Name: three-phase ac generator windings
Uploaded: 2024-07-08T13:19:57.000Z
Duration: 1 min 21 s
Channel: JoVE

固定巻線で囲まれた回転磁石を備えた三相AC発電機を使用して、三相電圧を生成します。
ステータには、3つの別々のコイルまたは巻線が収納されており、それらの端子は120度離れて配置されています。
ローターが回転すると、その磁場がコイルと交差し、それぞれが120度の位相差を持つ等の大きさの電圧を誘導します。
各コイルは単相発電機として機能し、三相発電機は単相負荷と三相負荷の両方に電力を供給できます。
三相システムでは、3つまたは4つの伝送線路を介して負荷に接続された3つの電圧源があります。これらのソースは、Y 接続またはデルタ接続のいずれかで構成できます。
同じ振幅と周波数で位相差が120度のY接続電圧源の場合、ラインa、b、c、およびニュートラルライン間の電圧は位相電圧であり、バランスが取れており、大きさが等しく、位相が120度ずれています。
風力タービンでは、回転するブレードが発電機のローターを駆動し、ステーターコイルに三相電圧を誘導し、それが変換されてグリッドに伝達されます。

三相電圧の生成

三相交流発電機には、固定子内に回転磁石が配置されたローターがあり、固定子には三相巻線が取り付けられ、相互誘導によって三相電圧を生成します。これらの巻線は、固定子の内周に均等に分散され、電気角で 120 度離れて配置されています。三相固定子巻線は、相と呼ばれる 3 つの個別のコイルまたはコイルのグループで構成され、それぞれが Y (スター) 構成またはデルタ構成で接続されています。

ローターが回転すると、その回転磁界が固定子巻線と交差し、120度の位相差を持つ同じ大きさの電圧を誘導します。各巻線は単相発電機として機能し、三相発電機は単相負荷と三相負荷の両方に電力を供給できます。三相システムは、3 つまたは 4 つの導体を使用して負荷に接続された 3 つの電圧源で構成されます。Y 接続システムでは、電圧源の振幅と周波数は同じで、120 度離れています。ライン a、b、c から中性線までの電圧は、相電圧を表します。これらの電圧は、大きさが等しく、互いに 120 度位相がずれている場合にバランスが取れていると呼ばれます。振幅と周波数が同一で、位相差が 120 度のデルタ接続電圧源では、ライン a、b、c 間の電圧は中性線を介さず、線間電圧と呼ばれます。これらの線間電圧は、大きさが等しく、互いに120度の位相差を維持している場合にバランスが取れていると呼ばれます。

風力タービンでは、回転ブレードが発電機のローターを回転させ、ステータコイルに三相電圧を誘導し、それが変換されてグリッドに送信されます。

固定巻線で囲まれた回転磁石を備えた三相AC発電機を使用して、三相電圧を生成します。
ステーターには3つの...

Education

JoVE Core

Electrical Engineering

電気工学

Unit 1

ユニット1

Three-Phase Circuits

三相回路

KEY TERMS AND CONCEPTS

主要用語および概念

Generation of Three-Phase Voltage

three-phase ac generator windings

A three-phase AC generator uses rotating magnet windings and a stationary stator to make three-phase voltage. The rotor carries a magnet that spins inside the stator. The stator holds the three-phase winding, and mutual induction creates the voltage.

The stator windings are spread evenly around the inside of the stator. They are placed 120 electrical degrees apart. These windings consist of three separate coils, or groups of coils, called phases.

The phases can be connected in a Y, or star, configuration or in a Delta configuration. As the rotor turns, its rotating magnetic field crosses the stator windings. This induces equal voltages with a 120-degree phase difference. Each winding acts like a single-phase generator, so the machine can supply both single-phase and three-phase loads.

A three-phase system uses three voltage sources connected to loads with three or four conductors. In a Y-connected system, the voltages have the same amplitude and frequency and are 120 degrees apart. The voltages from lines a, b, and c to the neutral line are called phase voltages. They are balanced when they are equal in magnitude and spaced 120 degrees apart.

In a Delta-connected source, the voltages also have identical amplitude and frequency with a 120-degree phase difference. These voltages are measured between lines a, b, and c and do not use a neutral line. They are called line voltages, and they are balanced when they stay equal in magnitude and 120 degrees apart.

This generator setup is also used in wind turbines. The spinning blades turn the rotor, which induces three-phase voltage in the stator coils. The electrical output is then transformed and sent to the grid.

Three-Phase AC Generator Windings

three-phase circuits

How Three-Phase Power Delivers Electricity

Three-phase power is a major part of AC power distribution, especially where steady and efficient electricity delivery is needed. AC systems are grouped into single-phase, two-phase, and three-phase systems. These categories help describe how power moves from the source to the load. Single-phase circuits are common in homes. They usually use a two-wire system that connects one AC source to loads. These circuits can supply everyday appliances such as lamps, televisions, and microwaves at 120 V...

generation of three-phase voltage

A three-phase AC generator uses rotating magnet windings and a stationary stator to make three-phase voltage. The rotor carries a magnet that spins inside the stator. The stator holds the three-phase winding, and mutual induction creates the voltage. The stator windings are spread evenly around the inside of the stator. They are placed 120 electrical degrees apart. These windings consist of three separate coils, or groups of coils, called phases. The phases can be connected in a Y, or star,...

three-phase voltages

Three-Phase Power Connections

Three-phase power connections use balanced voltages that are equal in magnitude and separated by 120 degrees. A three-phase generator produces these voltages, and the balance helps reduce power loss while keeping energy delivery steady to connected loads. Three-phase sources can be arranged in either wye or delta form. The loads connected to the system can also use wye or delta. This flexibility gives control over how the system is designed and managed. In a wye connection, one end of each...

the y-to-y circuit

Balanced Wye-to-Wye Neutral Current

A balanced wye-to-wye circuit uses three wye-connected sinusoidal voltage sources and three wye-connected loads. A neutral wire links the neutral node of the source to the neutral node of the load. The load impedance is connected across each phase of the load. The source and load can be connected in either a four-wire or a three-wire arrangement. A three-phase system is balanced when each phase has the same load. In that case, the current flow and phase angle are uniform across the system. If...

the y-to-delta circuit

Wye Source and Delta Load Currents

A balanced wye source and delta load form a common three-phase circuit with no neutral line connection. The source is Y-connected, and the load is delta-connected. To analyze the circuit, the first step is to assume a positive phase sequence. These phase voltages are then used to find the line voltages that appear across the delta load impedances. In the wye source, the phase voltages are V an, V bn, and V cn. In the delta load, the line voltages are V ab, V bc, and V ca. These line voltages...

the delta-to-delta circuit

Balanced Delta-Delta Power Circuit

A balanced delta-delta power circuit uses a delta-connected source and a delta-connected load. The two deltas form a closed loop that creates three separate phases. In this setup, the phase voltages are the same as the line voltages. If the source is in positive sequence, the phase voltages can be written directly, and no neutral wire is needed. The delta-connected load current is found by dividing the phase voltage by the impedance of each phase. For line current, Kirchhoff’s Current Law...

the delta-to-y circuit

Delta-Wye Source and Load Connections

A balanced delta-wye circuit connects a delta-connected source to a wye-connected load. In this setup, the phase voltage of the delta source equals the line voltage of the wye load. The source also sets the line currents that flow into the load. For a balanced system, the phase difference between currents makes it possible to find one line current from the other by using the positive sequence of phases. In the wye-connected load, each phase current equals the line current from the delta source.

power in a three-phase circuit

Balanced Three-Phase Power Calculation

Balanced three-phase power calculation depends on the wye and delta connections used in the circuit. A wye, or star, configuration can use three wires or four wires. A delta configuration connects the components in a closed loop. These connection types change how voltages and currents are arranged, but both are used in three-phase systems. In a balanced three-phase system, instantaneous power is the power at one exact moment. Even though the power in each phase changes over time, the total...

power distribution in three-phase and single phase circuits

power-distribution-in-three-phase-and-single-phase-circuits

Single-Phase vs. Three-Phase Power Loss

Single-phase and three-phase circuits distribute electrical power in different ways. Single-phase power is common in homes, while balanced three-phase power is widely used in industrial settings with heavy machinery. Both systems deliver energy, but their current flow and wire needs are not the same. A single-phase circuit usually uses a two-wire system. The current depends on the power absorbed by the load and the line voltage. Because wire loss from resistance follows the square of the...

line loss

Reducing Power Loss in Three-Phase Lines

Three-phase power lines can lose energy as electricity travels from the source to the load. This line loss affects how efficiently power reaches the load. In balanced three-phase circuits, the symmetry makes the analysis easier because one phase can represent the whole system. The source-load connection can use wye, also called star, or delta configurations. These setups change the relationship between line voltage, phase voltage, line current, and phase current. A per-phase equivalent circuit...

reducing line loss

Cutting Heat Loss in Three-Phase Lines

Three-phase power systems can lose energy as heat in transmission lines because the wires have resistance. This line loss becomes important when electricity travels over a distance. A common solution is to use transformers to change the voltage and current in the system. The setup uses two three-phase transformers. A step-up transformer is placed at the source, and a step-down transformer is placed at the load. Raising the voltage at the source lowers the current in the transmission lines, and...

key terms and concepts

Learn how a rotating rotor and stationary stator windings create balanced three-phase voltages in Y and Delta systems, including a wind turbine example.

Three-Phase AC Generator Windings | JoVE K12

JoVE Core 電気工学 は、電気回路の基本概念と回路解析テクニックを網羅したアニメーションビデオシリーズです。オペアンプと回路変換および 1 次・ 2 次回路の概念を網羅しています。実験を撮影した実写動画では、設計例や現代社会での応用が含まれており、複雑な概念も分かりやすく学習いただけます。

electrical engineering

Three-Phase AC Generator Windings

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