[DDM]

Hey everyone, I was looking at getting a xylotex board with either the 269 or the 425oz steppers and I was wondering what other users were getting for speed. The 425's are going to be slower of couse but how much slower? I've calculated that the 269s on a 24v are max 600-700 RPM. I would imagine that the 425's are around 400 RPM max on a 24V supply. Any input would be appreciated

Carl

[ger21]

With the 425oz motors, use screws with fewer turns per inch to keep the motors rpm's lower where they have more torque.

[Ed_R]

I realize this is an old thread, but I'm hoping that you can lend an opinion on using the 425-ounce motors with Acme 10 TPI thread. I'm thinking I'll get a reliable strong accurate 70 or so IPM. That's fine with me.
I'm upgrading from 116 ounce motors to the 425, using the same controller, and upgrading to dumpstercnc's anti-backlash nuts. I was able to take care of all issues on the original set up except for backlash and step loss due to those silly 116 ounce motors being too weak to handle much. They were also running at 3.44 Vref volts, Jeff suggests I run at 3.35 for teh 425-ounce inchers.
So whatcha think, Ger the Guru?

[ger21]

Imo, for a router, I'd use between 2 and 4 turns per inch screws. 1/2-8 2 start is probably the cheapest in that range, and you can get nuts from Dumpster for that size.

[Ed_R]

Figures. I'm running single-sstart 1/2-10.

I couldn't tell the difference between two-start and single-start. Never even heard of it before.
Bear in mind, I'm not travelling huge distances, I'm only going 24 inches , 18 inches, and 6 inches. Make a difference?

[ger21]

Should work fine, but if you want to go faster, switch screws.

[Ed_R]

I will probably buy some different screws at a later date. But I might just buy a bigger machine anyway.

[Jason Marsha]

I noticed the xylotex board supplies 2.5 amps, while the 497 oz/inch motor requires 3.0A, what torque loss should I expect if I use these motors.

Jason

[ger21]

You'll get roughly 2.5/3= 83% of the 497oz-in. Keep in mind this is holding torque, before the motors start spinning.

[Sanghera]

What does that mean when the motors do start spinning?

[Stepper Monkey]

What does that mean when the motors do start spinning?

Fast drop-off in torque, more rotor inertia and vibration, slower top speed, less smoothness, general loss of performance. The big number does sound very impressive, but let's face it, most people using xylotex drivers who get 497 oz. motors don't usually get them for when the machine is actually spinning, in the same way most people don't buy sports cars for the way they actually drive.

If you really need the best performance using the Xylotex, get motors better matched to the driver and your machine - even though that will likely be a lower number.
If you really need 497 oz./in., then get bigger drivers! Given your setup, in the end either one of those options is probably better and easier than new screws anyway.