Originally posted by bistander
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The guys are busy over on the Figuera build threads (yep, they just started a new one) having fun and seemingly not accomplishing much "build". Not that I mind, but CM did post something interesting.
From the book: The Electromagnet and Electromagnetic Mechanism by Silvanus P Thompson, pg 55 & 56.
I was wondering where he had come up with consequent poles. I have in the past used the consequent pole technique with motors. Works very well. Looking up the definition I see where it can also apply to internal magnet poles. Although I disagree with the definition because I contend that a magnet pole needs to be at the surface, the definition is out there.
Now, the figure in the attachment from Mr. Thompson's book, as a stand-alone object, meaning not under the influence of any significant external magnetic flux fields, I don't believe has the internal fields and poles shown and described. Mr. Thompson calls the internal poles consequent poles. He may as well called them imaginary poles. I guess it is possible that some flux leakage could exist and cause a very weak pole on the surface of the toroid at or near the brushes. But toroids constructed of good material in proper portions have very little leakage and is considered negligible. I base my opinions on my understanding of Ampere's Law.
Electrostatics
On the cover of the book is the date 1888. Maxwell published Ampere's Law in his equation circa 1860. I clicked my way through Mr. Thompson's book today. Like 3-400 pages. Read some, skipped a lot. I did not see the mention of Ampere's Law anywhere. One spot talks of units for current being the Ampere, recently changed from the Weber. It may have been that Mr. Thompson was unfamiliar with Ampere's Law, or disagreed with it. But the book was written when all this electromagnetic stuff was very new. I also noted only one other place in the book where a toroid shape was found. Search for toroid, toroidal, torus found nothing. I'm thinking the author didn't care much at all about the thing.
I am aware of the Gramme ring motor. I have designed and built several. And the Gramme ring armature does resemble the continuous wound toroid inductor being discussed for use as part G on the Figuera generator. However there is a huge difference. The toroid inductor is a stand-alone device meant to be void of external fields. Typical leakage of 1% means essentially all the flux (or magnetic field) is produced inside the toroid core and stays there.
To the contrary, the Gramme ring armature is made to operate in an external magnetic field. Like this:
vs the toroidal inductor:
The inductor is intended to operate in the absence of external magnetic fields.
The Gramme ring armature for that 2 pole dynamo has 2 parallel magnetic circuits and has flux cutting the surface of the core. The inductor has a single loop path and no flux cutting the core surface. These are very big differences in the circuit analysis.
People can imagine all sorts of things going on with magnetics. I'm telling you the way I see it and the way I was taught and what has worked for me many years and what agrees with mainstream science. Just go on with inductor design. Don't let the facts get in your way.
Regards,
bi
From the book: The Electromagnet and Electromagnetic Mechanism by Silvanus P Thompson, pg 55 & 56.
I was wondering where he had come up with consequent poles. I have in the past used the consequent pole technique with motors. Works very well. Looking up the definition I see where it can also apply to internal magnet poles. Although I disagree with the definition because I contend that a magnet pole needs to be at the surface, the definition is out there.
Now, the figure in the attachment from Mr. Thompson's book, as a stand-alone object, meaning not under the influence of any significant external magnetic flux fields, I don't believe has the internal fields and poles shown and described. Mr. Thompson calls the internal poles consequent poles. He may as well called them imaginary poles. I guess it is possible that some flux leakage could exist and cause a very weak pole on the surface of the toroid at or near the brushes. But toroids constructed of good material in proper portions have very little leakage and is considered negligible. I base my opinions on my understanding of Ampere's Law.
Electrostatics
On the cover of the book is the date 1888. Maxwell published Ampere's Law in his equation circa 1860. I clicked my way through Mr. Thompson's book today. Like 3-400 pages. Read some, skipped a lot. I did not see the mention of Ampere's Law anywhere. One spot talks of units for current being the Ampere, recently changed from the Weber. It may have been that Mr. Thompson was unfamiliar with Ampere's Law, or disagreed with it. But the book was written when all this electromagnetic stuff was very new. I also noted only one other place in the book where a toroid shape was found. Search for toroid, toroidal, torus found nothing. I'm thinking the author didn't care much at all about the thing.
I am aware of the Gramme ring motor. I have designed and built several. And the Gramme ring armature does resemble the continuous wound toroid inductor being discussed for use as part G on the Figuera generator. However there is a huge difference. The toroid inductor is a stand-alone device meant to be void of external fields. Typical leakage of 1% means essentially all the flux (or magnetic field) is produced inside the toroid core and stays there.
To the contrary, the Gramme ring armature is made to operate in an external magnetic field. Like this:
vs the toroidal inductor:
The inductor is intended to operate in the absence of external magnetic fields.
The Gramme ring armature for that 2 pole dynamo has 2 parallel magnetic circuits and has flux cutting the surface of the core. The inductor has a single loop path and no flux cutting the core surface. These are very big differences in the circuit analysis.
People can imagine all sorts of things going on with magnetics. I'm telling you the way I see it and the way I was taught and what has worked for me many years and what agrees with mainstream science. Just go on with inductor design. Don't let the facts get in your way.
Regards,
bi
Bistander,
By the way, thanks a lot for the help on measuring the Exciter Circuit Amps on Generator...it worked out fine based on last diagram, I am making a video of it with full diagram. The total running amperage was at start of like 2.5 and as machine warms up (stabilize speed and electromagnetics) became 2.0 amps...which actually delivers about same 400 VA (Watts) you were talking about on the whole small gen exciter system within the big one of 4400 Watts.
About your above comments related to Thompson and the Gramme Ring part on that earlier edition book...I would not be so "finally conclusive"...
DYNAMO-ELECTRIC MACHINERY 1903 Fifth Edition
I recommend you read now his 1903 Fifth Edition, (Now he had enough time to review Ampere's Laws pretty well, don't you think?)...However, still maintains the same exact position on his writings about double poles on continuous Ring (Toroidal) Rotor...and this time he goes even further on this Chapter...to a very interesting comparison to Drum Armatures versus Toroidal ones...start from Page 74 on Google Book...and 70 on direct book mark link above.
Regards
Ufopolitics
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