Recent content by FusionJim

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    I Motional EMF in Faraday disc, co-rotating magnet axial mean flux

    No , the magnet is not a toroid like that, it s a permanent ring magnet but cut in half, so closer to this.
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    I Motional EMF in Faraday disc, co-rotating magnet axial mean flux

    Just imagine the usual toroidal ring magnet but cut in half. this half ring is rigidly attached to the disc and rotates with it. Assume the flux doesn't return back through the disc plane but instead loops around and comes back through the stationary loop part. The red half in the drawing...
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    I Motional EMF in Faraday disc, co-rotating magnet axial mean flux

    So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not...
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    Vacuum cleaner series universal motor triac control board

    @ Guineafowl I found a replacement controller, and a different motor that has roughly the same size. now it works it seems. This motor that I had previously, I believe the windings either in stator or rotor armature had shorted because even with the new added controller it still heated up fast...
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    Vacuum cleaner series universal motor triac control board

    Long story short, I got a vacuum cleaner with a standard universal series motor inside. It also had the TRIAC pcb with a potentiometer and a triac/thyristor to control the RPM which allowed to control the suction power. Some moisture got on the pcb and it shorted. I simply took it out since I...
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    Flux direction through core

    @renormalize The split I was talking about exists in the area of the core where the coils are located. In that area the core is not one solid core but instead has two parallel legs with a gap between them. As can be seen in the "above view". @berkeman Yes I believe I am aware of those terms...
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    Flux direction through core

    Suppose there is a rectangular core. At one part of the core it is split in two identical parallel sections , each section has a coil around it. Both coils are identical and current runs in the same direction through both. The magnetic flux within the core is created by the coils. My question is...
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    I Charge movement relative to magnetic field frame dependence/invariance

    I suppose one thing is certain. The E field that will result from a magnet being moved/rotated in any other way than around it's field symmetry axis is a non conservative E field? Meaning that the field lines do not end on surfaces perpendicularly to them like they would from an electrostatic...
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    I Charge movement relative to magnetic field frame dependence/invariance

    @TSny thank you for the reply. I realized long ago that magnetic field lines are just a man made concept, so we only truly have field strength and geometry as the only physical quantities. If this is the case then it seems weird that a non axis symmetric magnet co-rotates with the disk and no...
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    I Charge movement relative to magnetic field frame dependence/invariance

    The Faraday disc generates current if spinning in a homogeneous magnetic field, it also generates current if there is a non symmetric magnetic field but then the magnet producing that field has to be kept stationary with respect to the disc. In fact back in Faraday's time he had first a field...
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    Submarine noise level reduction, stealth question

    Hmm , I've seen industry companies selling large DC motors advertizing them publicly as for use in submarines like the Siemens permasyn type, but i thought their mistly for diesel subs, so your saying nuclear subs drive the prop directly from turbine vua a reduction gearset? Ni electric motor on...
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    Submarine noise level reduction, stealth question

    I've found online some failed projects that some navy subcontractors have done in the past with regards to creating a truly silent motor for submarine propulsion. IIRC it was General Atomics that tried a homopolar motor for exactly this purpose. I don't know for sure but it seems to me that...
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    Faraday disc voltage increase

    Thank you @Baluncore for your response, I have been aware that it is possible to use liquid metal brushes to decrease the contact resistance. But my question was more theoretical than practical. I am interested to understand a situation where the current through the disc is started by a voltage...
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    Faraday disc voltage increase

    Just a quick question. A Faraday disc - worlds first electric generator, since the time it was invented has been and stayed impractical due to the very low voltage that it produces. It has very low resistance/impedance and could in theory produce large amperage if the current path had low enough...
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    Capacitor plate current skin effect

    Well , is the surface current that you talk about parallel to the plate surface or perpendicular? Because @Ivan Nikiforov claims and shows even with an animation that there is only perpendicular movement of electrons due to the change in plate location. You left out that distinction but that is...
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