Max Load on Transformer Calculation

Discussion in 'The Projects Forum' started by Cdubbs, Jul 15, 2011.

  1. Cdubbs

    Thread Starter New Member

    Jul 15, 2011
    I have a dewatering field where I use multiple 5HP single phase 230V motors. On each power pole, I have a 25KVA transformer going from 4160V to 120/240V. My primary delivery is 25KV that gets transformed at the metering point from 25KV to 4160V and the transformer is rated for 250KVA. I was wondering what the max number of 5HP motors I could have in the system using the setup listed without blowing up the 250KVA transformer. If someone could post an equation and a solution to figure this out, that would be much appreciated!
  2. #12


    Nov 30, 2010
    Actual efficiency is a large part of this.
    25KVA/actual KVA of a motor = motors per pole
    Motors per pole times actual KVA per motor divided by actual efficiency of the pole transformer = KVA per pole.
    KVA per pole divided by actual efficiency of the 250KVA transformer = load on 25KV line.

    Not being a Glenn Campbell (lineman for the county), that's the best I can do.