Circuit Braker & Contatcor selection

I have motor for example it's power 28kw (220/380 v , 83/48 A ,f=60), I need the way to calculate the circuit barker and contractor to this motor.

Thanks

shrakrhussain said:

I have motor for example it's power 28kw (220/380 v , 83/48 A ,f=60), I need the way to calculate the circuit barker and contractor to this motor.

Thanks

Click to expand...

What make contactor and circuit breaker?
what type of starting?
220V or 380V ??

FIRST step decide on what line voltage to starter is.
Then you must know ambient operating temperature to select wire insulation class. Now you can start picking what size conductor you need.
THEN all else Depends on what your starting method is.
IF VFD then you can size VFD based on full load current. Supply line can be sized for recommendation in VFD manual.

IF a contactor type starter bit more complicated.
Line conductor from overcurrent device at source is sized based on starting current or locked rotor amps. COnductor from starter to motor is based on full load amps.

IN ALL CASES a volt drop calculation should be done based on current for that conductor and the length. Wire size should be increased to ensure volt drop is less than 5%.

DO NOT SKIMP on wire size or component size - it is always better to have equipment with a little more capacity - last a lot longer.

I realize you are not in USA but USA NFPA NEC has a set of good guidelines. You should have enough information from a good electrician handbook or motor control book to do this.

There is always a catalogue for every company that has the ciruit breaker you want to use and the contactor.

Though the way written in the past reply is the correct one.

i am working in saudi arabia... you are welcome for help if needed.

Regards

what products are available to you where you are?