JH JEH电机引接线 春晨电缆

江苏春晨电缆有限公司生产JH JEH电机引接线 春晨电缆，

纯电感不消耗电能，它只与电源不断地进行能量的交换。

Pure inductance does not consume electric energy, it only exchanges energy with power supply continuously.

电感的平均功率为：

The average power of the inductor is:

电感的平均功率计算公式

Calculation formula of average power of inductance

平均功率为零只说明电感不消耗有功功率，并不说明电感中没有功率，电感与电源之间有能量交换，所以瞬时功率并不等于零。瞬时功率的大值即UI的乘积叫做无功功率，用符号QL表示，它反映了电感与电源交换能量的大规模。

If the average power is zero, it only means that the inductor does not consume active power, and it does not mean that there is no power in the inductor, and there is energy exchange between the inductor and the power supply, so the instantaneous power is not equal to zero. The maximum value of instantaneous power, i.e. the product of UI, is called reactive power, which is represented by symbol QL. It reflects the maximum scale of energy exchange between inductance and power supply.

电感无功功率计算公式

Calculation formula of inductive reactive power

工程上的变压器、电动机都是通过电感线圈与电源进行电能和磁能转换而工作的，但由电源提供无功功率，所以无功功率是电感元件工作时要的功率，不能理解为没有用的功率。

In engineering, transformers and motors work by converting electric energy and magnetic energy between inductance coil and power supply, but reactive power must be provided by power supply, so reactive power is the necessary power when inductance element works, which cannot be understood as useless power.

算一算

add up

题：电感线圈的电感L=1H，接到电压为u=220√2 sin（314t+60°）V的电源上，求流过电感的电流i和无功功率QL。

Title: the inductance of the inductance coil is L = 1H, connected to the power supply with the voltage of u = 220 √ 2Sin (314T + 60 °) V, and the current I and reactive power QL flowing through the inductance are calculated.

解：电压的有效值相量为：

Solution: the effective value phasor of voltage is:

相量表示

Phasor representation

计算电感电路

Calculated inductance circuit

电容元件的交流电路

AC circuit of capacitor

如下图所示的交流电路中，电容元件C认为是理想线性元件，其电流、电压的参考方向已标在图中。

In the AC circuit as shown in the figure below, capacitor element C is considered as an ideal linear element, and its reference direction of current and voltage has been marked in the figure.

电容元件的交流电路

AC circuit of capacitor

电流与电压的关系

Relationship between current and voltage

当加在电容两端的电压为u=Umsinωt=U√2sinωt时，并以u为参考量，由前文《电路中的无源元件：电阻、电容和电感》中的下式：JH JEH电机引接线 春晨电缆

When the voltage applied to both ends of the capacitor is u = umsin ω t = u √ 2Sin ω T, and u is taken as the reference quantity, the following formula is given in the previous passive components in the circuit: resistance, capacitance and inductance:

电流电容的关系

Relationship between current and capacitance

可得电容电路的电流为：

The current of the available capacitance circuit is:

电容电路的电流公式

Current formula of capacitor circuit

由上式可见，电容上电流与电压是同频率的正弦量；电流与电压的大小关系为

It can be seen from the above formula that the current and voltage on the capacitor are sinusoidal quantities of the same frequency; the relationship between the current and voltage is