large number of surplus stock, that is not on the website.

[Oldmanandhistoy]

I will keep that in mind; would it be ok to PM you here?

John

EDIT: With that information I may have to look at importing some myself.

I know, we have sold over 800 motors in the last two weeks, and this does not include our OEM customers.
Dont use the website to check stock, becasue we also have a large number of surplus stock, that is not on the website.

[mcpltd]

Depends on the driver, but the answer is yes, you can run a servo and two steppers.
But in most cases people dont do this and would normally have at least two axis running on servos and the third (Z Axis) on stepper.
You will end up paying a lot more for a servo system, but will get far better performance.

As a guide we offer a three axis brushless servo driver with 500W continuous and 1KW peak power (Per Axis) for about £900 and the motors are about £120 each.

Actually while I think about it I may go with a servo system for the X axis of my machine. I do not know a thing about servos systems. So a quick question while I have your attention; can you use two stepper drives and one servo drive funning from a parallel port?
Is the servo drive driven with pulses the same as a stepper drive?

John

[Oldmanandhistoy]

Another question for you.

What ratings on a stepper motor would you recommend , to match with all these cheap drives on Ebay (2.5A/phase and 30-35Vdc) running bipolar parallel? Not that I would touch those drives I have 4 MSD 556’s.

John

[Oldmanandhistoy]

I am hoping that I will be able to run the required stepper using your MSD980 but we will see when I have done the maths. Anyway better get on with some work or I won’t need my new machine.

Thank you for your time.

John