Standard vs Quiet splindle power question from a NewB

Hi there!

Appart from the noise, the need for additional PSU and PWM speed controler, what are the practical differences (torque, cut speed & depth etc…) between the 24v 300w standard spindle and the 48 volts 300w Quiet Spindle. And while we’re at it: what about the 400w 48v option… 25% more torque than the 300w?


A little info:

Thanks Nam37.

I have been viewing this chart before, unfortunately, it says nothing (as I can understand) about torque, if torque is the unit of measurement that is on purpose here. Sorry I’m no mechanical engineer to do my own calculations.

What I can calculate is that 24v 300w will take 12.5A while 48v will take 6.25A

But they are both providing 300w of power. How does it translates on an aluminum block?.. I guess they will perform equivalently, but I saw other documents from Inventables (avail as downloadable PDF on the quit spindle page) that I can’t truly decrypt.

That’s why I ask knowledgeful people!

I will post the PDFs here later, now i’n on the road will a mobile phone.

Thanks to all!

OK, I’m no electrical engineer either. I’m going to go out on a limb here, so someone please correct me if I’m wrong with this, but here’s how I understand things. Torque changes inversely with the RPM. As RPM’s go up, torque goes down, and vice versa. So for any of these variable speed spindles, the torque would be specific to the RPM that you choose to rate it it. The Dewalt 660 is fixed at 30,000 so that’s the only one where you’ll have a static torque rating. But since the VDC isn’t part of the formula, it shouldn’t affect the torque.

Here’s a formula… Torque = Watts * 9.554 / RPM

So for the 24VDC 300W spindle at max RPM, Torque = 300 * 9.554 / 14000 = .20472 Nm / 1.35582 = .15099 lb.ft.
And at low RPM, Torque = 300 * 9.554 / 2500 = 1.14648 Nm / 1.35582 = .84559 lb.ft.

For the 48VDC 300W spindle at max RPM, Torque = 300 * 9.554 / 12000 = .23885 Nm / 1.35582 = .17617
And at low RPM, Torque = 300 * 9.554 / 2500 = 1.14648 Nm / 1.35582 = .84559 lb.ft.

thanks Matt.

This really helps me understand the animal!

I have only some basic understanding that may or may not apply in a general way.

  • With many motors, lower voltage will reduce top power and RPM.

  • A motor rated for lower top RPM @ spec power and volts will have more torque than the same rated for higher RPM because it is wound or built to put more of the power into the torque rather than the RPM.

At least with most smaller motors used for RC type applications.

Technically, the 400w should be around a 1/3rd increase from 300w.

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I had one of the original spindles, from one of the first batches, but after that died I upgraded to the 300w Quietcut. If acoustics is a bigger factor to you than power, then the Quietcut is for you. There is a significant drop in noise level, and the noise quality is better, not as high pitched and ear piercing. Definitely improves the work environment and the neighbours will be happy too.