Hello all! New member on the forum here but long time lurker. I’ve had a Nomad 883 Pro for a few years. Back when I first got it, the spindle drive board was toast. I swapped it with a BLDC-8015A driver and swapped in the largest Nema 17 BLDC motor I could get, the uber powerful 78 watt one!
Well, I have a larger project I need to mill out that is going to require a lot of material removal, and the spindle motor keeps me from attacking this as it is so sensitive to any excessive load its not worth the risk of a crash because Fusion did something stupid I didn’t anticipate. So, after a little searching I found this thread: The beginnings of a near drop-in Nomad Pro 30kRPM spindle upgrade
So I decided to do something similar. Basically, I’ve strapped that same motor to my machine with a similar bracket and wired it into the BLDC-8015A and added a beefy adjustable power supply.
So, the problem I’m currently running into is the BLDC-8015A has two modes it can operate in, one is with a potentiometer that can regulate speed, and the other is with PWM. If I set it to the potentiometer, I can get full RPM. Its ungodly fast. And the power… Oh the power…
But if I set it to PWM and set the spindle speed to 10,000rpm in a program (no changes to GRBL yet for the max RPM and junk, all stock software/firmware wise) then its running at probably near stock speeds. The signal there should be 0-5v analog OR a 1Khz 5v PWM signal. I’d imagine the motion control board outputs a PWM signal, but does anyone know the carrier frequency and the max voltage? I am willing to go as far as to build a translator for the signal to get the PWM to work, but if I do that I may just swap to a VESC and use a ESP2866 to accept the signal from the mill and translate it to whatever the VESC wants. I don’t have access to a scope anymore so I can’t check it myself. Anyone willing to probe the output or have done it in the past?
It’ll take a few days to see how this bugger runs though… I’m waiting on parts. Specifically a new motion control board… I inadvertently killed it troubleshooting because I forgot to disconnect the PWM output and touched the pin with 5v. It didn’t like that. So now it doesn’t chooch at all, but a new board is on order.
Well, I contacted support while giving them information on the machine for the replacement motion controller. The PWM carrier frequency is 1Khz in case anyone else needs this information.
The BLDC-8015 driver sucks, so I can’t suggest it at all. No speed fidelity at all with a 14 pole motor… I’ll be making a pwm to pmm converter and throwing a VESC on there to drive it with some actual speed fidelity so I can cut steel and have better drilling, but right now for cutting aluminum it RIPS! I’ve got some 5mm cutters on the way and I can’t wait to see what the MRR will be like with those. I think this has a lot more overhead in terms of power, so I think I can swing a larger diameter endmill with a deeper DOC and maintain a 50% stepover.
yep, bone stock. Even has the original bearings in it, though I need to change them out as I can feel one is going bad. Its running at 16k rpm so it should be fine. 24k rpm is easily doable with a pulley and belt change but I don’t dare do that until the bearings are replaced. I may also do what @TonyDangerCoiro did and build a spindle with a 10mm shaft and tapered roller bearings.
I have video of it that I need to upload. Its wild how fast the chips build up now. I can’t believe how much this has transformed the machine from a metal scratcher to a chip flinger. Having the ability to rough in a large 6x6x1" material in 30 min or less is going to drastically change the projects I do on this thing. I believe the 8mm spindle is the current bottleneck and I have what may be a simple 10mm shaft upgrade. I ordered parts and they’ll be here in the middle of June. If it works, that makes this whole project a bolt-in affair that gives you over 1/2hp, maybe closer to 3/4hp in a Nomad. My peak wattage measured at the plug was 680w. With the motor off it consumes 12w. That poor little timing belt LOL!
With a vesc you could slap an encoder on there and get real time spindle readings. Could be interesting for ramping up/down power through a cut. Though if you’re going full power all the time I suppose that doesn’t matter much
Still, for like $30 it might be worth knowing exactly how hard your spindle can push.
