How to construct a transformer circuit in PSpice?

[Heidi]

Dear friends,

I would like to construct a transformer circuit in PSpice, but the transformer's winding is a little different than usual, as shown in the figure below. Can you please give me some hints of how to do it? There seems no way to specify the dot placement in the XFRM_LINEAR part.

Thank you!

 

[alec_t]

Don't know Pspice, but in LTspice you would place two inductors on the schematic, with one rotated 180° relative to the other.
Example: If L1 (1mH) is between node N001 and ground, and L2 (10mH) is between node N002 and ground the netlist would be

L1 N001 0 1m
L2 0 N002 10m

i.e the inductor orientation determines the order of the listed nodes.

 

[MikeMl]

Dear friends,

I would like to construct a transformer circuit in PSpice, but the transformer's winding is a little different than usual, as shown in the figure below. Can you please give me some hints of how to do it? There seems no way to specify the dot placement in the XFRM_LINEAR part.

Thank you!

LTSpice schematic, resulting netlist and waveforms. I'm showing current direction on the schematic with the secondary inverted.

The dot placement is implied by the node order on the respective nodes.

 

[JoeJester]

The dot placement illustrates phasing. In your diagram, the secondary should is 180 degrees out of phase with the primary.

In cases where there is no dot on the software, like TINA, coupled inductors phasing can be changed by the sign of the k signal, with - having the 180 degree phasing.

Those dots are very old school.

I've worked on equipment from the 40s through the 60s with the dots on the transformer symbols.

 

[Heidi]

I've got it. Thank you, friends.

In PSpice, I would also need the K_Linear part to specify a value for the coupling coefficient K and which inductors to be coupled. The dotted terminal of a inductor in PSpice is at the first pin and that is on the left side when the inductor is placed on Schematic. You might need to rotate the inductor to place the dotted terminal to the position you desire, like alec_t suggested.

I have another question. Do transformers in real life have a transient state as inductors? If they did, how could we estimate the time constant?

Thank you!