I wouldn't worry about it. Set the drives to 1/8 microstep, and see if it's better. That's where you should be running them anyway.
Hi,
I just started on my journey in the subtractive CNC world and ordered some parts to make a cnc machine. I've built a 3D printer from a kit so I'm not completely new to the mechanics and gcode etc. I also like to dabble in electronics in my spare time.
I've ordered 3 NEMA 23 stepper motors from Aliexpress (yeah I know), and one of the 3 stepper motors is about twice as loud when turning. I'd like your opinion wether I should return the motor and ask for a replacement or that it's just fine. I don't want any problems with bearings etc. Maybe it's just that this motor has stronger permanent magnets or something?
The motor type is 23HS2430B 425oz-in 3Nm 3A 1.8 degree per step from RATTM motors.
The drivers I'm using are FMD2740C set to 1/2 step (full step is not selectable with these drivers, I might try to mod them if necessary). The drivers are powered by a 36V 11A psu.
I've tried swapping the driver but it really is the same motor that makes about 3dB more noise. If this isn't a concern other than the annoyance of noise, I'll just keep it and maybe replace it later.
All 3 motors weigh the same, so I don't think it's a different motor altogether. The DC resistance of all three motors are the same too, about 0.8 per coil, though the datasheet says 1.6 ohms, but I assume the values of both coils are added?
The induction I didn't check yet, but if needed I'll try to determine that as well. I'm planning on hooking up my oscilloscope to see if the waveform pattern is different, if I find a safe way to connect it. I probably need an isolation transformer but I'm not entirely sure.
Here a video with audio recording using an external mike:
https://youtu.be/5_J6OzGV4Wo
I would really appreciate your opinion, thanks!
Imqqmi
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I wouldn't worry about it. Set the drives to 1/8 microstep, and see if it's better. That's where you should be running them anyway.
Gerry
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(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Disconnect the motor and hold it on your hand and spin the shaft several times around. It should have a distinct detent feel as you move it the 360. The motor should not make any mechanical sounds or you should not feel any binding anywhere in the full rotation. The alignment of the rotor in a stepper motor is critical . There are only a few thousands of clearance between the rotor and stator "poles" . Dropping a motor or it taking a hit in shipping could have shifted the alignment. Never take a motor completely apart. its really hard to get them aligned front to back again. While the sound may not be a problem it could also point to something that could be in the future. We go thorough 1000's of motors a year and our QC dept will not pass a motor in final system test if it does not sound right.
Test them with microstepping on and if its still noisy consider buying another motor. It may be almost as cheap as paying the return shipping and waiting for weeks.