Please explain this mill electrical rating

I do not really think that I understand the full implication of this rating from a milling machine manual. Could someone please clarify.

"200,220,230 Volt, 60/hz, 3 phase input and 3.7 Kva output"

OK, obviously three possible input voltages but I do not usually see the voltages listed so close together normally.
Frequency and phases I understand.

The Kva output. This seems to imply the current required by the mill will be something around 17 amps under certain conditions. However, this is the output rating, would this include ALL current users or just the spindle (eg the work being done)? Would any calculation using the Kva output need to be corrected to provide the working input current to account for such items as the control system?

Sorry but I have never seen power supply requirements expressed like this before. If it helps, the mill is Japanese. Basically what I need to know is the input current of this machine so that I can use it to plan the power supply required.

Thanks, Brian

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The current draw will be about 12 amps. Current is power/(phase-phase voltage * square root of 3 * power factor)

The 'output power' terminology seems to have crept into indicate what logical mided people would regard as the 'input power', so unless the spindle motor is specifically 3.7kW/5hp, then assume that it's the input power. Assume that the power factor is about 0.8, The electronics will be a trivial part of the total load. Power factor could be a lot higher for a DC/servo spindle, but it won't mean a lot in the grand scheme of things.

Thanks Mark,

The power specifications I stated are as supplied by the present owner of the machine from his manual. I will query him because I suspect a typo. The spec. is for a milling machine with a 15HP spindle motor so the current draw has to be somewhere around 40 amps just for the spindle.

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15 hp is 11.1 Kw, 42-48ish amps 220-200(edit had order wrong) is correct


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Yep,
Something is not making sense here.

As Ripperj calculated the motor should be pulling 40+ amps and the owner said he had been making steel molds using 1" cutting tools so I imagine he was driving it fairly hard. The seller is the original owner and the machine is in the position where it was originally installed (although the shop electrics had an upgrade at some point). I saw the toolholders and the 1" is correct. So, we have the load of a 15HP spindle motor and the load of 3 DC servos to consider but the machine has been running for years with no apparent problem from a 40 amp 3-phase breaker.

I will try one more visit to read the manuals myself and check the ID plates on the spindle motor in case this machine was supplied with a lower power spindle option. (Shizuoka B5V).

Thanks Guys.