Dan
Only two things
1 st
If you have a quantity above 200 take a quote from India for a fully forged top plate -
1) 1008 Billet Steel from foundry in cylinders
2) then forged
3) CNC Machined - Exterior hard shell removed - To bring out the soft steel - and to accurate tolerances
4) Then Hydrogen Annealed
With your Under - Cut of the top plate - CNC machined
2 nd
With a copper ring casted in halves with a locking arrangement - CNC machined and fitted into the rebate
( can send you pics of Forged Poles 1008 Billet , Hydrogen Annealed for triple stacked mags & double stacked mgs )
Suranjan
Only two things
1 st
If you have a quantity above 200 take a quote from India for a fully forged top plate -
1) 1008 Billet Steel from foundry in cylinders
2) then forged
3) CNC Machined - Exterior hard shell removed - To bring out the soft steel - and to accurate tolerances
4) Then Hydrogen Annealed
With your Under - Cut of the top plate - CNC machined
2 nd
With a copper ring casted in halves with a locking arrangement - CNC machined and fitted into the rebate
( can send you pics of Forged Poles 1008 Billet , Hydrogen Annealed for triple stacked mags & double stacked mgs )
Suranjan
capslock said:
Eric,
your 10-15% flux loss must be due to the compared initial gap width, increasing 0,5 mm of an initial gap width of 2 mm is not the same if the gap width was instead initially for instance 3 mm I would guess, so it's not a rule of thumb to say removing 0,5 mm would correspond to xx%, or?
I thought it was some other key issue to not plate in the gap, something else that could affect the magnetical and electrical properties direct and/or indirect.
If the only issue not to use copper in the gap is because of the losses of usefull iron in the magnetic field path I would not be so worried, then we are talking more about trade of and taste whether the field flux loss shloud be compensated with a "bigger" magnet or vice verse!
Dan Wiggins,
just of curiosity, not a big technical issue here but how do you fix those upper plates together to maintain the center axis precision, as the picture shows they are at least not welded on the outside?
Suranjan,
I used just the Paint program in Windows!
Tell if I can assist with new sketches with your description, I could also e-mail the original sketch on which I haven't made any Faradays ring sketches so you can add own Faraday shortings in it.
Regards Michael
Hi
Ultima Thule
Please send me the file with out the rings and the ones with - to help me modify a few
at tubu_cruise@yahoo.co.in
i will try and mail them to you tomorrow -
Suranjan
Ultima Thule
Please send me the file with out the rings and the ones with - to help me modify a few
at tubu_cruise@yahoo.co.in
i will try and mail them to you tomorrow -
Suranjan
Suranjan,
Looked at doing forgings (1000 qty) and stamped laminations, and it's equal or lower cost to laminate. And a lot of flexibility in what you build up - with a small selection of stamped top plates, you can make a VERY wide range of actual top plate buildups.
Had some units built by a larger speaker manufacturer in India, and they chose to laminate as well - I left it up to them to decide to laminate or forge and cut.
Ultima,
We use jigs on the inside and outside, as well as locator pins. Note that is is only critical that the ID of the upper/lower plates (the ones with the smaller ID) are precisely aligned; the center plates can be off a bit without a problem, since they are already recessed from the voice coil.
We line up the IDs of the small ID plates, and the ODs of all plates for a clean look.
Dan Wiggins
Adire Audio
Looked at doing forgings (1000 qty) and stamped laminations, and it's equal or lower cost to laminate. And a lot of flexibility in what you build up - with a small selection of stamped top plates, you can make a VERY wide range of actual top plate buildups.
Had some units built by a larger speaker manufacturer in India, and they chose to laminate as well - I left it up to them to decide to laminate or forge and cut.
Ultima,
We use jigs on the inside and outside, as well as locator pins. Note that is is only critical that the ID of the upper/lower plates (the ones with the smaller ID) are precisely aligned; the center plates can be off a bit without a problem, since they are already recessed from the voice coil.
We line up the IDs of the small ID plates, and the ODs of all plates for a clean look.
Dan Wiggins
Adire Audio
Hi , DAN
From my knowledge - which comes from a thorough discussion with the - Sales Head of one of the largest Companies manufacturing steel here , they now have more or less bought out the steel industry of Thailand . Malysia , Singapore , Taiwan and a lot in China , - Tata Steel
Soft steel CRC sheets - even DD quality is not manufactured above 6.5 mm let alone EDD , you will get HR as thick as you need but in HR - Carbon percentage is higher
As far his knowledge goes it is not manufactured this entire region of South East Asia - and this came right after he was at a training / seminar in France of major steel manufacturers in South East Asia for a month or so
He is yet delving into it - since he is my Uncle
I have followed companies here in South East Asia for eg. -
P - Audio who mention all their steel is CRC - 1008
Well even in their 100 mm top of the line Compression Driver where the highest gauss is required - where P-Audio mentions - 19000 gauss
It is actually averaging betwen 14500 to 15200 gauss , this I have measured in quite a few of their tweeters - from different batches etc.
Since they have made a design mistake in their phase plug and people give it to me to have a corrected one fitted
Suranjan
From my knowledge - which comes from a thorough discussion with the - Sales Head of one of the largest Companies manufacturing steel here , they now have more or less bought out the steel industry of Thailand . Malysia , Singapore , Taiwan and a lot in China , - Tata Steel
Soft steel CRC sheets - even DD quality is not manufactured above 6.5 mm let alone EDD , you will get HR as thick as you need but in HR - Carbon percentage is higher
As far his knowledge goes it is not manufactured this entire region of South East Asia - and this came right after he was at a training / seminar in France of major steel manufacturers in South East Asia for a month or so
He is yet delving into it - since he is my Uncle
I have followed companies here in South East Asia for eg. -
P - Audio who mention all their steel is CRC - 1008
Well even in their 100 mm top of the line Compression Driver where the highest gauss is required - where P-Audio mentions - 19000 gauss
It is actually averaging betwen 14500 to 15200 gauss , this I have measured in quite a few of their tweeters - from different batches etc.
Since they have made a design mistake in their phase plug and people give it to me to have a corrected one fitted
Suranjan
Suranjan,
Having our factory in Chile, we get Chilean steel (mainly 1006 and 1008 at fairly low prices), but even back when sourcing from Asia we found laminations to be lower cost. In fact, the driver shown was built in China, laminated, at a very low price. We typicallyuse 3-6mm thick steel for the lamination layers, which is fairly common and low cost to stamp (some larger houses that stamp their own plates - like Eminence here in the US - can get and stamp as thick as 12mm).
Some buildups use just two pieces for lamination, and the inside edge has half the rebate stamped into it. Glue two pieces together and you have a short (say 6-12mm) top plate. It's how we do most of the small, low cost, short stroke (4-6mm) motors.
Dan Wiggins
Adire Audio
Having our factory in Chile, we get Chilean steel (mainly 1006 and 1008 at fairly low prices), but even back when sourcing from Asia we found laminations to be lower cost. In fact, the driver shown was built in China, laminated, at a very low price. We typicallyuse 3-6mm thick steel for the lamination layers, which is fairly common and low cost to stamp (some larger houses that stamp their own plates - like Eminence here in the US - can get and stamp as thick as 12mm).
Some buildups use just two pieces for lamination, and the inside edge has half the rebate stamped into it. Glue two pieces together and you have a short (say 6-12mm) top plate. It's how we do most of the small, low cost, short stroke (4-6mm) motors.
Dan Wiggins
Adire Audio
Hi
DAN
We had experimented with Lamnates just for knowledge , we had to go over a process of :- Normalising ( Local Term )
It is to align the grains of the sandwithed plates in a furnace at a controlled temperature etc.
1 more thing :-
Since you are touching the liimts of excursion - the designers thought of limiting - over excursion by - design of Spiders and Surround - To limit the driver prior , overexcusrsion can be done with by :-
just letting your drivers - go - with real large spiders and surrounds - and applying a braking coil for over - excursion ,
neways you need to stack up mags - therefore bottoming can be addressed -
Suranjan
DAN
We had experimented with Lamnates just for knowledge , we had to go over a process of :- Normalising ( Local Term )
It is to align the grains of the sandwithed plates in a furnace at a controlled temperature etc.
1 more thing :-
Since you are touching the liimts of excursion - the designers thought of limiting - over excursion by - design of Spiders and Surround - To limit the driver prior , overexcusrsion can be done with by :-
just letting your drivers - go - with real large spiders and surrounds - and applying a braking coil for over - excursion ,
neways you need to stack up mags - therefore bottoming can be addressed -
Suranjan
Hi and thanks for your answers, Dan, Suranjan!
Suranjan , thanks also for being so kind and e-mailing me!
I am a bit puzzled why such a thick aluminum or copper ring around a quite short part of the length of the ceneterpole and also at diffrent heights from bottomplate, and why not having a ring going all the way from bottom plate up to underneath the airgap?
Also what is the diffrence if the ring is in galvanic contact with the pole part or isolated?
I did a fast scan through past posts in this thread, Suranjan mentioned something about the iron is getting saturated in his post #38 but I'm not sure of the meaning in that post and if it apply to my question.
My thought woud be that having the ring or cap or whatever shape in contact with the iron would be better but maybe there are some issues to concider, somebody having any insight what it is about?
Cheers Michael
Suranjan , thanks also for being so kind and e-mailing me!
I am a bit puzzled why such a thick aluminum or copper ring around a quite short part of the length of the ceneterpole and also at diffrent heights from bottomplate, and why not having a ring going all the way from bottom plate up to underneath the airgap?
Also what is the diffrence if the ring is in galvanic contact with the pole part or isolated?
I did a fast scan through past posts in this thread, Suranjan mentioned something about the iron is getting saturated in his post #38 but I'm not sure of the meaning in that post and if it apply to my question.
My thought woud be that having the ring or cap or whatever shape in contact with the iron would be better but maybe there are some issues to concider, somebody having any insight what it is about?
Cheers Michael
Hi
Ultima
My drawings (which I Have Mailed U ) are of the most common - Shorting Rings in use by the more or less Top Ten Driver Manufacturers in the Market today
We have already discussed its application theory
To put any of these to practical use - or position them accurately in a Motor Structure - or their Size -
Is Dependant on POWERFUL FEA MEASUREMENT Tools
Suranjan
Ultima
My drawings (which I Have Mailed U ) are of the most common - Shorting Rings in use by the more or less Top Ten Driver Manufacturers in the Market today
We have already discussed its application theory
To put any of these to practical use - or position them accurately in a Motor Structure - or their Size -
Is Dependant on POWERFUL FEA MEASUREMENT Tools
Suranjan
Bumping up this thread!
Hoping for some new comments from any wise guy, as I still think after have re-read the whole thread twice I still feel not all of my questions in my previous post have been answered.
For instance I would like to know why having the shorting ring, cap, etc. galvanically isolated, or more exactely how does it affect if it is isolated or not and what is the good and bad side with both ways having the shorting ring.
Any helpful soul who would like to help me out, links and search words are also welcome to direct me in any direction so I can at least on my own make researches in the issue.
Regards Michael
PS. if it's really "top secret" things, please PM or e-mail me at least, I would like to discuss it in confidence!
Hoping for some new comments from any wise guy, as I still think after have re-read the whole thread twice I still feel not all of my questions in my previous post have been answered.
For instance I would like to know why having the shorting ring, cap, etc. galvanically isolated, or more exactely how does it affect if it is isolated or not and what is the good and bad side with both ways having the shorting ring.
Any helpful soul who would like to help me out, links and search words are also welcome to direct me in any direction so I can at least on my own make researches in the issue.
Regards Michael
PS. if it's really "top secret" things, please PM or e-mail me at least, I would like to discuss it in confidence!
Hello,
A few things, not all the information at LDSG's webpage at http://ldsg.snippets.org/motors.php3 is correct. For instance what's drawn there as a picture of Scan-Speak's patented SD-1 motor is not Scan-Speak's patented motor structure. That T pole piece which is sandwiched by two rings is patented by McIntosh 1992, US patent number 5151943. Scan-Speak's patented motor is a three ring configuration, which has US patent number 5815587. A while ago I had contacted LDSG author about the misinformation there, he replied that he would correct them, but never had time I guess, or didn't take me seriously which wouldn't be the first time happening.
Anyways, I think you will find a lot of good reading if you visit US patent database and as a starting point look for these patent numbers:
5151943 McIntosh Labs two faraday ring patent
5815587 Scan-Speak three faraday ring patent
3935399 Shorting cap covering the pole piece patent, 1976 (These things have a very old history, like many other things with loudspeakers)
6289106 A more recent one, 1999, but I think is only about how to mechanically attach the cap on the pole, it may give more pointers and other info though
I had also found a 1970's patent where the shorting ring was place to the inner side of the magnet, like the Peerless woofers, but I don't have its number right now.
The US patent page for searching with patent numbers is
http://patft.uspto.gov/netahtml/srchnum.htm
You will need a TIFF viewer on your browser to view the images, there are couple of downloadable freeware TIFF plugins, like AlternaTIFF for instance.
Searching European or Japan patent databases may give more information, if you can read non English European languages or Japanase, I can't.
A few things, not all the information at LDSG's webpage at http://ldsg.snippets.org/motors.php3 is correct. For instance what's drawn there as a picture of Scan-Speak's patented SD-1 motor is not Scan-Speak's patented motor structure. That T pole piece which is sandwiched by two rings is patented by McIntosh 1992, US patent number 5151943. Scan-Speak's patented motor is a three ring configuration, which has US patent number 5815587. A while ago I had contacted LDSG author about the misinformation there, he replied that he would correct them, but never had time I guess, or didn't take me seriously which wouldn't be the first time happening.
Anyways, I think you will find a lot of good reading if you visit US patent database and as a starting point look for these patent numbers:
5151943 McIntosh Labs two faraday ring patent
5815587 Scan-Speak three faraday ring patent
3935399 Shorting cap covering the pole piece patent, 1976 (These things have a very old history, like many other things with loudspeakers)
6289106 A more recent one, 1999, but I think is only about how to mechanically attach the cap on the pole, it may give more pointers and other info though
I had also found a 1970's patent where the shorting ring was place to the inner side of the magnet, like the Peerless woofers, but I don't have its number right now.
The US patent page for searching with patent numbers is
http://patft.uspto.gov/netahtml/srchnum.htm
You will need a TIFF viewer on your browser to view the images, there are couple of downloadable freeware TIFF plugins, like AlternaTIFF for instance.
Searching European or Japan patent databases may give more information, if you can read non English European languages or Japanase, I can't.
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