8x30 mill, motor size

[slow-poke]

I plan to replace the original single phase 1.5HP motor on this mill with a three phase motor and VFD. I did this upgrade on my previous mill and it was well worth the minimal effort and cost. For my old mill I used an eBay special 1.5HP inverter rated motor and it has worked flawlessly. I never mess with the pulleys and belts, the range of speeds with just the knob is perfectly adequate for everything I do. The only shortcoming is power/torque when using a really large drill bit, and very slow speed And not bothering to move the belt to a better ratio.

I suppose I could up the HP a bit this time perhaps to 2HP

Thoughts?

 

[Susquatch]

Although I've done it myself and in fact I'm doing it again right now, I'm always leary of doing it. The rest of the machine isn't sized for the additional power.

That said, mills almost never use or see the additional power. Especially if you program in a nice smooth ramp up to target RPM. At that point it just becomes a heavier motor.

The spindle sees the load that the cutter sees from the input torque that the pulley reduction feeds it. So a bigger slower motor doesn't really change that unless you feed it a bigger load.

That's my first take anyway. On that basis, I say go ahead and do it. But don't load it up more than you would have previously by changing pullies.

Nonetheless, it's an interesting question with many nuances. So I'll think about it a bit more and then come back and add to this thread if I change my mind.