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#1
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A question about two coils on one form
Hi all,
If you put two coils on one form, but wind one in the opposite direction, Do the currents flow in opposite directions? Mikek PS. opposite winding direction as in clockwise or counter clockwise, or like a left hand and right hand thread. |
#2
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A question about two coils on one form
On 8/8/2019 11:45 AM, amdx wrote:
Hi all, If you put two coils on one form, but wind one in the opposite direction, Do the currents flow in opposite directions? Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek PS. opposite winding direction as in clockwise or counter clockwise, Â*or like a left hand and right hand thread. If it is a continuous coil with only two connections (start to finish) but winding is reversed in the middle of the coil, the current does not reverse. |
#3
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A question about two coils on one form
On 8/9/2019 8:06 AM, John S wrote:
On 8/8/2019 11:45 AM, amdx wrote: Hi all, If you put two coils on one form, but wind one in the opposite direction, Do the currents flow in opposite directions? Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek PS. opposite winding direction as in clockwise or counter clockwise, Â*Â*or like a left hand and right hand thread. If it is a continuous coil with only two connections (start to finish) but winding is reversed in the middle of the coil, the current does not reverse. That wasn't what I ask, but since I posted I did put an answer together. It took me several drawing to get to a final answer that makes it so simple I don't know why I ask the question. I took me several hours to come to the conclusion though. My answer to your question would be, the current does reverse and for your example, the current would be very low. Probably not zero because of time/phase concerns. I have one drawing showing a coil and the right hand rule that gives the answer. file:///C:/Users/Lamont/Dropbox/contra%20wound%20coil%20with%20flux%20and%20curren t%20flow.jpg Mikek |
#4
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A question about two coils on one form
On Tue, 13 Aug 2019 09:29:19 -0500, amdx wrote:
file:///C:/Users/Lamont/Dropbox/contra%20wound%20coil%20with%20flux%20and%20curren t%20flow.jpg Errrrr... Uhhhhh... There's no way we can see a file on your personal computer. |
#5
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A question about two coils on one form
On 8/13/2019 9:29 AM, amdx wrote:
On 8/9/2019 8:06 AM, John S wrote: On 8/8/2019 11:45 AM, amdx wrote: Hi all, If you put two coils on one form, but wind one in the opposite direction, Do the currents flow in opposite directions? Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek PS. opposite winding direction as in clockwise or counter clockwise, Â*Â*or like a left hand and right hand thread. If it is a continuous coil with only two connections (start to finish) but winding is reversed in the middle of the coil, the current does not reverse. Â*That wasn't what I ask, but since I posted I did put an answer together. It took me several drawing to get to a final answer that makes it so simple I don't know why I ask the question. I took me several hours to come to the conclusion though. Â*My answer to your question would be, the current does reverse and for your example, the current would be very low. Probably not zero because of time/phase concerns. I have one drawing showing a coil and the right hand rule that gives the answer. file:///C:/Users/Lamont/Dropbox/contra%20wound%20coil%20with%20flux%20and%20curren t%20flow.jpg Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek The current can not reverse in a series connection. But the magnet field can reverse in the two series windings if one of the windings is reverse wound. |
#6
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A question about two coils on one form
On 8/13/2019 7:26 PM, Allodoxaphobia wrote:
On Tue, 13 Aug 2019 09:29:19 -0500, amdx wrote: file:///C:/Users/Lamont/Dropbox/contra%20wound%20coil%20with%20flux%20and%20curren t%20flow.jpg Errrrr... Uhhhhh... There's no way we can see a file on your personal computer. Thanks for pointing that out. https://www.dropbox.com/s/c4k2hh4syd...0flow.jpg?dl=0 Mikek |
#7
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A question about two coils on one form
On 8/14/2019 7:11 AM, John S wrote:
On 8/13/2019 9:29 AM, amdx wrote: On 8/9/2019 8:06 AM, John S wrote: On 8/8/2019 11:45 AM, amdx wrote: Hi all, If you put two coils on one form, but wind one in the opposite direction, Do the currents flow in opposite directions? Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek PS. opposite winding direction as in clockwise or counter clockwise, Â*Â*or like a left hand and right hand thread. If it is a continuous coil with only two connections (start to finish) but winding is reversed in the middle of the coil, the current does not reverse. Â*Â*That wasn't what I ask, but since I posted I did put an answer together. It took me several drawing to get to a final answer that makes it so simple I don't know why I ask the question. I took me several hours to come to the conclusion though. Â*Â*My answer to your question would be, the current does reverse and for your example, the current would be very low. Probably not zero because of time/phase concerns. I have one drawing showing a coil and the right hand rule that gives the answer. file:///C:/Users/Lamont/Dropbox/contra%20wound%20coil%20with%20flux%20and%20curren t%20flow.jpg Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek The current can not reverse in a series connection. But the magnet field can reverse in the two series windings if one of the windings is reverse wound. I should have added more information. The coil(s) are put in an electromagnetic field, creating a magnetic field around the coil. the magnetic field creates a current in each coil. what is the direction of each of those currents? https://www.dropbox.com/s/c4k2hh4syd...0flow.jpg?dl=0 Mikek PS, it took me hours to get this understood and now, it's like, well ya! |
#8
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A question about two coils on one form
On 8/15/2019 8:46 AM, amdx wrote:
On 8/14/2019 7:11 AM, John S wrote: On 8/13/2019 9:29 AM, amdx wrote: On 8/9/2019 8:06 AM, John S wrote: On 8/8/2019 11:45 AM, amdx wrote: Hi all, If you put two coils on one form, but wind one in the opposite direction, Do the currents flow in opposite directions? Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek PS. opposite winding direction as in clockwise or counter clockwise, Â*Â*or like a left hand and right hand thread. If it is a continuous coil with only two connections (start to finish) but winding is reversed in the middle of the coil, the current does not reverse. Â*Â*That wasn't what I ask, but since I posted I did put an answer together. It took me several drawing to get to a final answer that makes it so simple I don't know why I ask the question. I took me several hours to come to the conclusion though. Â*Â*My answer to your question would be, the current does reverse and for your example, the current would be very low. Probably not zero because of time/phase concerns. I have one drawing showing a coil and the right hand rule that gives the answer. file:///C:/Users/Lamont/Dropbox/contra%20wound%20coil%20with%20flux%20and%20curren t%20flow.jpg Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek The current can not reverse in a series connection. But the magnet field can reverse in the two series windings if one of the windings is reverse wound. Â*I should have added more information. The coil(s) are put in an electromagnetic field, creating a magnetic field around the coil. the magnetic field creates a current in each coil. what is the direction of each of those currents? https://www.dropbox.com/s/c4k2hh4syd...0flow.jpg?dl=0 Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â* Mikek PS, it took me hours to get this understood and now, it's like, well ya! Ok. You have all the answers so go with that. Good luck. |
#9
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A question about two coils on one form
On 8/15/2019 2:41 PM, John S wrote:
On 8/15/2019 8:46 AM, amdx wrote: On 8/14/2019 7:11 AM, John S wrote: On 8/13/2019 9:29 AM, amdx wrote: On 8/9/2019 8:06 AM, John S wrote: On 8/8/2019 11:45 AM, amdx wrote: Hi all, If you put two coils on one form, but wind one in the opposite direction, Do the currents flow in opposite directions? Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek PS. opposite winding direction as in clockwise or counter clockwise, Â*Â*or like a left hand and right hand thread. If it is a continuous coil with only two connections (start to finish) but winding is reversed in the middle of the coil, the current does not reverse. Â*Â*That wasn't what I ask, but since I posted I did put an answer together. It took me several drawing to get to a final answer that makes it so simple I don't know why I ask the question. I took me several hours to come to the conclusion though. Â*Â*My answer to your question would be, the current does reverse and for your example, the current would be very low. Probably not zero because of time/phase concerns. I have one drawing showing a coil and the right hand rule that gives the answer. file:///C:/Users/Lamont/Dropbox/contra%20wound%20coil%20with%20flux%20and%20curren t%20flow.jpg Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek The current can not reverse in a series connection. But the magnet field can reverse in the two series windings if one of the windings is reverse wound. Â*Â*I should have added more information. The coil(s) are put in an electromagnetic field, creating a magnetic field around the coil. the magnetic field creates a current in each coil. what is the direction of each of those currents? https://www.dropbox.com/s/c4k2hh4syd...0flow.jpg?dl=0 Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â* Mikek PS, it took me hours to get this understood and now, it's like, well ya! Ok. You have all the answers so go with that. Good luck. That answer as stated makes me think you disagree. I would like to have the conversation. Clearly is was a slog for me an I could easily have something wrong. I would say my strongest evidence would be that in order to make the contracoil measure maximum inductance with a series connection, you can't just connect the coils in the center and measure from the to outside ends. Please let me know what you think. Mikek |
#10
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A question about two coils on one form
On 8/19/2019 6:12 PM, amdx wrote:
On 8/15/2019 2:41 PM, John S wrote: On 8/15/2019 8:46 AM, amdx wrote: On 8/14/2019 7:11 AM, John S wrote: On 8/13/2019 9:29 AM, amdx wrote: On 8/9/2019 8:06 AM, John S wrote: On 8/8/2019 11:45 AM, amdx wrote: Hi all, If you put two coils on one form, but wind one in the opposite direction, Do the currents flow in opposite directions? Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek PS. opposite winding direction as in clockwise or counter clockwise, Â*Â*or like a left hand and right hand thread. If it is a continuous coil with only two connections (start to finish) but winding is reversed in the middle of the coil, the current does not reverse. Â*Â*That wasn't what I ask, but since I posted I did put an answer together. It took me several drawing to get to a final answer that makes it so simple I don't know why I ask the question. I took me several hours to come to the conclusion though. Â*Â*My answer to your question would be, the current does reverse and for your example, the current would be very low. Probably not zero because of time/phase concerns. I have one drawing showing a coil and the right hand rule that gives the answer. file:///C:/Users/Lamont/Dropbox/contra%20wound%20coil%20with%20flux%20and%20curren t%20flow.jpg Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek The current can not reverse in a series connection. But the magnet field can reverse in the two series windings if one of the windings is reverse wound. Â*Â*I should have added more information. The coil(s) are put in an electromagnetic field, creating a magnetic field around the coil. the magnetic field creates a current in each coil. what is the direction of each of those currents? https://www.dropbox.com/s/c4k2hh4syd...0flow.jpg?dl=0 Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â* Mikek PS, it took me hours to get this understood and now, it's like, well ya! Ok. You have all the answers so go with that. Good luck. Â*That answer as stated makes me think you disagree. I would like to have the conversation. Clearly is was a slog for me an I could easily have something wrong. Â* I would say my strongest evidence would be that in order to make the contracoil measure maximum inductance with a series connection, you can't just connect the coils in the center and measure from the to outside ends. Â*Please let me know what you think. Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Mikek Ok, Mike. Are you familiar with the phasing dots of transformers shown on some symbols and schematics? Wind a coil and put a dot at the start of the winding. Wind another coil in the same direction as the first coil and put a dot at the start of the second winding: ---.UUUUU---- ---.UUUUU---- (The phasing dots are periods) Now connect the two closest ends together, and you get 4x the inductance of one of the coils if you have perfect coupling. Now rotate one of the coils 180 degrees and connect the closest ends together: ---.UUUUU---- ----UUUUU.--- If you have perfect coupling, the inductance is zero. I see no reason the have a contra-wound coil. And you don't have to actually rotate the coil. By simply changing the connections you can achieve the same thing as "contra-wound" coils. BTW transformers and air-wound coils obey the same laws. The difference between them is coupling factor and core losses. |
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