How to calculate cable sizes in sq.mm. with using motor KW?
Any formula there?
Answers were Sorted based on User's Feedback
Answer / khalander mulla
normally for copper cable 2.5amps 1sq mm
for alluminium cable 1.5 amps for 1sqmm
Is This Answer Correct ? | 432 Yes | 143 No |
First of all you need to verified full load current of motor,
How can you calculate:
Ex: 1 Motor - 20HP 3ph. 415V 50Hz, 80% efficiency
Cal: A= HPx746/(sqrt3xVoltxPFxefficiency)
=20x746/1.732x415x0.8x0.8
=32.43Amp.
We all know that a motor has 1.5 times starting current,
Then 32.43x1.5 = 48.65Amp
Now you can see in the current currying capacity of cable from manufacturer cable's list.
3.5 x 35 sqmm xlpe cable is sufficient for full load.
Is This Answer Correct ? | 347 Yes | 171 No |
Answer / bethi arun reddy
normally for copper cable 2.5amps 1sq mm
for aluminium cable 1.5 amps for 1sq mm
That is the answer.......
Is This Answer Correct ? | 149 Yes | 77 No |
Answer / abdool
3pahse power is P(in KiloWatt)=I.V.PF.(root 3).....
I=1.74 x P(KW)
EXAMPLE:
so, assume 3ph 400V 15KW motor, In=1.74x15=26.1 A,
& 15KW=20HP.....so 2xIn=Breaker rating= 52.2A
...choose 63A MCB
Cable size normally 20-25% higher than breaker to avoid
cable heat/burn accident in overcurrent fault. so, 1.25xIn=
62.64A so choose 80A Cable rating of 25mm2.
Is This Answer Correct ? | 101 Yes | 66 No |
Answer / parveen
We must consider numerous factors to calculate the exact
safe size of the cables for a particular load.
Please let us know whether the cable is to be laid in
ground or it will be overhead or any other way.
Secondly, you want an aluminium cable or copper cable?
Thirdly, the load is single phase or 3-phase?
Moreover, the motor is induction motor or any other type?
because we have to consider harmonics also.
For e.g for a 3-phase load of 80kw, the aluminium cable to
be laid inside the ground must be 150 sq.mm for perfectly
safe operation.
Is This Answer Correct ? | 41 Yes | 14 No |
Answer / a.bala
Hameent your statment is applicable for only small cable
size ( Up to 16 sq mm ) Please reff any one catalouge
Is This Answer Correct ? | 50 Yes | 32 No |
Answer / rana farrukh anwsr
First of all we will chk rated amp mentioned on motor then will check from chart abt cable sq mom size
Is This Answer Correct ? | 23 Yes | 9 No |
Answer / ramkashyap
For Cable Current Capacity = 4X Size of Cable in Sq.mm, Ex. For 2.5 Sq.mm = 4×2.5 = 9 Amp.
Is This Answer Correct ? | 48 Yes | 38 No |
Answer / s d chilatre
required copper wire in kg for rewinding Ind. motor for various rating
Is This Answer Correct ? | 10 Yes | 3 No |
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