# Current in Secondary Windings of Toroidal Transformer

I am trying to design a toroidal transformer with multiple secondary coils. The core of the transformer is rated at 2500VA. Each of the secondaries powers a dc servo motor wich is subjected to a highly dynamic load.

There are 3 motors that require 24v at 3-30 amps depending on the load, and 2 motors that require 15 volts at 1-7 amps depending on the load.

If I were to make a secondary winding for each of the motors, how would I calculate the current in each winding?

I know the formula for an ideal transformer is: Vs/Vp=Ns/Np=IP/Is but if the 3 24v motors are simultaneously drawing huge currents, does that mean the other motors will have too much current or is "Is" in that formula just the maximum available current and the motor will draw what it needs?

is "Is" in that formula just the maximum available current and the motor will draw what it needs?

The motors will draw what they need - just because you take 30 amps in one winding it doesn't mean other similar windings are forced to deliver 30 amps.

You will see some "regulation" issues but these may not be significant. If you draw 2160 VA for the three big motors you will see the 15 volt secondaries lower there supply maybe 5 or 10%. It's inevitable because the primary winding isn't perfect and it has losses - you take current from a secondary and this gets transferred to a current on the primary and, leakage inductance and copper losses means you lose some ability to keep delivering voltage perfectly to each secondary.