cw and ccw transformer secondary

Question

The secondary winding of a transformer consists of two windings in parallel, however they share the same core. They have the same number of turns, one cw the other ccw. Will the corresponding magnetic fields cancel each other out?

Answer 1

If you passed a current through a secondary which consisted of two half windings in either anti-series or anti-parallel, then the magnetic fields due to the currents would cancel out to zero.

You have specified secondaries though. Another way to look at it would be that the magnetic field in the core due to a primary excitation would create equal voltages in the two parts of the secondary. Let's call those voltages V. If they were in series, you'd get 2V out. If in parallel, you'd get just V. If they were in anti-series, you would get zero volts out because the two voltages oppose each other. If they were in anti-parallel, you would have short-circuited turns, and would get zero voltage out with a large current flowing, followed by smoke and fire.

Your drawing appears to show the two windings in parallel (I'm trying to infer the polarity of each winding from the representation of each solenoid, but I may be wrong), so you'll simply get the voltage V corresponding to one winding out.

When we draw transformers, we tend to specify that all windings are wound the same way round, then we specify the start of each winding with a dot. All dots then have the same polarity. This avoids the problems that you run into with your drawing method, trying to infer the polarity of the winding from the detail way you've drawn the winding. When draughtsmen of old drew transformers with a stencil, and the same thing tends to happen with CAD today, all windings are drawn the same, there's no information in the ambiguous perspective representation of a solenoid.