Name: faraday disk dynamo and dc output
Uploaded: 2023-09-18T17:11:16.000Z
Duration: 1 min 23 s
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Physical Science

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Motion and Stability- Forces and Interactions

PS.PSc.6.5

Faraday Disk Dynamo

La dynamo à disque de Faraday est un générateur de courant continu qui fonctionne sur le principe de l’induction.
Il s’agit d’un disque conducteur tournant à vitesse angulaire constante via un arbre conducteur, qui est placé dans un champ magnétique uniforme perpendiculaire au plan du disque. La rotation du disque induit une f.é.m. en mouvement.
Considérons un petit segment du disque avec un vecteur vitesse tangent à celui-ci. La force magnétique sur ce segment est radiale vers l’extérieur. Cela accumule des charges positives gratuites vers le bord et des charges négatives libres vers le centre, ce qui entraîne des f.é.m.
En intégrant l’équation de la f.é.m. dans les limites de la longueur du segment et en substituant l’intensité du vecteur vitesse, on obtient l’intensité de la f.é.m. en mouvement.
Ce disque peut être connecté au circuit via deux balais fixes, qui conduisent le courant à travers la boucle fermée.
Selon la loi de Lenz, le courant induit s'oppose à la vitesse angulaire constante du disque. Il faut donc travailler pour maintenir le disque en rotation à une vitesse angulaire constante.

<ol>
	<li>Young, H.D et Freedman, R.A. (2012). La physique universitaire avec la physique moderne. San Francisco, Californie : Pearson. Section 29.4, pages 971.</li>
</ol>

dynamo à disque de faraday

Une dynamo à disque de Faraday est un générateur de courant continu, produisant une force électromotrice qui est constante dans le temps. Il est constitué d'un disque conducteur qui tourne à une vitesse angulaire constante dans un champ magnétique perpendiculaire au plan du disque. La rotation du disque provoque un changement de flux magnétique, ce qui induit une force électromotrice, entraînant le développement de charges opposées sur le bord et au centre du disque. La polarité de la force électromotrice induite peut être déterminée par la direction du champ magnétique et la direction de rotation du disque. Si le disque en rotation est connecté à un circuit externe à l'aide de brosses, un courant induit circule.

Selon la loi de Lenz, la force électromotrice induite s'oppose toujours à la cause qui la produit. Pour la dynamo à disque de Faraday, la force électromotrice induite s'oppose à la rotation du disque. Par conséquent, une alimentation externe doit être fournie pour maintenir le disque en rotation à une vitesse angulaire constante.

La force électromotrice induite dans une telle dynamo peut varier de quelques millivolts à quelques volts. L'amplitude de la force électromotrice induite peut être encore améliorée en connectant plusieurs générateurs en série ou en augmentant la force du champ magnétique, le rayon du disque et la vitesse angulaire du disque.

Dynamo à disque de Faraday

Une dynamo à disque de Faraday est un générateur de courant continu, produisant une f.é.m. constante dans le temps. Il se compose d’un disque conducteur qui tourne avec une ...

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faraday disk dynamo and dc output

A Faraday disk dynamo is a DC generator that produces an emf constant in time. It uses a conducting disk that spins at constant angular velocity in a magnetic field. The magnetic field is perpendicular to the plane of the disk.

As the disk rotates, the magnetic flux changes and an emf is induced. This causes opposite charges to build up at the rim and at the center of the disk. The direction of the induced emf depends on the direction of the magnetic field and the direction of rotation.

If brushes connect the rotating disk to an external circuit, an induced current flows. Lenz’s law explains that the induced emf opposes the cause that creates it. In this case, the emf opposes the rotation of the disk, so outside power is needed to keep the disk moving at a constant angular velocity.

The induced emf in a Faraday disk dynamo can range from a few millivolts to a few volts. Its size can be increased by connecting multiple generators in series. It can also be raised by using a stronger magnetic field, a larger disk radius, or a faster disk rotation.

Faraday Disk Dynamo and DC Output

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faraday disk dynamo

A Faraday disk dynamo is a DC generator that produces an emf constant in time. It uses a conducting disk that spins at constant angular velocity in a magnetic field. The magnetic field is perpendicular to the plane of the disk. As the disk rotates, the magnetic flux changes and an emf is induced. This causes opposite charges to build up at the rim and at the center of the disk. The direction of the induced emf depends on the direction of the magnetic field and the direction of rotation. If...

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key terms and concepts

Learn how a Faraday disk dynamo makes steady DC output, builds charge on the disk, and uses Lenz’s law to resist rotation.

Faraday Disk Dynamo and DC Output | JoVE K12

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Faraday Disk Dynamo and DC Output

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