Medium and high voltage contacts
The contact is an essential component of the vacuum interrupter. It is the component that generates and extingutes the arc. As it is in a high-temperature and strong magnetic field environment, the contact materials must meet stringent requirments, including high interrupting capability, high dielectric strength, high welding resistance, low chopping current, and low gas content. Copper-chromium contacts are widely used in vacuum circuit breakers and vacuum switches due to their excellent arc-extinguishing performance and welding resistance.
Low-chromium content contacts by infiltration technology
Our company possesses the only low-chromium contact infiltration technology both domestically and internationally. This technology replaces traditional casting with infiltration, and the composition non-uniformity of all contact product is less than 0.3%. This technology enhances the product's welding resistance and y interrupting capability , thereby greatly extending the service life of the switch.
Product Introduction
1. CuCr (30%-50%) series contacts
The use of this technology significantly enhances the performance and reliability of CuCr 30-50 series contacts. The performance indicators of this seriesexceed mechanical industry standards (JB/T7098-2002 Technical Conditions for Copper-chromium Electrical Contacts) and have advanced to an international leading level.
Types | Chemical Composition （mass%） | Gas Content （mass%） | Contacts performance | Operating environment | ||||
| Cr | Cu | O≤ | N≤ | Density ≥g/cm3 | Hardness ≥HB | Electrical Conductivity ≥MS/m | ||
CuCr30 | 29-32 | balance | 0.035 | 0.003 | 8.25 | 75~110 | 28 | 12KV-24KV |
CuCr40 | 39-42 | balance | 0.035 | 0.003 | 8.10 | 85~110 | 24 | 40.5KV-126KV |
CuCr50 | 49-52 | balance | 0.035 | 0.003 | 8.00 | 85~110 | 20 | 40.5KV-126KV |
2. Copper-tungsten contacts
Types | Density ≥g/cm3 | Hardness ≥HB | Resistivity ≤μΩ·cm |
CuW85 | 15.90 | 240 | 5.7 |
CuW80 | 15.15 | 220 | 5.0 |
CuW75 | 14.50 | 195 | 4.5 |
CuW70 | 13.80 | 175 | 4.1 |
CuW65 | 13.30 | 155 | 3.9 |
CuW60 | 12.75 | 140 | 3.7 |
3. Copper-chromium contacts
This product was first developed and promoted by Professor Wang Yaping. It is the first product on the market capable of addressing the issue of poor welding resistance in copper-chromium contacts. This product can be utilized with vacuum contactors and load switches. It abandons the approach of adding low-melting-point elements to lower interrupting capability. By adding a trace amounts of special high-melting-point composite components, it is possible to reduce the welding strength of the contact's arc fusion zone by more than 50% while maintaining the contact's interrupting capability. It is suitable for vacuum contactors and load switches, as well as the preferred contact for low-energy vacuum circuit breakers. This type of contact was designed to replace the current tungsten-copper and tungsten carbide-copper contacts on the market, and its interrupting performance is greatly enhanced.
4. Integrated copper chromium contacts
A unique forming technology is utilized to manufacture the infiltrated copper-chromium 25-40, copper-chromium 50, and copper-chromium-X contacts that are integrated with the copper base (including the conductive rod). This technique does not employ brazing materials, has no voids at the interface, has a bonding strength more than twice that of brazed interface, and simplifies the user's contact plating and brazing processes. It significantly lowers the loop resistance while enhancing the insulation strength and interrupting capability of the vacuum interrupter. It is ideal for ultra-high voltage vacuum switches.
5. Capacitor Switching Specialized Contacts
Our company has the technique and capability to manufacture high-chromium content copper-chromium alloys with chromium contents of up to 90 wt.%. The Copper-chromium contacts specifically designed for capacitor switching applications have greatly increased voltage withstand capability and post-arc dielectric recovery in vacuum circuit breakers, which are suitable for capacitor switchings and ultra-high voltage vacuum circuit breakers.
Email：smqykj2023@163.com，yang.w@shccig-eu.de
