ELECTRICAL CONTACT POINT PARTS
Nippon Tungsten is selling electrical contact point parts as a
trade name, ELECTRO-METAL,"EM".
The electrical contact point parts include weak electrical switches
for turning ON and OFF at low voltage and small current and strong
electrical switches for breaking a circuit at ultrahigh voltage and
large current. Furthermore, they include those used under various
conditions such as in air, oil, various gases, and vacuum. We are
producing many kinds of EM products according to the applications
of various switches.
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EM-C
EM-C is a composite alloy of copper and tungsten produced by powder
metallurgy, containing from 10 to 70 weight percent of copper. This
product is usually used for contact points of switches and circuit
breakers filled with oil or SF6 gas.
EM-S
EM-S is a composite alloy of silver and tungsten produced by powder
metallurgy, containing from 20 to 70 weight percent of silver. This
is usually used for contact points of switches and circuit breakers
filled with oil or SF6 gas. This product has good reputation as
arcing contact point materials for circuit breakers, molded-case
circuit breakers (MCCB) for intermediate loads and as contact
points of materials for electromagnetic circuit breakers.
EM-HS
EM-HS is a composite alloy of silver and tungsten carbide produced
by powder metallurgy. The tungsten carbide is a very hard material
to be used for raw materials of cemented carbide, normally
containing from 40 to 70 weight percent of silver. EM-HS is used
more often for contact points of molded-case circuit breaker and
electromagnetic switches because it has more stable contact
resistance than EM-S. EM-HD, whose contact resistance is decreased
and seizure resistance is improved, has a good reputation as fixed
contact points for molded-case circuit breakers.
EM-N
EM-N is a composite alloy of silver and nickel produced by powder
metallurgy, containing from 60 to 90 weight percent of silver as a
standard. Because of high mechanical strength, this product is
often used for main contact points of air circuit breakers having
arcing contacts. In the case of molded-case circuit breakers, this
product is used in combination with EM-GS.
EM-GS
EM-GS is a composite alloy of silver and graphite produced by
powder metallurgy, containing from 97 to 99 weight percent of
silver as a standard. EM-GS has many applications as a contact
point not to get hot because of its excellent seizure resistance
and low contact resistance. Furthermore, because it can slide, this
product is effective to prevent from galling on a sliver-plated
surface; theretofore, is used for main contact points of air
circuit breakers whose application is critical due to sliding.
EM-OD
EM-OD is a composite alloy of various oxides produced by an
internal oxidation method. This is a cadmium-free product, used for
contact points of circuit breakers and switches to be used under
intermediate loads.
* Please contact us separately for the products of copper-tungsten
carbide and other materials having different composition.
* Bonded products: Electrical contact point parts are rarely used
individually and usually bonded to a metal base made of copper,
brass or iron. Nippon Tungsten is supplying those products after
directly bonding them by brazing, NDB method and rotary friction
bonding.
