Please double check breaker size needed for CNC machine

[rt66electric]

MASAK CNC machine

name plate..

volts 230/460 3-phase
htz 60
spindle HP /15 cont 20/30min

139 / amps Largest motor
47.2 KVA power requirements
50/22 LA C.B. rating

I think something is lost from the japanese interpetation?

I used the 3p kva to amps formula

kva= V A sqrt3 / 1000
and came up with 56(60) amps for main breaker??

probably will be using 480v instead of 208.

Thank you in advance..

 

[petersonra]

MASAK CNC machine

name plate..

volts 230/460 3-phase
htz 60
spindle HP /15 cont 20/30min

139 / amps Largest motor
47.2 KVA power requirements
50/22 LA C.B. rating

I think something is lost from the japanese interpetation?

I used the 3p kva to amps formula

kva= V A sqrt3 / 1000
and came up with 56(60) amps for main breaker??

probably will be using 480v instead of 208.

Thank you in advance..

I don't know what you mean by 56(60).

If the total load is really 47 kVa, then the FLA is about 58 A at 480V, or double that at 240V.

I don't see how you can have a motor that has a flc that exceeds the total load of the machine.

Personally, I'd be inclined to feed it with a 100A circuit. That would give you plenty of juice for any auxiliary equipment that might be added along the way.

Or you could just call Masak service and ask them. They are supposed to be pretty good from what I have been told.

 

[Fulthrotl]

Personally, I'd be inclined to feed it with a 100A circuit. That would give you plenty of juice for any auxiliary equipment that might be added along the way.

yup. chip conveyors, chip augers, all sorts of extra things.

also, summertime changes things a bit. stuff gets hotter,
meaning controls and such, and more power is consumed.

i watched a 5 axis machine draw 15% more power at 2pm
than at 6 am. nothing different except the ambient temp.

 

[nollij]

I don't know what you mean by 56(60).

If the total load is really 47 kVa, then the FLA is about 58 A at 480V, or double that at 240V.

I don't see how you can have a motor that has a flc that exceeds the total load of the machine.

Personally, I'd be inclined to feed it with a 100A circuit. That would give you plenty of juice for any auxiliary equipment that might be added along the way.

Or you could just call Masak service and ask them. They are supposed to be pretty good from what I have been told.

Perhaps the manufacturer knows what the load will be when running at max feed rate and max spindle rate and has sufficiently oversized the motors for reliability.

It could also be that the spindle motor and axis motors may be DC and the voltage rating of the motor might be a bit different than what the input voltage to the machine is.

I don't suppose this manual has any sort of wiring diagram? Even smaller machines tend to have wiring diagrams in their manuals with replacement part catalog #s.