三相电机的某些实测特性曲线

三相电机参数：

0.75KW，额定电流是2A，功率因数0.71，效率78.9%。制式S1.

1.负载不变时的线电压与线电流的关系

1.1相关数据与python代码：

'''
这里记录了一系列的实验：
第一组实验：近乎空载，改变电机的输入电压，查看电流的变化
第二组实验，增大负载（带动电机，励磁电流为0.50A），改变输入电压，查看电流的变化
第三组实验，增大负载（带动电机，励磁电流为0.90A），改变输入电压，查看电流的变化

'''
import matplotlib.pyplot as plt

curr_noload_50Hz = {"360":11.63, "370":12.06, "380":12.59, "390":13.12,"400":13.69, "410":14.38};
curr_500mAload_50Hz = {"360":11.91, "370":12.33, "380":12.76, "390":13.30,"400":13.90, "410":14.45};
curr_900mAload_50Hz = {"360":12.93, "370":13.33, "380":13.68, "390":14.12,"400":14.62, "410":15.18};

# 数据
freqs = ["360", "370", "380", "390", "400", "410"]
curr_noload = [11.63, 12.06, 12.59, 13.12, 13.69, 14.38]
curr_500mA = [11.91, 12.33, 12.76, 13.30, 13.90, 14.45]
curr_900mA = [12.93, 13.33, 13.68, 14.12, 14.62, 15.18]

curr_noload = [curr * 0.1 for curr in curr_noload]
curr_500mA = [curr * 0.1 for curr in curr_500mA]
curr_900mA = [curr * 0.1 for curr in curr_900mA]

# 绘制线图
plt.plot(freqs, curr_noload, label="curr_noload")
plt.plot(freqs, curr_500mA, label="curr_500mA")
plt.plot(freqs, curr_900mA, label="curr_900mA")

# 图的标题和坐标轴标签
plt.title("Current vs. Voltage of 3Phase-engine")
plt.xlabel("Voltage")
plt.ylabel("Current (A)")

# 图例
plt.legend()

# 显示图像
plt.show()

 2.负载不同的输入电流源曲线：

2.1 数据与代码

import matplotlib.pyplot as plt
import numpy as np

#第一组实验，电压固定为380V，改变负载电机的励磁电流，记录电动机电流变化
curr_withfixVoltage = {"0": 12.41, "0.22":12.44, "0.47":12.69, "0.68": 13.06, "0.85":13.42,"0.90":13.65, "1.08":14.22,"1.13":14.46}
#第二组实验，电压固定为380V，改变负载电机的励磁电流，查看发电机电流变化
curr_ofLoad = {"0": 0.002, "0.22":0.449, "0.47":1.102, "0.68": 1.668, "0.85":2.10,"0.90":2.23, "1.08":2.63, "1.13":2.75}
# 数据
loadInCurr = [float(key) for key in curr_withfixVoltage.keys()] #电动机负载的励磁电流
currOfEngine = [item for item in curr_withfixVoltage.values()] #电动机随励磁电流的变化，输入电流
curr_ofLoad1 = [item for item in curr_ofLoad.values()] #负载电动机的输出电流

powerofcurr_ofLoad = [(item*item) for item in curr_ofLoad.values()] #负载电动机输出电流的平方=功率
currOfEngine_shift = [(item-12.41)*5 for item in curr_withfixVoltage.values()] #电动机输入电流的增量，并放大
currOfEngine_sqrt = [np.sqrt((item-12.41)*5) for item in curr_withfixVoltage.values()] #电动机输入电流的增量，开平方

# 绘制线图
plt.plot(loadInCurr, currOfEngine, label="engineCurrRaw")
plt.plot(loadInCurr, currOfEngine_shift ,label="engineCurr_shifted_zoomed")
plt.plot(loadInCurr, currOfEngine_sqrt ,label="engineCurr_SqrtedOf(shifted_zoomed)")
plt.plot(loadInCurr, curr_ofLoad1,label="loadCurrRaw")
plt.plot(loadInCurr, powerofcurr_ofLoad ,label="loadCurr^2")
print(powerofcurr_ofLoad)

# 图的标题和坐标轴标签
plt.title("Current of Engine vs. Load")
plt.xlabel("load in current scale.")
plt.ylabel("Current(A) of Engine")

# 图例
plt.legend()

# 显示图像
plt.show()

3.结论

假若需要使用线电流的值来预测输出功率。

1.假定外部电压一定，则线性度更好的指标是：输入线电流与空载电流之差的sqrt.

4.现实数据校验

1.空载电流如果为100，负载电流记作200，那么2倍负载电流应该为：
        ((20-0)/(10-0)) * sqrt(200-100))^2 + 100 = 500

2.空载电流如果为110，负载电流记作200，那么2倍负载电流应该为:

        ((20-0)/(10-0)) * sqrt(200-110))^2  + 110 = 360 + 110 = 470

3.空载电流如果为114，负载电流记作200，那么2倍负载电流应该为:

        ((20-0)/(10-0)) * sqrt(200-114))^2  + 114 = 344 + 114 = 458

4.空载电流如果为114，负载电流记作200，那么2倍负载电流应该为:

        ((20-0)/(10-0)) * sqrt(200-116.5))^2  + 116.5 = 334 + 116.5 = 450.5