The AM Forum

Here is one for the thinkers among us. Say you need a big mod reactor, 50 Hy or more, and you have several plate transformers that will not be needed. Can the secondary of one of the 300 - 400 ma units be used as a choke? I just measured a surplus item at 26 Hy!

Bob

You need to measure the inductance with DC flowing through the winding.

The DC needs to equal the expected DC under operating conditions. If the plate current under operating conditions is going to be 300mA, then you need to hook up a DC supply across the winding... to push 300mA through... while you are measuring the inductance. If the DC winding resistance is 100 ohms, then you will need 30VDC across the winding.

With the DC flowing through the winding, you can use a capacitor to couple in AC to determine the inductance.

The issue here is saturation of the core material of the reactor when DC is flowing through it. The inductance of the reactor may be much lower when DC is flowing through it, and that would limit its usefulness in this application.

Stu

Rearrange the core "I" "E" like a choke and you may have something, otherwise it's a waste of a good plate xfmr. 

Fred