Star Delta Motor Cable Calculation

[Eng_Omar]

Dear Experts,

I am used Ecodial 4.9.7 INT to calculate the requirements of the cable for the star delta 90KW motor and the distance for cable 20m, and i got the result as shown in the attached picture below.

my question is that result  ph : 1x70 mm CU represents the cables should i extend from main and delta contactors to the motor ? or i have to extend 1x35 mm Cu from the main and delta contactors to the motor ? .

Best Regards

[Karthikeyan1]

Hi Omar,

Thank you for the question.

As per your cable results in the attached screenshot, the calculated cable Cross-sectional area is Ph : 1X 70sq.mm and PE : 1X35sq.mm. This means, Ph- Phase conductor Cross-Sectional area is 1 run of 70 sq.mm cable and PE- Earthing conductor Cross-Sectional area is 1 run of 35sq.mm cable. 

So both the Phase and Earthing conductor of specified Cross-sectional area needs to be extended from main and delta contactor to the motor. 

Thanks & Regards,

Ecodial Expert Community

[Eng_Omar]

Hi Karthikeyan,

Thank you very much for your reply .

The thing that made me confusing that when i changed the motor control from star delta to direct the result of cable-stay same (please see attached picture ) .

As you know there are two cables in star delta that connect with both sides of the motor (the first cable comes from the main contactor and the second come from the delta contactor) , kindly can you explain to me how can i calculate the area of those cables by Ecodial ?

Best Regards

[Karthikeyan1]

Hi Omar,

Cable calculation on Ecodial is based on the full load current, voltage drop and certain other inputs. Not based on the starter type. If the full load current changes, then only the cable Cross-Sectional area will change. 

At present in Ecodial we cannot able size the different contactor cables on the Motor load. As a workaround, you can use the same Cross-sectional area of cable for both Main as well as the Delta contactor. 

Thanks & Regards,

Ecodial Expert Team