hi
Capslock
In most designs the copper shorting ring on the pole tip is
used to reduce the Eddy currents being induced on to the pole piece due to the field of the coil - and the pole piece its self acting as an core
this results in 2 nd harmonic distortion and the copper shorting ring mostly reduces this very well
there have been other material on this like it also has an effect on the inductance and increases the transient responce of the driver
but the latest is copper caps are - out as they reduce the field strength (takes up magnetis gap space etc.) - and a copper -sleeve - ring placed directly in the magnetic gap (embedded into a groove in the pole piece) is - in
Suranjan Das Gupta
Transducer Design Engineer
Capslock
In most designs the copper shorting ring on the pole tip is
used to reduce the Eddy currents being induced on to the pole piece due to the field of the coil - and the pole piece its self acting as an core
this results in 2 nd harmonic distortion and the copper shorting ring mostly reduces this very well
there have been other material on this like it also has an effect on the inductance and increases the transient responce of the driver
but the latest is copper caps are - out as they reduce the field strength (takes up magnetis gap space etc.) - and a copper -sleeve - ring placed directly in the magnetic gap (embedded into a groove in the pole piece) is - in
Suranjan Das Gupta
Transducer Design Engineer
hi
in essence you can call it is a semi - active system one would be sending the ring current -
well when the coil moves outwards of the pole pieces the magnetic flow lines of the coil has a certain flow direction and dimension (a vector force)
when it moves inwards - is the problem - due to the presence of the heavy magnetic field of the magnets (as opposed to the outward stroke) the coils own magnetic file force lines and dimensions change
therefore if you consider the up ward stroke as the upper half of a sine wave
and the inward stroke of the voice coil as the lower half of the sine wave
there will be a non linearily between these half wave forms
arising from two different voice coil field lines and dimensions (structures)
due to the change of the magnetic lines of force - when in the depth of the motorstructure as opposed to out of it
plus there is the effect of both the magnetic forces interacting with each other as discussed earlier in this thread
the inductance ring essentially corrects this change of the magnetic lines of force to bring it about to - as much as possible - as it was in the out ward stroke
it is some thing like cyclotron mentioned of having a same nuber of turns as thet of the voice coil - inductor placed in the motor structure - in series with the voice coil
what one would have (in theory) is an active stabilising ring - though to set it up - one need very powerful FEA analysis tools
i really do not have much material as how grounding the ring actually works - i have figured my own openions about it -
therefore the comment of semi - active system
suranjan das gupta
in essence you can call it is a semi - active system one would be sending the ring current -
well when the coil moves outwards of the pole pieces the magnetic flow lines of the coil has a certain flow direction and dimension (a vector force)
when it moves inwards - is the problem - due to the presence of the heavy magnetic field of the magnets (as opposed to the outward stroke) the coils own magnetic file force lines and dimensions change
therefore if you consider the up ward stroke as the upper half of a sine wave
and the inward stroke of the voice coil as the lower half of the sine wave
there will be a non linearily between these half wave forms
arising from two different voice coil field lines and dimensions (structures)
due to the change of the magnetic lines of force - when in the depth of the motorstructure as opposed to out of it
plus there is the effect of both the magnetic forces interacting with each other as discussed earlier in this thread
the inductance ring essentially corrects this change of the magnetic lines of force to bring it about to - as much as possible - as it was in the out ward stroke
it is some thing like cyclotron mentioned of having a same nuber of turns as thet of the voice coil - inductor placed in the motor structure - in series with the voice coil
what one would have (in theory) is an active stabilising ring - though to set it up - one need very powerful FEA analysis tools
i really do not have much material as how grounding the ring actually works - i have figured my own openions about it -
therefore the comment of semi - active system
suranjan das gupta
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