[ErnieH]

Ger21,
Of course!!! It is 2020 after all!!! I have found a few with the lowest being 5.5mh. That's half of what I have now. I have been searching for a small 34. The ones I have are 118mm and stick out a bit.

My m3 does not seem to act that way. With 1 I can here it wind up and wind down. With 5, it just goes..... ZOOM!! Either seems to match the motor tuning graph. Maybe I have a bad setting someplace else?

I still have question from earlier..
So when I use the online Speed and Power calculator, should I use the supplied voltage and ignore the motor voltage? I just don't know how the input voltage could affect motor speed without frying the motor. I'm old school.....

[ErnieH]

And accel is not the issue, just random stalls. Load does not matter. Just moving or dragging my butt around, it either stalls or does not.

[ErnieH]

Duplicated previous post.

[peteeng]

Hi Ernie - Its a machine and there's nothing random on a machine. You just have to be systematic check everything, assume nothing. A stepper uses magnetic coils to work. Current produces magnetic density hence torque. More current more torque. Voltage drives the coils and because there are coils near coils they generate back voltage (back vmf). The faster the stepper goes the more back emf produced, at some point the back emf equals the driving voltage so the motor stops. The electronic drivers job is to manage this issue and to manage the current steps. A stepper driver is a complicated relay. I don't think you need a new motor you just need to sort what you have.. Keep at it - Peter

[peteeng]

Hi Ernie - Don't use any calculators. Set everything to small values and get an understanding of the motion. Check velocities and distances are correct. Then slowly bring speeds and accels up until you get to your targets or the machine complains somehow. "Random" stalls if electronics and settings are reasonable often is mechanical. Loose couplings, bad bearings, tight something... check everything, assume nothing. cheers Peter

[ErnieH]

I have been playing with it for a couple of week now. Changing steps, m3 settings, etc. I have not changed the amperage yet. I did read someplace where that my be an issue to. Maybe if I drop it down an amp or two, it will play better. I don't think I need all that torque.

[ErnieH]

I walked through everything. The bearings were a bit loose, so I tightened them a touch and it went from 55 to 60 IMP.... Woo Hoo!! Again, it's on all axis'

[ger21]

So when I use the online Speed and Power calculator, should I use the supplied voltage and ignore the motor voltage? I just don't know how the input voltage could affect motor speed without frying the motor.

Stepper speed calculators won't really give you an accurate answer. Too many variables installed.

The drive restricts the voltage to the motor. The higher voltage is used to "force" more current through the motor faster. So higher voltages will give you more speed.

If it stalls with an accel of 5, then you should lower the accel to maybe 2 or 3. Whatever allows you to go faster. Just be aware that low acceleration values will have their own issues.

Your best option is to probably get motors like I recommended and change couplers.

[ErnieH]

Acceleration is NOT the issue. I can set it at whatever I want without issue, however, I never went above 5 because of the torque on the system.

The issue is it will move a bit and then stall. At random locations and at random times. If it was consistent, I have a hammer and can fix it!!!

I have to overdriving the steppers, so my only option is to get new ones like you recommended. I am still looking. I want to be as close to plug and play as possible.

[ErnieH]

I ordered 3 of these. 3.5mh on inductance. 34HS31-5504S. We will see what happens when I get them.

[ger21]

These would have been better, and cheaper. https://www.omc-stepperonline.com/ne...ter-mm%5B14%5D

[ErnieH]

Yes they would have, had I seen them. The only downside is they ship from China, so it would be awhile before I got them. You just can't do enough research........

With any luck (ha ha), I should have the ones I ordered by Friday.

[ErnieH]

Woo Hoo!! What a difference a low impedance motor makes. I went from 60 IPM to 250IMP, way more than I will ever use. One last problem.... The Y axis screw is making some weird noises, so I need to see if I can find a new drive nut(??) and a way to check to see if the balls in it are messed up.

Thanks again for all the help!!! I really appreciate it!!

[asuratman]

So you have velocity about 250 IPM (+4X) after you changed motor with 3.5 mH. Big effect just because smaller inductance.

[ErnieH]

Yes. I had been looking for a reason for a lack of speed since day one and then I hit a post on here that mentioned inductance as the problem. It's the only place I have ever seen any mention of it. Seems to me that would be in more posts all over the internet.

GER21 found me better steppers (2.5 mh) at Stepperonline, but it was after I ordered some and they did not have any US stock. At least they tell you if there are any in the US.

[ger21]

Seems to me that would be in more posts all over the internet.

A lot of people on the internet don't know what they are talking about...

[ErnieH]

That's a fact!!! Do X. NO!! do Y. You both are stupid, do Q......

[joeavaerage]

Hi,
as an answer to a previous question you posted 'why use a 60V power supply (and drive) when the stepper says 2V ??'

If you had a low voltage supply and adjusted it to 2V and had that hooked to the windings of the stepper then the rated current (4.4A or whatever)
would flow through the windings. If you adjusted the power supply to 4V then double the rated current would flow and you would potentially damage
the windings.

When you hook a 60V power supply to the stepper the current would, without the aid of the driver, go through the roof and the power supply and stepper
would likely be destroyed within microseconds. One of the functions of the driver is to switch on and off very rapidly the power supply such that the average
current is maintained at rated current rather than go through the roof.

Only when the motor is stationary does this situation apply, when the motor is moving the current is applied in one direction and then in the other direction as each step
is taken. Under these circumstances the inductance of the windings impedes the current flow and the drive plays little part in regulating the current flow to safe levels.
Ideally the current would reverse in the winding instantly and this would in turn allow very many steps to be taken in quick succession, ie rotate very fast. Inductance
means that the current cannot reverse instantly and therefore the rate at which successive steps can be taken is limited. Having the highest possible voltage
to 'drive' the current in the reverse direction is a time honored means of reversing the current quickly and consequently spin the motor fast.

Using a high voltage driver is trying to overcome the inductance of the windings, the actual average voltage applied to the windings is in fact very low, around 2V
its just at the moments of current reversal that the high voltage supply is used to its max. Best bet to assure high speed operation of a stepper is to select a design
with the lowest possible inductance in the first place.

Craig

[ErnieH]

Joeaverage, Still not sure of the answer.... If my motor takes 2v, why would the torque curves reference a 60v supply? I understand E*I=W, but..... Since the power supply has the amps needed, voltage should not come into play. Just can't remember much from my electrical engineering from 35 years ago...... So the stepper takes my 60vdc and converts it to the number of pulses needed to rotate the motor at the desired speed. Does the driver spike the pulse voltage as the torque requirements go up? If I remember right, a square wave with a 60v peak will provide a 30v average. Is the average what they are talking about?

[peteeng]

Hi Ernie - Yes its all about the averages and the backcurrents. The driver is just not putting current onto one coil, its putting syncronised & variable positive and negative currents on adjacent coils (microstepping) for very short periods of time. Inductance controls the inrush and outrush currents, less inductance less electrical inertia. More voltage more "force" overcoming the inertias short high pulses very low averages. Gecko have a couple of white papers on their site I think explaining microstepping. Peter