3 phase loads 1

[TheDemps]

I am intending to connect 9 2kw metal halide lights so that they are balanced over the 3 phases. The supply voltage is 400v between phases. This will mean that the load is balanced with 3 lights connected in paralell across each phase. This will bean that there is 6kw connected between phases. I want to know how to calculate the current taken from each phase of the supply. I do not know the power factor of the lights. Any help would be greatly appreciated.
Thanks in advance.

 

[rbulsara]

Its simple.

If the load is evenly divided between the three phases, the total load is 18kW (3*6kW).

For a balanced three phase load, Line Current I= (18kW/p.f.)/[(SQRT (3))*400] in each line.

where kw/p.f.= kvA.

Or you can say voltage per phase is 400/sqrt 3 =230V

Current for each phase = kva per phase/voltage per phase
=(6kW/p.f.)/230. Either shall result in the same current value.

 

[TheDemps]

Thanks rbulsara, that's exactly what I was looking for

 

[rbulsara]

One correction:

I forgot the factor of 1000. Multiply kVA*1000 to get VA.

(or use voltages in kV).

 

[jbartos]

Suggestion: The current may need to be increased a little bit since there will probably be ballasts that will increase the 2kW to some higher value depending on which type of ballast is applied.

 

[TheDemps]

Thanks jbartos,
I got the power factor rating of the ballast from the lighting manufacturer and I have sorter out the problem.
Thanks to all for your helpful replies.