三相電力 計算ツール
有効・皮相・無効電力を算出
Required Parameters
Waiting for input data...
Quick Answer
Total Real Power (W) in a balanced 3-phase system is P = √3 × Line Voltage × Line Current × Power Factor.
涓夌浉闆诲姏 瑷堢畻銉勩兗銉?
涓夌浉闆绘皸銈枫偣銉嗐儬銇窔闁撻浕鍦с€佺浉闆诲湩銆佺窔闆绘祦銆佺浉闆绘祦銆侀浕鍔涖倰瑷堢畻銇椼伨銇欍€?
銈广偪銉?Y)绲愮窔
- *V绶氶枔 = sqrt(3) x V鐩?
- *I绶?= I鐩?
- P = sqrt(3) x V绶氶枔 x I绶?x cos(phi)
銉囥儷銈跨祼绶?
- *V绶氶枔 = V鐩?
- *I绶?= sqrt(3) x I鐩?
闁㈤€ｃ儎銉笺儷
- *銈兗銉犮伄娉曞墖瑷堢畻銉勩兗銉?
- 銉偆銉ゃ兗銈点偆銈鸿▓绠椼儎銉笺儷
Design Notes
Three-phase systems are standard in industrial motor drives and high-power distribution because they provide constant power transfer (zero torque ripple on motors) and require less copper wire than equivalent single-phase systems. When switching between Wye (Star) and Delta configurations, remember that in Wye, Line Current = Phase Current but Line Voltage = √3 × Phase Voltage. In Delta, it's reversed. Always ensure your power factor (PF) is as close to 1.0 as possible to minimize reactive power losses.
Common Mistakes
- 1
Using Phase Voltage instead of Line-to-Line Voltage when applying the √3 factor.
- 2
Forgetting to multiply by the Power Factor, yielding Apparent Power (VA) instead of True Power (Watts).
- 3
Assuming an unbalanced load calculation can use this simple balanced formula.
Engineering Handbox
1. Identify variables: VL = 480, IL = 25, PF = 0.85 2. Multiply: 1.732 × 480 × 25 × 0.85 3. Result: 17,666.4 Watts
Knowledge Base
三相電力の公式は？
P = √3 × V線間 × I線 × cosφ。平衡負荷のスター・デルタ両方に適用。
スター結線とデルタ結線の違いは？
スター：V線間 = √3×V相、I線 = I相。デルタ：V線間 = V相、I線 = √3×I相。
力率とは？
PF = 有効電力/皮相電力 = cosφ。PF=1.0は純抵抗負荷。モーター：0.75〜0.90。
三相が単相より効率的な理由は？
瞬時電力が一定で、トルクリプルなし。同じ電力で銅使用量が約25%削減。
VFD（インバータ）とは？
可変速駆動装置。AC→可変周波数三相ACに変換しモーター速度を制御。省エネ20〜50%。