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

גנרטור AC תלת פאזי עם מגנט מסתובב מוקף פיתולים נייחים משמש ליצירת מתחים תלת פאזיים.
הסטטור מכיל שלושה סלילים או פיתולים נפרדים, כאשר הדקים שלהם ממוקמים במרחק של 120 מעלות זה מזה.
כאשר הרוטור מסתובב, השדה המגנטי שלו מצטלב עם הסלילים, וגורם למתחים בעוצמה שווה, כל אחד עם הפרש פאזה של 120 מעלות.
כל סליל פועל כגנרטור חד-פאזי, המאפשר לגנרטור התלת-פאזי להפעיל הן עומסים חד-פאזיים והן תלת-פאזיים.
למערכת תלת פאזית שלושה מקורות מתח המחוברים לעומסים באמצעות שלושה או ארבעה קווי תמסורת. ניתן להגדיר מקורות אלה בחיבור Y או דלתא.
עבור מקורות מתח המחוברים ל-Y בעלי אותה משרעת ותדירות והפרש פאזה של 120 מעלות, המתחים בין קווים a, b, c והקו הניטרלי הם מתחי הפאזה, שהם מאוזנים, בעלי גודל שווה, ונמצאים מחוץ לפאזה ב-120 מעלות.
בטורבינת רוח, הלהבים המסתובבים מניעים את הרוטור של הגנרטור, וגורמים למתח תלת פאזי בסלילי הסטטור, אשר לאחר מכן משתנה ומועבר לרשת.

יצירת מתח תלת-פאזי

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גנרטור AC תלת-פאזי כולל רוטור עם מגנט מסתובב הממוקם בתוך הסטטור, שבו מותקנים פיתולים תלת-פאזיים נייחים ליצירת מתחים תלת-פאזיים באמצעות השראה הדדית. הפיתולים הללו מחולקים באופן שווה סביב ההיקף הפנימי של הסטטור ומסודרים במרחק של 120 מעלות חשמליות זה מזה. פיתולי הסטטור התלת-פאזיים מורכבים משלושה סלילים נפרדים או קבוצות של סלילים, הידועים כפאזות, שכל אחד מהם מחובר בתצורת Y (כוכב) או בתצורת דלתא (Δ).

כשהרוטור מסתובב, השדה המגנטי המסתובב שלו מצטלב עם פיתולי הסטטור וגורם למתחים בגודל שווה, בעלי הפרש פאזה של 120 מעלות. כל פיתול פועל כגנרטור חד-פאזי, המאפשר לגנרטור התלת-פאזי להפעיל עומסים חד-פאזיים וגם תלת-פאזיים. המערכת התלת-פאזית כוללת שלושה מקורות מתח המחוברים לעומסים באמצעות שלושה או ארבעה מוליכים. במערכת המחוברת בתצורת Y, למקורות המתח יש משרעת ותדר זהים ומופרדים ב-120 מעלות; המתחים על פני הקווים b, a ו-c לקו הנייטרלי מייצגים את מתחי הפאזה. מתחים אלו נקראים מאוזנים כאשר הם שווים בגודלם ומוסטים ב-120 מעלות זה מזה. במקור מתח המחובר בתצורת דלתא (Δ) עם משרעת ותדר זהים, והפרש פאזה של 120 מעלות, המתחים בין הקווים b, a ו-c לא כוללים קו נייטרלי והם ידועים כמתחי קו. מתחי קו אלו נקראים מאוזנים כאשר הם שווים בגודלם ושומרים על הפרש פאזה של 120 מעלות זה מזה.

בטורבינת רוח, הלהבים המסתובבים מסובבים את הרוטור של הגנרטור, יוצרים מתח תלת-פאזי בסלילי הסטטור, שמומר ומועבר לרשת.

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גנרטור AC תלת פאזי עם מגנט מסתובב מוקף פיתולים נייחים משמש ליצירת מתחים תלת פאזיים.
הסטטור מאכלס שלושה ...

Education

JoVE Core

Electrical Engineering

הנדסה חשמלית

Unit 1

יחידה 1

Three-Phase Circuits

מעגלי תלת-פאזה

KEY TERMS AND CONCEPTS

מונחים ומושגים מרכזיים

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 Electrical Engineering offers easy-to-understand animated videos that cover fundamental concepts of electric circuits along with circuit analysis techniques. It incorporates first-order and second-order circuits using operational amplifiers and circuit transformation concepts. The inclusion of practical design examples and real-world applications through scientist-in-action videos adds significant educational value, making complex concepts accessible.

electrical engineering

Three-Phase AC Generator Windings

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