Volt Drop Calculation

grousedogtom

Quick question , i need to run two single phase motors 1 a 3 horse power and one a 1 horse power the ESB meter/consumer unit is 70 to 75 meters away, i used an online volt drop calculator and 4square cable was recommended. Is this a little on the light side or is it sufficient.
Many thanks

M cebee

sometimes what they do for motors is use 125%FLA for the 'design current'

are these starting simultaneously or on the same cable?what's the story?4sq seems light anyhow

grousedogtom

not starting together, 1 horse power will start first and then 3 horse power starting second.

M cebee

6 will do according to my calcs then-for the 2

4 is too small

Bruthal

6 square will work, but i think your looking at 10 square for that run, the output of the motors is 3kw when on together, and probably 4kw electrical load input to them.

What are the motors driving or powering?

M cebee

check for excessive VD on the supply as well(ESBN)-always a good idea before you start

M cebee

robbie7730 wrote: »

6 square will work, but i think your looking at 10 square for that run, the output of the motors is 3kw when on together, and probably 4kw electrical load input to them.

What are the motors driving or powering?

oops my bad robbie -i didn't convert the ouput to input:)

you're right he may need to go higher

i'll do it again

M cebee

i make it a 10 now-playing it safe as they say

Bruthal

I remember putting in a 60 meter temporary 2.5 to test a machine in a workshop, it was a wood planing machine, it had a heavy cutting head on it and took eternity to run up to speed, then when the proper 10 square went in the difference was unbelievable during the startup. It was tripping overload and all with the 2.5

Bruthal

The 4 square is certainly too small anyway.

grousedogtom

motors are driving augars in a livestock meal bin