electronic lead screw

[Briney Eye]

i got bit by a local supplier of steppers, 3 duds sitting here basically useless. The new business owners cant rebate me, but admit they were impossible to drive, & no longer sell them.
Reason is because the Inductive reactance, is way too hi, & the mechanical resonance was aweful to boot.
The Inter-winding capacitance was also hi.

The new ones from Stepperonline are 1/3 of the orig at XL~2,5 ohms.
XL=2pi x freq x L, so the higher the stepper rate, the greater the inductive reactance, or more simply, the impedance at that frequency.
Anything over 180 RPM at full step rate, & those ****ty motors clagged out.
The new ones driven at full step, (so non-sinusoidally driven), stall after 1500 rpm, a big difference. Thats, no mechanical load, No mid band resonance tuning, which evidenced itself at about 950 rpm, from memory.
Alos,
Sometimes a heavy steel disc (damper) is clamped onto the stepper shaft to dampen the resonance, the downside is the accel/decel rate needs to be tempered accordingly. It also helps if a heavy-ish steel plate is fixed securely to the steeper body to help dampen this resonance.
BTW, A rubber mount method should never be used!

Stepperonline is selling mostly Leadshine, I think. That's the logo on the motor that I bought from them, and I noticed that they explicitly say that their driver is designed in-house and built by Leadshine. I've got one of their CL57T drivers, but wound up using the HBS57 that I got from Banggood because it runs quieter and cooler. I tried tuning the CL57T and may try it again to get a better handle on what the different parameters do, but the HBS57 just worked without fiddling with it.

I tweak the step rate in my code to mitigate resonances and it has worked pretty well. It's been almost silent at lower rpm's, and only whines a little at higher speeds. We'll see what happens with the new ratios and motor.

I also just noticed that Stepperonline has a new CL57Y driver (in Hot Rod Red) with "a new generation of 32-bit DSP control technology" that I probably would have ordered with the motor if I'd noticed it sooner.

 

[GreatOldOne]

Is that a galvanised steel mounting plate the goodies are bolted to, GreatOldOne?

It was purchased from the local DIY shed. It didn’t specifically mention that is was galvanised, just 1mm thick and yay big. I needed something to mount all the goodies to, as the plastic box didn’t have a real backplane to speak of. Just some grooved ridges for screws. All the main parts bar the launchpad are fixed in place with rivnuts and M4 screws, the launchpad has some m3 plastic standoffs. The mounting plate is anchored in the box with M3 self taping cap heads.

 

[RJSakowski]

I got my hybrid stepper and driver in yesterday along with the Omron encoder. The stepper is from StepperOnline and is their 24HS40-5840-E1000 with 4.25 N-m holding torque, 24-48 volt, 6 amp. The question that I am facing is what is an appropriate power supply. StepperOnline recommended a 250W 36volt switching supply but that seems a little light to me.

 

[Briney Eye]

I got my hybrid stepper and driver in yesterday along with the Omron encoder. The stepper is from StepperOnline and is their 24HS40-5840-E1000 with 4.25 N-m holding torque, 24-48 volt, 6 amp. The question that I am facing is what is an appropriate power supply. StepperOnline recommended a 250W 36volt switching supply but that seems a little light to me.

I see that they list their 350W 48V supply with the motor, and I think that I would want the extra headroom. My 2Nm Nema 23 stepper setup seems to "behave" better with a 36V supply, but I don't know what will happen when I switch it to a 3.5Nm Nema 24 motor and a 350W supply.

 

[whitmore]

Is there a method or calculator online that can help estimate the feed screw HP requirements?

If you use the wrong drill on brass, the problem isn't feed pressure, it's feed TENSION as the drill
tries to dig in. So, feed pressure (like from the feed screw) will depend strongly on tool geometry,
and material being worked. Torque will be proportional to pressure, with some friction added.
If your tool is a grinding wheel, the expected applied pressure will be near zero.

It might be prudent to analyze the feed-motor power and adjust cut depth (rather than
hit the limit and stall, which could ruin a workpiece).

 

[Flyinfool]

36 volts at 6A equals 216 watts, so the 36V 250W PS would be adequate.
48V at 6A equals 288 watts, so a 48 V 350W will also get the job done.
To figure watts it is volts times amps equals watts.

48V will get more motor torque that 36V.

 

[Qtron]

Stepperonline is selling mostly Leadshine, I think. That's the logo on the motor that I bought from them, and I noticed that they explicitly say that their driver is designed in-house and built by Leadshine. I've got one of their CL57T drivers, but wound up using the HBS57 that I got from Banggood because it runs quieter and cooler. I tried tuning the CL57T and may try it again to get a better handle on what the different parameters do, but the HBS57 just worked without fiddling with it.

I tweak the step rate in my code to mitigate resonances and it has worked pretty well. It's been almost silent at lower rpm's, and only whines a little at higher speeds. We'll see what happens with the new ratios and motor.

I also just noticed that Stepperonline has a new CL57Y driver (in Hot Rod Red) with "a new generation of 32-bit DSP control technology" that I probably would have ordered with the motor if I'd noticed it sooner.

CL57Y sounds good but flaws may not show up for a while (if any). Will keep in mind, Thanks! Not sure what U mean by ''tweek the step rate in my code to mitigate..'' - normally the stepper is tuned in with the driver, which sometimes comes with a tuning software tool as per the CL57Y.
Does that mean, when U release the code, that users will have to tweek (if no software tool avail)? [technophobia is starting to show-eh!]
FYI, the pdf for their manual is a dud link: https://www.omc-stepperonline.com/download/CL57Y.pdf

 

[RJSakowski]

Thanks Briney, Flyinfool;

I wasn't certain as to whether the quoted current spec. was per winding or total current. In my past experience, it has been the latter. I also don't know what the relationship is between winding current and power supply draw. Additionally, my concern is the ability of a switching supply to handle current surges and back voltage spikes. I had read that linear supplies were preferred for that reason. When excess current is demanded from a linear supply, the voltage just drops. A switching supply will error out. Back voltages on a transformer/diode bridge/capacitor supply are absorbed by the capacitor. How does a switching supply handle them?

I'm leaning towards the 400W 48 volt supply. There is about 20% more available torque at speeds above 200RPM over a 36 volt supply. The 20% extra current capacity won't hurt either.

 

[homebrewed]

All power supplies, switcher or linear, have some capacitors across their outputs. Passive filtering is the way to go to ensure low output impedance at higher frequencies (which is a Good Thing for a PSU to possess). However, switchers may have smaller caps compared to linears. So what's wrong with adding your own capacitors to the switcher output? The current needed to charge them might cause the switcher to error out; but maybe not, because the charging current is directly related to how fast the switcher's output can ramp up: I = C*dv/dt, where dv/dt is the output ramp rate.

To handle large transient current demands the outboard caps have to be fairly large values, but certainly no larger than what a linear would have. And you still avoid the added size and weight of the linear's transformer.

Hanging caps on the output of a switcher should NOT cause it to become unstable, because all electronics have power supply bypass capacitors in them anyway. So that's not the issue, it's whether or not the supply will complain about the initial charging current.

 

[GreatOldOne]

It’s ALLLLLLLLIVE!

I’ve added a small 80mm fan to draw air in at the bottom. The blue light is a buck convector stepping down the 24v supply to 12v.

All the connectors are of the locking type. I had to get a larger, 16mm connector for the servo encoder, as the cable diameter was to great for the shell. I’ve added some vents to the top of the case to allow hot air out. 3D printed grills from thingiverse, as was the fan grill on the front.

Flashed the board with James’s firmware, and fingers crossed:

It works! Yay. Happy dance ensue.