Why is three-phase voltage represented by three line segments?

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1. **In terms of physical significance**
- Three-phase voltage is composed of three alternating electromotive forces with the same frequency, equal amplitude, and a phase difference of 120°. Representing three-phase voltage with three line segments can intuitively reflect the independence and mutual relationship of these three electromotive forces in time and space. Each line segment represents one phase, so that the phase difference between the three phases can be clearly seen. For example, in a three-phase alternator, there are three windings, namely phase A, phase B, and phase C, on the stator. They are spatially 120° apart from each other. When the generator rotates, the electromotive forces induced in the three windings also differ from each other by 120° in time. Using three line segments can well simulate this physical state, as if each line segment is the path of the electromotive force change generated by one winding.
2. **Convenience in analysis and calculation**
- In the analysis of three-phase circuits, using three line segments to represent three-phase voltage is helpful for vector analysis. The three-phase voltage can be regarded as three vectors, which have the same magnitude (amplitude) and their directions (phases) differ from each other by 120°. Through this vector representation method, it is more convenient to calculate parameters such as power, current, and voltage drop in three-phase circuits. For example, when calculating the power of a three-phase balanced load (such as a three-phase motor), according to the three-phase power formula \(P = \sqrt{3}U_{L}I_{L}\cos\varphi\) (where \(U_{L}\) is the line voltage, \(I_{L}\) is the line current, and \(\cos\varphi\) is the power factor), representing the three-phase voltage with vectors can clearly understand the relationship between the line voltage and the phase voltage (the line voltage is \(\sqrt{3}\) times the phase voltage), so as to accurately calculate the power.
3. **Intuitiveness of circuit connection**
- For the connection methods of three-phase circuits, such as star (Y-shaped) connection and delta (△-shaped) connection, representing three-phase voltage with three line segments can make people intuitively understand the connection of the circuit. In the star connection, the ends (or starting ends) of the three-phase power supply are connected together to form a neutral point, and the other ends of the three line segments (three-phase voltage) are connected to the load. This connection method can be clearly depicted with three line segments. Similarly, in the delta connection, the three line segments of the three-phase voltage are connected end to end in sequence to form a closed loop and are connected to the load. This connection method can also be clearly understood through the representation of three line segments, which is convenient for engineers and technicians to design, install, and troubleshoot the circuit. #tiktokrefugee#cat#tiktokban#china#抖音难民#Switchboard#power equipment#power box#switch box#electric substation#electrical substation#substations#power substation #transformer#Power transformer#step up transformer#step up transformers#power transformers#step-down transformer#electric vehicle charging station/电动汽车充电桩#circuit breaker#car charging#electric car charging stations#chargepoint/充电#ev charging stations#electrical switchgear#switchboards#electrical box#electrical boxes#russo power equipment#power equipment#electric#chargepoint charging station#chargepoint. inc.#chargepoint charger#step down transformer#dry type transformer#distribution substation#step up transformer#power box#Power transformer#Power transformers#low voltage switchgear#high voltage switchgear#Electrical Equipment#power equipment#power transfarmer#Power Substations#types of transformer#single phase transformer#three phase transformer#distribution transformer#transformer price#25 kva transformer price#25 kva transformer weight#220 kv substation#mobile transformer#100 kva transformer price#Pad mounted