Main Sector of relevance\IRC classification 8. Industrial Manufacturing, Material and Transport Technologies
8.33 Electrotechnical powder materials on the basis of copper, nickel and wolframium
Developers’ contact information
State Scientific Institution “The Powder Metallurgy Institute of the National Academy of Sciences of Belarus”
41 Platonov Street, Minsk BY-220005
Summary
The electrotechnical powder materials on the basis of copper, nickel and wolframium have been elaborated for being used as electrical contacts ensuring closing and opening line circuits in heavy-current commutating devices and machinery (trolleybuses, metro, electrical trains, power trucks, cranes, transformer and rectifying devices, circuit breakers for moto machinery, voltage distributors, magnetoigniters, electrodes-current leads for contact welding, etc.). The technological processes for producing electrical contacts of various shape and purpose are mastered at pilot-plant production of the Institute of Metal Powder Industry (National Academy of Sciences of Belarus); this allows avoiding importing costly contacts.
Description
Modern power-consuming machinery, e. g. electric transport, distributing transformers, etc. are equipped with devices possessing breaking electrical contacts. The distinctive feature of the conditions in which these contact pairs work is the contacts response at high frequency, greater switched current capacity and significant impact loads. Thus, silver or silver-based alloys and pseudoalloys are the materials for making this class of contacts. Since silver is an expensive precious metal that is not mined on the territory of the Republic of Belarus, the shortage of these electrical contacts has been witnessed. The studies of the Institute of Metal Powder Industry showed that electrical contacts made of silver can be replaced by those made of copper-based composite materials, high-melting metals (e.g. wolfram, molybdenum with alloying elements), and rare-earth metals with low electrons output work. Developing and manufacturing of these contacts allows substituting silver-bearing contacts, end their shortage in production industry and avoiding probable procurement from abroad as well as reducing their cost. Experience acquired by now proved that the developed powder copper-wolframium composite materials for electrical contacts can be widely used for electric transport, in production industry for closing and opening line circuits with high rate of operations, considerable impact loads on contacts, high switched current capacity. Besides, the developed powder materials of copper and wolframium-based electrical contacts allow minimizing silver consumption and reducing costs of electrical contacts. The approximate cost of contacts can be reduced by 20–30% as compared to import-based purchases. Modern moto machinery is supplied with varied electrical equipment having electric contact-breakers – e. g. horns, magnetoigniters, voltage regulators, etc. The distinctive operation feature of such devices is a long sequence of switching operations at enhanced currents and voltages when a pure wolframium contact serves as an electric breaker. The technology of making contacts from pure wolframium makes provision for the operations of heat treatment at 3000-3200 °C, rotary hammering and hot extrusion or cogging that require complicated and expensive equipment to be used for their realization. The studies carried out by the Institute of Metal Powder Industry showed that wolframium contacts can be replaced by ones produced applying powder metallurgy methods from composite materials on the basis of wolframium alloyed with additives of copper, nickel and other elements. These additives can enable to activate sintering process and obtain inexpensive high-density composite contacts that are as good as pure wolframium ones as far as their properties are concerned. Experience acquired by now proved that the developed powder wolframium-based composite material for electrical breakers contacts can be widely used for cars, motorbikes, diesel and electrical trains, in production industry for closing and opening line circuits with high rate of operations, considerable impact loads on contacts, high voltages.
Technology type
Technical advantages and economic benefits
Designation: switching of heavy currents in a variety of devices
and mechanisms.
Scope of application: different types of contacts for electrical switching
devices: particularly, high-voltage circuit breakers, arcing contacts, main
contacts, high-voltage vacuum circuit breakers, coils current regulators of
high-power transformers, disconnecting switches, eliminators, low-voltage heavy
and medium duty bladed switches, interchanging switches, contactors, starters,
controllers, etc.
Advantages as compared to equivalents: high reliability of operation and long
service period without repairs and replacement; possibility of contacts
regeneration.
Technology differentiation and uniqueness
Ensures possibility of replacing silver-bearing electrical
contacts for cheaper and less scares copper-wolframium materials.
Electrical contacts materials are protected by two patents of the Republic of
Belarus.
Context in which technology was identified
IX, X, XI International Specialized Exhibitions “Powder Metallurgy – 2003, 2005, 2007”.
Technological keywords
Electrical contact, switching, current, voltage, copper, wolframium, nickel.
Development Stage
Intellectual property rights
Range of applications
Power industry.
Classifier Used at the EU Innovation Relay Centres
Preferable Regions
Practical experience
The developed powder materials and technologies for making
electrical contacts have been successfully probe-tested:
Environmental impact
None.
Type of collaboration sought
Terms and restrictions
None.
Available technical assistance