CLICK HERE TO GET THE INPUT FILE: RaleInput_307b

Drainage Choke between 2 parallel connected rectifiers 2x(24Vdc,500Adc) at 50Hz
to support good DC current distribution and limit 150Hz current harmonic

This choke has 2 windings with the center tap. Through these windings flow 2 currents:
⦁ the load dc current I=+500Adc and
⦁ the 150Hz current I3<=50A

The total ampere turns of the current I=+500A (marked by sign “+”) in the core window are equal 0 and the core is not magnetized by this current. The 150Hz rectifier voltage harmonics U3 drive the magnetizing ampere turns 2*W*I3*1.41, where W are the turns only of one winding (between the choke terminals and the center tap) and I3 the 150Hz current harmonic.

In order to use the Small Chokes Program, you need to know:

⦁ The inductance L of both ,in series connected windings W, at the peak current value I3peak=1.41*50=70.5A. Note that the role of the inductance L is to limit the 150Hzcurrent I3.

U3=Udc/8/1.41=2V and L=U3/I3/3/(2*pi*50)=42.5uH, where

Udc=24Vdc

⦁ The current I=+500Adc

Input : 
Open the input file RaleInput_307b.DK1

The most important parameters are:
⦁ L=>=42uH at 70A and the induction=1.42T
⦁ Cu Foil with 8 gaps per gap, which will be set to 0 in the test mode
⦁ Temperature rise 60°K at Ta=40°C
⦁ Steel M400
⦁ Core assembly=1 without the gap fixing plates (stacking factor=1) and the cooling channels

The Small Choke Program calculates the inductance L as follows:
L = Ls + Lfe*Lgap/(Lfe + Lgap)
Where:
-Ls => Leaking inductance
– Lfe => core inductance, when the gap =0
Lgap => gap inductance, when the core permeability is very high
Normally Ls is very small. If you set in the test mode gap = 0 then L = Lfe. In that case you do not need to cut the leg in 8 blocks and use the gap fixing plates!

TEST:

In the test the following parameters are changed by hand:

⦁ Turns = 4
⦁ Foil thickness = 1.4mm
⦁ Gap size =0

OUTPUT: Click here for the PDF.