作为一名优秀的翻译请你用正式的表达用英语翻译以下公司宣传内容注意语言的简洁性和正确性和正式性并按照原文格式进行排版。手把手教你进行轴电压测试 汽车电驱系统的四高化发展高压、高功率、高频、高转速使得共模电压变得更高加载到轴承两端的轴电压也随之增大加大轴承电腐蚀风险。因此为了保证电机的安全运行需要一种科学有效的测试方法对电机的轴电压进行测试。测试完成后还需要对测试结果进行分析和评估确定轴电压是否在安全

Step-by-step guide to axial voltage testing

The development of automotive electric drive systems with high voltage, high power, high frequency, and high speed characteristics has led to an increase in common mode voltage and axial voltage applied to the bearing ends, increasing the risk of bearing corrosion. Therefore, in order to ensure the safe operation of the motor, a scientifically effective testing method is needed to test the axial voltage of the motor. After the testing is completed, the test results need to be analyzed and evaluated to determine whether the axial voltage is within a safe range and what preventive measures should be taken. This article will focus on how to perform axial voltage testing on new energy motors and how to analyze the test data.

NO.1 Motor wiring configuration

1. First, ensure that the test motor/test bench is well grounded. It is recommended to have a single-point grounding system to reduce potential differences between different grounding points that may cause testing interference.

2. Use a flexible low-friction conductive probe to make contact with the motor shaft (the contact point can be the shaft end or the circumference of the motor shaft) to extract the axial signal, and connect it to the signal end of the oscilloscope test probe. The ground clip of the oscilloscope test probe should be connected to the motor casing.

Note: When extracting the axial signal wire, the probe or its lead wire should be insulated from the motor casing. If using the H&G Technology standard test probe (product model: VGS-M10-1; patent number: ZL202221574986X) as shown in Figure 1, a suitable M10x1.5 threaded hole can be opened at a suitable position on the motor casing for installing and fixing the test probe. If the motor casing at the shaft end can be opened, auxiliary fixtures such as magnetic bases can be used to hold and fix the probe.

Figure 1 - H&G test probe VGS-M10-1

3. If the motor is an oil-cooled motor and there is a possibility of oil leakage at the opening, the PTFE thread seal tape can be wound around the appropriate position of the test probe and twisted to the required position to ensure good contact between the conductive fiber and the motor shaft.

4. After the wiring connection shown in Figure 2 is completed, measure the resistance between the casing connection wire and the shaft connection wire with a multimeter when the motor is static to verify that the resistance value is less than 5 ohms. (This requirement does not apply to single motors with insulated bearings on both ends)

Oscilloscope: Recommended bandwidth ≥ 100M, with statistical function is better Measurement mode: Sampling Measurement parameters: Voltage waveform, voltage peak-to-peak value When reading the values, pay attention to the range setting of the signal probe

Figure 2 - Wiring configuration schematic

5. It is recommended to set up wiring on both ends of the motor, and use a dual-channel or multi-channel oscilloscope to measure the axial voltage at the front and rear ends of the motor at the same time to improve testing efficiency.

NO.2 Axial voltage detection

1. It is recommended to measure the axial voltage to ground at the front end of the motor, the axial voltage to ground at the rear end of the motor, and the voltage difference between the front and rear ends of the shaft under different speed and torque conditions, and record the axial voltage waveform and peak-to-peak value (Vpp). In addition, it is also recommended to measure the axial voltage under acceleration and deceleration conditions.

Note: Table 1 is for illustration purposes only. Customers can adjust it according to their own motor technical parameters and operating conditions.

Table 1 - Example of condition matrix

2. When measuring the axial voltage, adjust the vertical knob in a timely manner to ensure that the axial voltage waveform falls within the range of the oscilloscope screen and adjust the horizontal knob to clearly display the axial voltage waveform (usually between 50-500uS).

3. There are usually three typical waveforms of axial voltage, or a combination of two or even three of them.

- Resistive discharge waveform: Usually occurs when the bearing has not established a continuous oil film at low speeds and high loads, or when the bearing is significantly worn after long-term use. - Non-discharge waveform: Usually occurs when the bearing oil film is good at high speeds and low loads, indicating that the oil film can withstand the axial voltage without obvious discharge phenomena. In this waveform, the lower the measured data, the better. - Capacitive breakdown discharge waveform: A certain oil film is formed inside the bearing, but the thickness of the oil film is not enough to withstand the axial voltage, resulting in discharge breakdown. In this waveform, the higher the voltage, the better the quality of the oil film.

NO.3 Data analysis, judgment, and recommendations

1. After the axial voltage testing is completed without taking any preventive measures against bearing corrosion, analyze the recorded conditions (axial voltage waveform chart under the matrix) and the axial voltage Vpp. If the axial voltage waveform shows a non-discharge state under most operating conditions, it indicates that the bearing oil film is in good condition and can withstand the axial voltage without breakdown. In this case, limited preventive measures may be taken or even no preventive measures against axial voltage. If the axial voltage waveform shows a capacitive breakdown state under most operating conditions and the axial voltage peak-to-peak value is generally greater than 15V, it is recommended to adopt a form of discharge to prevent corrosion caused by the axial voltage. If the axial voltage waveform shows resistive discharge or capacitive breakdown discharge but the axial voltage peak-to-peak value is generally less than 10V, it is recommended to use a combination of conductive ring discharge and insulated bearings to prevent corrosion caused by the axial voltage.

2. After taking preventive measures against bearing corrosion, repeat the axial voltage testing under the set condition matrix according to the above axial voltage testing method, record the axial voltage waveform and axial voltage peak-to-peak value, and compare them with the axial voltage without preventive measures. The greater the reduction in the axial voltage peak-to-peak value, the better, and it is recommended that the reduction rate should not be less than 60%.

Share to