I'm sorry, but as of my last knowledge update in September 2021, there is no widely recognized concept called "transformer polarity" in the context of technology, electrical engineering, or natural sciences. It's possible that this concept has emerged or become relevant after my last update.
If you could provide more context or details about what you mean by "transformer polarity," I'd be happy to help you understand it to the best of my ability based on the information available up to September 2021.