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How you calculating the current for a 2.5 Sqmm cable.
A 30 Hp 3 phase AC motor of power what size of cable is
used for this motor.

Answers were Sorted based on User's Feedback

How you calculating the current for a 2.5 Sqmm cable. A 30 Hp 3 phase AC motor of power what size o..

the answer is wrong we can calculate by usbing this formula
W = 1.732*V * I Cos (phi)
30*746 = 415 * I * 0.8*1.732
I=36.2 AMP

 Is This Answer Correct ? 24 Yes 6 No

How you calculating the current for a 2.5 Sqmm cable. A 30 Hp 3 phase AC motor of power what size o..

deciding a cable has to consider following parameters also,
1. Safety factor of the cable (margin for starting current
say 1.25 in numerator side)
2. Deterioration / Degradation factor (say 0.8 in
denominator)
calculate the current of the motor by considering running
pf (power factor) say 0.8
as motor gives real power
e.g.
W = V * I Cos (phi)
30*746 = 415 * I * 0.8
I = 30 * 746 / (415*0.8)
I = 67.41 Amp,
Thus Current considered for cable (Icb) = 67.41*1.25/0.8
Icb = 105.3 Amps.
Select from the catalogue suitable copper cable for this
motor. Dont forget to consider the voltage drop per meter,
the total voltage drop shall not be more that + - 5%.

 Is This Answer Correct ? 15 Yes 9 No

How you calculating the current for a 2.5 Sqmm cable. A 30 Hp 3 phase AC motor of power what size o..

For calculating the current rating of a 30 Hp 3 phase motor can be written as
power = sq root(3)* VL*IL*cos (phi)--------(1)
where 'VL' is line voltage, 'IL' - line current and cos phi- power factor

OR 3 EP*IP*cos(phi)
as the voltage fed is from three phase system.
Power input of 30 Hp motor = 30*746/(efiiciency*cos phi) watts
from the formula (1) and taking efficiency as 0.9,
Line current 'IL' = 30*746/(1.732*415*0.9*0.83)
= 41.68 Amps

 Is This Answer Correct ? 6 Yes 3 No

How you calculating the current for a 2.5 Sqmm cable. A 30 Hp 3 phase AC motor of power what size o..

10sqmm cooper

 Is This Answer Correct ? 1 Yes 1 No

How you calculating the current for a 2.5 Sqmm cable. A 30 Hp 3 phase AC motor of power what size o..

As per thumb rule
Power Sq root 3=1.732
Voltage =415
PF=0.8
Cos=0.85

1.732*415*0.8*0.85=488.77

30HP*746W=22380/488.77=45.79 Amp

 Is This Answer Correct ? 0 Yes 0 No

How you calculating the current for a 2.5 Sqmm cable. A 30 Hp 3 phase AC motor of power what size o..

If its a 2.5Sq.mm Aluminium cable then it can take load
current upto 3Amps and if its Copper cable then it can take

And for a 30HP motor the cable size shall be 3.5Core X
16sq.mm Aluminium or 3.5Core X 6sq.mm Copper cable.

 Is This Answer Correct ? 17 Yes 23 No

How you calculating the current for a 2.5 Sqmm cable. A 30 Hp 3 phase AC motor of power what size o..

we are measure through SWG ( standard wire guage
it measure the crossection of wire
2.5sqmm

 Is This Answer Correct ? 13 Yes 20 No

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