I've just been playing with my latest toy, I need to make some decisions about the electrics before finally putting it in place where it will be less accessible. It has a 10hp motor, though it left the factory with one nearer 20hp with an electromechanical variator-type drive but that has all gone.
10hp will be more than enough for me! It has a continuously-running motor with clutches . I can start it OK with my 10hp-ish (Andrew, did you work out an 'official' rating for it?) phase converter (with 10hp idler motor). It struggles though when engaging the clutch for speeds around 1000 rpm and up, much above 1000 and it'll trip the supply breaker for the converter. What it would be helpful to know is, would running the motor via an inverter (fed from the Converter) ease the pain? I feel that it might, as the phases the motor 'sees' will then be properly balanced. I suppose another ploy might be, if high speeds are needed, to engage the clutch with the speed turned down on the inverter and then bring the speed up, that ought to help a bit. There's a wattmeter on the machine, which uses a current transformer in one phase and a 'mystery box' to make an artificial neutral. It's showing a peak of about 10kW when I engage the clutch at 1000 rpm with just the chuck, no work in the machine. Is that likely to be bothered by use in conjunction with an inverter? I envisage having the inverter 'last', ie connected direct to the motor and supplied via the original control gear and wattmeter.Thanks Tim