Author Topic: Transformer winding current direction  (Read 4306 times)

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Offline steve13579Topic starter

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Transformer winding current direction
« on: June 26, 2015, 07:06:41 pm »
I decided to look up images of transformers and the current in direction on the primary coil and the induced current direction on the secondary coil. The only problem is the images seemed to contradict each other. Which one is correct? Edit: I can only attach one, the only difference is the other one had a different turns ratio and the current on the secondary is in the other direction. Should I make another post and attach it?
« Last Edit: June 26, 2015, 07:35:13 pm by steve13579 »
 

Offline dadler

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Offline steve13579Topic starter

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Re: Transformer winding current direction
« Reply #2 on: June 26, 2015, 09:37:55 pm »
I want to make sure I am applying that correctly. https://en.wikipedia.org/wiki/Transformer
If you look on that other wikipedia page there are two pictures of transformers where the core flux is displayed and current direction indicated. They seem to be different and I believe image with the blue and red colors is wrong and the image i attached earlier from that page which is only a gray image is correct. Am I correct in this evaluation? 
 

Offline IanB

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Re: Transformer winding current direction
« Reply #3 on: June 26, 2015, 11:25:13 pm »
I believe the diagram on Wikipedia with the blue and red coils is correct, and the gray image attached to the first post is incorrect.

This is because the back EMF will always try to oppose the applied EMF, and therefore the induced current will tend to flow in the opposite direction to the applied current. If the primary current is in a clockwise direction the secondary current will be in an anti-clockwise direction. (But turn direction must always be considered relative to the flux direction in the magnetic loop. Before considering clockwise or anticlockwise one must first be facing in the direction of the magnetic flux.)
 

Offline steve13579Topic starter

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Re: Transformer winding current direction
« Reply #4 on: June 26, 2015, 11:35:45 pm »
I had it backwards, thanks for that! I forgot to think of the secondary as an induced current rather than a supplied one! 
 


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