An assignment question

[scooby]

please can some one tell me the formular for these questions
what is the design current for
Alight circuit having 5 twin 70 watt luminaires supplied at 230 volts each having a p.f. of 0.85

A 230volt a.c. motor having a p.f. of 0.7 rated at 840watts

And two tungsten halogen floodlights controlled by one switch from a 230volt circuit

 

[plugwash]

please can some one tell me the formular for these questions
what is the design current for
Alight circuit having 5 twin 70 watt luminaires supplied at 230 volts each having a p.f. of 0.85

is that 70 watts per tube or 70 watts per fitting?

A 230volt a.c. motor having a p.f. of 0.7 rated at 840watts

840/0.7/230 ~= 5.2173913043478260869565217391304amps

And two tungsten halogen floodlights controlled by one switch from a 230volt circuit

assuming they are 500W halogens and thier power factor can be assumed to be 1
500*2/230 ~= 4.3478260869565217391304347826087

 

[scooby]

first question i am guessing it is 70watts per fitting so should this be
70*5/0.85/230=?
thankyou for your help

 

[ban-all-sheds]

70*5/0.85/230=1.7156862745 (mine is not as big as plug's...)

 

[Big_Spark]

please can some one tell me the formular for these questions
what is the design current for
Alight circuit having 5 twin 70 watt luminaires supplied at 230 volts each having a p.f. of 0.85

A 230volt a.c. motor having a p.f. of 0.7 rated at 840watts

And two tungsten halogen floodlights controlled by one switch from a 230volt circuit

(70*5) = 350 / 0.85 = 411.7 / 230 = 1.79A

840 / 0.7 = 1200 / 230 = 5.21A

What rating are the lamps, 75, 100, 120, 150 200, 250, 300, 500w or larger??