Yeah. there was a good post made to reddit on power considerations recently which I cribbed at: Shapeoko CNC Router, Rigid, Accurate, Reliable, and Affordable
2.2kw is about 3 HP. 1 HP is 745W, 745*3 = 2235W (which isn’t far from 2.2 * 1000). W/V=A, therefore 2235W/110V = 20.31 A, and thats assuming no losses in your transformer/inverter, voltage drop in your household wiring or other equipment running on the same circuit. Most 110V outlets are 15A though there are some rated for 20A. The reason you don’t see any inverters that turn 110V power into 220/3ph power above a certain HP/kW rating is that there simply isn’t enough amperage on the circuit to drive them
So it looks like there are three possible upper power levels for an electric motor in the U.S. (if one can dedicate a circuit to it):
- 110V @ 15A
- 110V @ 20A (requires a suitable circuit and plug)
- 220V @ 20A — tap into the stove or dryer plug
(it’s too early to do math)
The next question is, what is the optimal motor size/diameter for each of those power ratings, and after that, what is the largest diameter tool which would make sense, and what speed rates would generate suitable chiploads w/in the range of feed rates the machine is capable of, which results in the corollary: Are there any such ratings which are not addressed in the market?
The Kress 800-FME seems to indicate there might be some lacunae: https://mctinfo.net/kress-800-fme
I know I’d give a lot for a spindle which:
- was 110 AC @ 15 amps
- quiet (unfortunately the Kress is noted as loud)
- narrower than 65mm (want to reduce lever effects)
- used an ER-20 collet, or had a 1/2" collet option — the Makita having a 3/8" collet option makes this seem achievable
- had a brushless motor — been considering buying the 18v Makita trim router and just wiring it to a suitable power supply — weird to me that the Kress uses brushes
- air cooled