Name: faraday disk dynamo and dc output
Uploaded: 2023-09-18T17:11:16.000Z
Duration: 1 min 23 s
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K12 Standards

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North Carolina K-12 Science Standard Course of Study

9-12

Physical Science

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Motion and Stability- Forces and Interactions

PS.PSc.6.5

Faraday Disk Dynamo

Der Faradaysche Scheibendynamo ist ein Gleichstromgenerator, der nach dem Prinzip der Induktion arbeitet.
Es besteht aus einer leitenden Scheibe, die sich mit konstanter Winkelgeschwindigkeit über eine leitende Welle dreht, die in einem gleichmäßigen Magnetfeld senkrecht zur Ebene der Scheibe angeordnet ist. Die Drehung der Scheibe induziert eine Bewegungs-EMK in ihr.
Betrachten Sie ein kleines Segment der Scheibe mit einem Geschwindigkeitsvektor, der tangential dazu verläuft. Die Magnetkraft auf dieses Segment ist radial nach außen. Dadurch werden freie positive Ladungen in Richtung Rand und freie negative Ladungen in Richtung Zentrum akkumuliert, was zu einer EMK führt.
Integriert man die EMK-Gleichung innerhalb der Grenzen der Segmentlänge und setzt man die Größe des Geschwindigkeitsvektors ein, erhält man die Größe der Bewegungs-EMK.
Diese Scheibe kann über zwei stationäre Bürsten, die den Strom über den geschlossenen Regelkreis leiten, mit dem Stromkreis verbunden werden.
Nach dem Lenzschen Gesetz steht der induzierte Strom der konstanten Winkelgeschwindigkeit der Scheibe entgegen. Es muss also daran gearbeitet werden, dass sich die Scheibe mit konstanter Winkelgeschwindigkeit dreht.

<ol>
	<li>Young, H.D. und Freedman, R.A. (2012). Universitätsphysik mit moderner Physik. San Francisco, Kalifornien: Pearson. Abschnitt 29.4, Seite 971.</li>
</ol>

faraday-scheibendynamo

Ein Faraday-Scheibendynamo ist ein Gleichstromgenerator, der eine zeitlich konstante elektrische Spannung erzeugt. Er besteht aus einer leitenden Scheibe, die sich mit einer konstanten Winkelgeschwindigkeit im magnetischen Feld dreht, senkrecht zur Ebene der Scheibe. Die Rotation der Scheibe führt zu einer Änderung des magnetischen Flusses, der eine Spannung induziert und eine entgegengesetzte Ladungen am Rand und im Zentrum der Scheibe verursacht. Die Polarität der induzierten emf kann durch die Richtung des magnetischen Feldes und die Richtung der Rotation der Scheibe bestimmt werden. Wenn die rotierende Scheibe über Bürsten mit einem externen Stromkreis verbunden ist, fließt ein induzierter Strom.

Nach der Lenz'schen Regel ist die induzierte EMK immer der Ursache entgegengesetzt, die sie erzeugt. Beim Faraday-Scheibendynamo wirkt die induzierte EMK der Drehung der Scheibe entgegen. Daher muss externe Energie zugeführt werden, damit sich die Scheibe mit konstanter Winkelgeschwindigkeit dreht.

Die induzierte EMK in einem solchen Dynamo kann von einigen Millivolt bis zu einigen Volt reichen. Die Größe der induzierten EMK kann weiter erhöht werden, indem man mehrere Generatoren in Reihe schaltet oder die Magnetfeldstärke, den Scheibenradius und die Winkelgeschwindigkeit der Scheibe erhöht.

Faraday-Scheibendynamo

Ein Faradayscher Scheibendynamo ist ein Gleichstromgenerator, der eine zeitlich konstante EMK erzeugt. Es besteht aus einer leitenden Scheibe, die sich mit einem konstanten Winkel ...

Education

Lehre

JoVE Core

Physics

Physik

Unit 1

Einheit 1

Electromagnetic Induction

Elektromagnetische Induktion

KEY TERMS AND CONCEPTS

KERNBEGRIFFE UND KONZEPTE

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

induction

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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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