轴电流，是高压电机、发电机、变频电机等类型电机比较常见的问题之一，轴电流较大时，会导致电机的轴承系统发生崩溃，甚至波及到电机绕组，因而，轴电流的控制，是电机生产厂家乃至电机使用者共同关切的问题。

 

有网友提出，他检测到了轴电压，问是否可以测出轴电流？轴电压是否会危害到电机的轴承系统等问题，针对该问题，我们与大家进行一个简单交流。

 

从电流形成的原理分析，轴电压和闭合回路，是产生轴电流的必要条件，轴电流的规避措施，就是围绕切断回路或旁路的两个思路展开。

 

如果在电机的设计和制造过程中，采用了诸如绝缘轴承、绝缘端盖、绝缘轴承套等断路措施，尽管轴电压存在，因为没有能形成闭合回路，自然也就不会产生轴电流。

 

如果是采用旁路措施，即，通过接地碳刷，将轴电流的走向进行引导，既可大大减小轴电流的大小，自然也就解决了轴电流对轴承的危害问题。

 

轴电流监测装置采用高性能单片机为核心控制部件构成控制器，采用空心环形互感器为轴电流传感器，监测电机轴电流变化。单片机实时监测轴电流传感器的变化值，该数值与大轴电流呈线性变化关系，经滤波、数值变换处理后，确认轴电流超过整定值后，轴电流监测装置输出二级报警信号。装置通过参数整定、实时显示具体的电流大小。

Shaft current is one of the common problems in high-voltage motors, generators, variable frequency motors, and other types of motors. When the shaft current is high, it can cause the bearing system of the motor to collapse, even affecting the motor winding. Therefore, the control of shaft current is a common concern for motor manufacturers and even users.
A netizen suggested that he detected the shaft voltage and asked if it is possible to measure the shaft current? We will have a brief discussion on whether shaft voltage will harm the bearing system of the motor and other related issues.
From the analysis of the principle of current formation, shaft voltage and closed circuit are necessary conditions for generating shaft current. The measures to avoid shaft current are based on two ideas: cutting off the circuit or bypassing it.
If circuit breaking measures such as insulated bearings, insulated end caps, and insulated bearing sleeves are used in the design and manufacturing process of the motor, even if the shaft voltage exists, because no closed circuit can be formed, the shaft current will naturally not be generated.
If a bypass measure is adopted, that is, guiding the direction of shaft current through grounded carbon brushes, it can greatly reduce the magnitude of shaft current and naturally solve the problem of shaft current harm to bearings.
We are now discussing another issue, which is raised by the netizen. When the shaft voltage is high, it will pose a threat to the quality and performance of bearings. Therefore, necessary measures need to be taken when the shaft voltage is high! According to the accumulation and statistics of data from different motor manufacturers, when the shaft voltage generated by the motor does not exceed 350mV, it does not have a significant impact on the bearing system of the motor. Otherwise, corresponding avoidance measures must be taken.
Finally, let's talk about the detection of shaft voltage and shaft current. Relatively speaking, the detection of shaft voltage is relatively simple, and can be detected using a millivolt meter with appropriate accuracy. However, due to the irregularity of the shaft current passing through the channel, the collection of shaft current is relatively difficult, and specialized detection equipment is needed for detection.
The shaft current monitoring device adopts a high-performance microcontroller as the core control component to form a controller, and a hollow ring transformer as the shaft current sensor to monitor the changes in motor shaft current. The microcontroller monitors the real-time change value of the shaft current sensor, which is linearly related to the large shaft current. After filtering and numerical transformation, it is confirmed that the shaft current exceeds the set value. The shaft current monitoring device outputs a second level alarm signal. The device displays the specific current size in real-time through parameter tuning.