[MikeCaffey]

So i have put in just over a thousand hours on my machine now and have experienced my first big issue, the z axis motor stops working when trying to move it at and decent speed. When it stops working i have to restart my control box to get it going again.

I am running a nema 34 960oz with g 203 driver. This issue started last week right before i blew out my ballnut, do to a spindle stall during a plunge, so I replaced the ballnut. Now the stalls have gotten worse, and and i cant run the machine without the z axis stalling. I am guessing that my stall during the plunge was the final kick to my motor. I went ahead and ordered a new motor, one that is a little bigger. 1200oz. My z axis is a little more heavy then most diy machines, so i am hoping the larger motor will help keep it from going bad if that was the issue. Before this all happened i did notice my z motor gets hotter to the touch then the other axis.

I hope the motor is what went bad and not the driver, has anyone had something similar happen? I am running a full production machine, so downtime is killing me!

Another thing i am wondering is will uping my motor size lead to any other issue? My current motors are 960oz running own a 21a 48v power supply. i got the cnc router parts nema 34 diy electronics kit.

Thanks,
Mike

[awerby]

Stepper motors are pretty tough; it's rare that they are at fault in a typical failure. It's more likely to be a driver going bad. While the G 203V drivers are top of the heap, they aren't immortal (although they might be undead..). Have you tried connecting that lead to another motor and testing whether it exhibits the same faults?

Motors with more holding torque (which is usually what's meant by "bigger") usually have more inductance, which can lead to problems. While the 960 oz-in motors might work adequately on that 48v supply, the 1200 oz-in one might want more power to run as well. Fortunately, the 203V can take up to 80v, so you should be able to upsize your power supply without a problem.

[MikeCaffey]

I tried connecting the lead too the Y axis and still the same problem. so i believe that rules out driver error.

I am able to turn the ballscrew with my fingers to raise the axis. the stalls happen at random parts of travel, so the bearings seem to be rolling free.

Here is a video i just took, let me know what you think of this awful sound. https://youtu.be/MGEsGzhvtm4


Here are specs of the motor i ordered and my current motors. Is rated current the same as peak current? It kind of throws me off that the bigger motor says it takes less amps.

Manufacturer Part Number: 34HS46-5004D
* Motor Type: Bipolar Stepper
* Step Angle: 1.8 deg.
* Holding Torque: 8.5Nm(1204oz.in)
* Rated Current/phase: 5.0A
* Phase Resistance: 1.0ohms
* Inductance: 11mH+/-20%(1KHz)

http://www.cncrouterparts.com/specs/...ta%20sheet.png


What type of problems can inductance lead too? I am unfamiliar with inductance to begin with.



Thanks a lot for your help,

Mike

[Jon.N.CNC]

I tried connecting the lead too the Y axis and still the same problem. so i believe that rules out driver error.

I am able to turn the ballscrew with my fingers to raise the axis. the stalls happen at random parts of travel, so the bearings seem to be rolling free.

Here is a video i just took, let me know what you think of this awful sound. https://youtu.be/MGEsGzhvtm4


Here are specs of the motor i ordered and my current motors. Is rated current the same as peak current? It kind of throws me off that the bigger motor says it takes less amps.

Manufacturer Part Number: 34HS46-5004D
* Motor Type: Bipolar Stepper
* Step Angle: 1.8 deg.
* Holding Torque: 8.5Nm(1204oz.in)
* Rated Current/phase: 5.0A
* Phase Resistance: 1.0ohms
* Inductance: 11mH+/-20%(1KHz)

http://www.cncrouterparts.com/specs/...ta%20sheet.png


What type of problems can inductance lead too? I am unfamiliar with inductance to begin with.



Thanks a lot for your help,

Mike

I had something similar happen, screw bearings seemed okay, was only when I removed them I found one had a very slight catch in it. Soaked them all in petrol before spraying with some silicone wd40 and they were good as new. No more stalling.

Just make sure you out the tapper bearing, if it has one, back the right way.

[MikeCaffey]

I had something similar happen, screw bearings seemed okay, was only when I removed them I found one had a very slight catch in it. Soaked them all in petrol before spraying with some silicone wd40 and they were good as new. No more stalling.

Just make sure you out the tapper bearing, if it has one, back the right way.

I will check that tomorrow thanks. I did have to repack the ballnut, so that has me a little worried too. It has been Good to learn on cheap parts first!

Thanks for the suggestion.

[Jon.N.CNC]

I will check that tomorrow thanks. I did have to repack the ballnut, so that has me a little worried too. It has been Good to learn on cheap parts first!

Thanks for the suggestion.

A ball in the no ball zone will do that too. Or too much torque in the bearing nut.

[awerby]

"I tried connecting the lead too the Y axis and still the same problem. so i believe that rules out driver error."

So you took the lead from the Z axis that was faulting, attached it to the Y axis, got the Y axis to fault, and you're still blaming the Z axis motor? To me, this seems to indicate a problem upstream from there - either the driver, a bad cable, a bad wiring connection etc. If the lead from the Z axis had driven the Y axis perfectly well, that would rule out a problem with the driver.

[RCaffin]

I ws about to say what Andrew just said.
Cheers
Roger