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Load Calculations for 400v single phase floodlighting

seansasta
Hi Folks

Could someone please advise if my calculations below are correct? I'm calculating total load on a 3 phase 400v system for a floodlighting load consisting of 36 No 400v single phase ("2-phase") Luminaires. I thought my calc's were correct then I read some other posts online which used 3 phase formula (as if the stated lighting load was 3 phase) which left me with enough doubt in my calc's to seek some expert advice from you guys...

Supply: 3ph/400V

Load: 36No Philips OPTIVISION MVP507 1xMHN-LA2000W/400V/842 WB/60, with a stated load of 2123 W each, equally divided across the 3 phases, (I have assumed a Pf of 0.9 for the ballasts).

I have treated these as single phase loads, therefore...

I total = (2123*36)/(400*0.9) = 212.3A; divided equally across 3 phases = 71 A (70.77) line current

Therefore, (Assuming I used the correct calculations above) total 3 phase power in KW = ((400*1.732*0.9*71)/1000) = 44.27 KW


Any confirmations or corrections would be greatly appreciated.


Thanks

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  • 0
    400 volt lights have two advantages if compared to 230 volt fittings.

    Firstly for high wattage lamps, they are simpler and cheaper to manufacture as large discharge lamps tend to have an arc voltage too high for operation via a series choke from 230 volt circuits.

    Secondly, 400 volt lights may be connected between phase and neutral on a 4 wire 400/690 volt system, use of this higher voltage system considerably reduces voltage drop and cable sizes.


    For operation from a UK standard 230/400 volt system, the advantages are confined to lower price/better availability of the light fittings, and a slightly greater efficiency since a 400 volt 2000 watt discharge lamp will have a slightly greater output than a 230 volt 2000 watt lamp of similar design.


    If the total loading is known to be say 76.5 Kw, balanced between 3 phases, of a 230/400 volt system then the line current has GOT to be the same* no matter if the fittings are 230 volt or 400 volt. "you can not miniaturise the watt"


    *There may be minor differences if the efficiency or power factor varies, or due to manufacturing tolerances, or rounding of figures in calculation.
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  • 0
    400 volt lights have two advantages if compared to 230 volt fittings.

    Firstly for high wattage lamps, they are simpler and cheaper to manufacture as large discharge lamps tend to have an arc voltage too high for operation via a series choke from 230 volt circuits.

    Secondly, 400 volt lights may be connected between phase and neutral on a 4 wire 400/690 volt system, use of this higher voltage system considerably reduces voltage drop and cable sizes.


    For operation from a UK standard 230/400 volt system, the advantages are confined to lower price/better availability of the light fittings, and a slightly greater efficiency since a 400 volt 2000 watt discharge lamp will have a slightly greater output than a 230 volt 2000 watt lamp of similar design.


    If the total loading is known to be say 76.5 Kw, balanced between 3 phases, of a 230/400 volt system then the line current has GOT to be the same* no matter if the fittings are 230 volt or 400 volt. "you can not miniaturise the watt"


    *There may be minor differences if the efficiency or power factor varies, or due to manufacturing tolerances, or rounding of figures in calculation.
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