Coupling Inductor Problem Isn't

For some time now I have had trouble with the INDUCTOR_COUPLING element in Multisim. I would place it after placing my inductors then adjust the coupling inductor's settings for the inductors to be coupled and the k constant. Every time I would get a netlist error.

Tonight I found out why: Using INDUCTOR_RATED inductors with INDUCTOR_COUPLING will result in a netlist error. Use a standard inductor instead then modify it from the Properties pane.

Never ever use INDUCTOR_RATED if you plan to couple inductors!

Mutual Inductance in Multisim

For over a year, I have used National Instruments' circuit analysis and design software: Multisim. I have v12, educational version.

Our current homework is about mutual inductance. In class, we received a quick demonstration on how to do couple inductors in v13:

  1. place your inductors, but remember the dot's location is on the left of the inductor when you first place it, so rotate it to position the dot elsewhere
  2. under "Transformer," choose COUPLING_INDUCTOR and place it off by itself, as it is not connected to your circuit
  3. open that element's properties (Ctrl+M)
  4. under "Value," fill in the fields "Coupled inductors list" (by name, like "L1,L2") and "Coupling coefficient"
  5. finish your circuit

However, once I got home, I couldn't find COUPLING_INDUCTOR, rather COUPLED_INDUCTOR, which is not the same. The Help for v12 says COUPLING_INDUCTOR exists, but it apparently does not, perhaps an intentional omission in the academic version. Eventually I got a v12 file with a COUPLING_INDUCTOR element from someone else, so I've been using that file as the template for my assignments. It was very aggravating to learn that cutting and pasting the element into a new file resulted in a netlist error.

One thing I've done is mark the mutual inductance dots by using colored asterisks placed as text. Multisim seems not to offer a way to display the dots, so that is my solution.

This is what COUPLING_INDUCTOR looks like:

20140201-215313.jpg

I did write National Instruments about the netlist errors I kept getting when trying to link inductors before receive the COUPLING_INDUCTOR from someone. Their technical support should get back with me Monday.