How to deal with arc erosion of copper chromium contacts?
Cleaning the contact: If there is dirt or oxide layer on the surface of the contact, it can be cleaned with gasoline. The oxide layer of silver contacts has good conductivity and usually does not require treatment; The oxide layer of copper contacts can be smoothed with an oil file or gently scraped off with a small knife.
Adjust contact pressure: Check if there is mechanical damage to the contacts that causes spring deformation and insufficient contact pressure. You can use a piece of paper to measure the pressure on the contact point. The specific method is to clamp a piece of paper between the moving and stationary contact points, and pull the paper by hand. If the paper is easily pulled out, it indicates that the pressure is not enough and the spring should be replaced.
Replace contact: If the contact has fusion welding or severe erosion, it should be replaced. Choosing appliances with a larger capacity can prevent welding caused by insufficient capacity.
Improve working environment: Check the working environment of the contactor to ensure that the contact pressure and overtravel of the contacts are within the specified range. If the contact is poor, the contact situation should be improved, and if necessary, the contact surface should be filed.
Adjust the power supply voltage: Ensure that the power supply voltage is not lower than 85% of the rated value, to avoid insufficient suction and vibration caused by voltage fluctuations or too low, which may cause heating, arcing, or even welding of the main contacts.
How to solve the phenomenon of high current cutoff value in copper chromium contacts?
Optimizing manufacturing process: By using arc melting method, copper chromium contact materials with fine and evenly distributed Cr particles can be obtained. This material has no pores or component segregation, high mechanical strength and density, and is suitable for high-end vacuum circuit breakers and vacuum contactors of 35KV and above levels.
Adjusting the geometric shape of the contact: During the manufacturing process, the cutoff value can be reduced by adjusting the geometric shape of the contact. For example, optimizing the surface treatment and structural design of contacts, reducing surface roughness, ensuring smooth contact surfaces, and thereby reducing the generation and interruption of arcs.
Controlling chromium particle size: Chromium particle size has a significant impact on the current cutoff value of the contact. By controlling the chromium particle size, the electrical performance of the contact can be improved and the current cutoff value can be reduced. Generally, the smaller the chromium particle size and the more evenly distributed it is, the better the performance of the contact.
Using appropriate contact materials: Choosing the right contact material is also key to reducing the current cutoff value. For example, copper chromium contact materials prepared by infiltration or solid-state sintering methods can exhibit good electrical performance and mechanical strength at different voltage levels.
How to deal with the problem of vacuum degree decrease in copper chromium contacts?
Regular inspection and replacement of vacuum interrupter: If the vacuum degree drops significantly, it may be necessary to replace the vacuum interrupter. Regularly check the sealing performance of the vacuum arc extinguishing chamber to ensure that there is no air leakage.
Sealing inspection: Check the sealing performance of the vacuum arc extinguishing chamber to ensure that there is no air leakage. If aging, damage or loose connections are found in the seals, they should be replaced or repaired in a timely manner.
Cleaning and maintenance: Regularly clean the contacts to remove oxide layers and dust. Check and clean all sealing points of the vacuum system, including sealing rings, flange connections, pipeline interfaces, etc., to ensure that they are not leaking.
Adjust the contact pressure of the contacts: Adjust the contact pressure of the contacts to ensure good contact. If the contact is worn and causes poor contact, the contact should be replaced in a timely manner.
Check the vacuum pump: Check the working status of the vacuum pump, including whether the pump oil is contaminated, whether there is dust or foreign matter in the pump, whether the pump body is overheated, etc. If any problems are found, the pump oil should be cleaned or replaced in a timely manner, the accumulated dust or foreign objects inside the pump should be cleaned, and the cooling system of the pump body should be checked for normal operation.
Adjust the heating system: If the heating system generates a large amount of gas or steam that affects the vacuum degree, the heating temperature and heating rate should be adjusted, and the gas emission system should be optimized.