三相功率计算器
在功率、电流、电压和功率因数之间换算。
尝试一个工程 5
每项工作都会预填示例数值。请替换为您自己的数值。
- Convert amps to three phase powerThe kW and kVA of a 63 A three phase load at 400 V.
- Find kW from a clamp readingThe kW of 100 A at 0.8 power factor.
- Find the kVA of a single‑phase loadThe kVA of 40 A at 230 V.
- Find the reactive power of a loadThe kvar of 50 A at 0.7 power factor.
- Turn a meter reading into kWThe kW from a metered current and power factor.
输入
使用默认输入值的示例计算。
- 相
- 三相
- 电压
- 400 V
- 电流
- 50 A
- 功率因数
- 0.9
视在功率
34.64kVA
- 有功功率
- 31.18kW
- 无功功率
- 15.1kvar
此结果仅供设计参考。请对照现行标准进行核验。
计算步骤
- 视在功率结果34.64kVA
- 有功功率31.18kW
- 无功功率15.1kvar
关于此计算器
How this is calculated
The tool converts between current, apparent power, real power and reactive power. It works on one phase or on three. It does not read a standard. The method is the power triangle.
- Inputs. You pick one phase or three. You enter the voltage, the current and the power factor. On three phases the voltage is the line voltage.
- Apparent power. On three phases, S = √3 × V × I ÷ 1000. On one phase, S = V × I ÷ 1000. The result is in kVA.
- Real power. P = S × power factor. The result is in kW.
- Reactive power. Q = √(S² − P²). The result is in kvar.
Enter the line voltage on three phases, such as 400 V. Enter the phase voltage on one phase, such as 230 V.
Worked example
- 50 A at 400 V on three phases, power factor 0.9. The apparent power is 34.64 kVA. The real power is 31.18 kW. The reactive power is 15.1 kvar.
Limits
The tool assumes a balanced load. It assumes a sine wave. A load with harmonics needs a true RMS reading. The tool does not size a cable or a device. Use the cable size calculator for that. A motor has efficiency as well as power factor. Use the motor tool for its full load current.
Use the tool to check a meter reading, a motor plate or a supply request. For a load in kW, the full load current tool works the other way. A low power factor raises the kVA for the same kW. The power factor correction tool finds the capacitor size.
See also: kVA to amps at 400 V, Current and power factor to kW and Power factor and reactive power.
问题
结果仅供设计参考。请依据现行标准核对。
三相功率计算器有什么作用？
工具将电压、电流和功率因数换算为视在功率、有功功率和无功功率。可用于单相或三相。三相结果使用根号三和线电压。
哪些输入最重要？
电压和电流决定视在功率。功率因数将视在功率分解为有功功率和无功功率。功率因数为 1 时无无功功率。三相时请输入线电压，而非相对中性线的电压。
常见的注意事项有哪些？
工具仅由幅值计算无功功率，因此不显示负荷为超前还是滞后。结果假定三相负荷相等且平衡。输入值保存在页面地址中，因此链接可重现相同的换算。
计算示例
- Ohm's law on a 3 kW water heater elementWork the current and working resistance of a 3 kW, 230 V water heater element with Ohm's law, why a cold meter reading is lower, then a 9 kW three‑phase bank.
- Three‑phase power: kVA to amps at 400 VThe root three relation between amps, kVA and kW on a 400 V board, worked at 50 A and a 0.9 power factor, with the kvar figure the engine returns.
背景
- Ohm's law and power on d.c. and a.c.Ohm's law and the power formulas on d.c., single‑phase and three‑phase a.c.: how power factor and impedance change them, and how any two values give the rest.
- Maximum demand and diversityWhy consumer mains are smaller than the sum of the loads. The four methods of Cl 2.2.2, the Table C1 groups, and a house that lands on 70.18 A.
- Power factor and reactive powerWhat power factor is, why a low one costs current and capacity, how a capacitor bank corrects it in steps, and when harmonics call for a detuned bank.
- Harmonics and neutral sizingWhy third harmonic current adds in the neutral of a four‑wire circuit, what the 0.86 factor does, and how to apply it by hand to a cable size result.
相关工具
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