Kabushiki Kaisha Toshiba

Hideyasu Andoh

Hironori Suzuki

Yoshiyasu Itoh

Hiroyoshi Narita

Hiroshi Endo

Iwao Mitsuishi

Fumio Ueno

Motomasa Imai

Naoki Shutoh

Susumu Nishiwaki

Masahiro Hanai

Yoshihiko Hirano

Toshiya Imai

Takahiko Shindo

Nobuyuki Shimizu

Masahiro Kan

Yasuhiko Taniguchi

Shoji Kozuka

Takeshi Udagawa

Yoshikazu Tanno

Yoshihiro Ishizaki

Masahiko Ebina

Keisuke Shimagami

A voltage non-linear resistor unit is composed of at least one of voltage non-linear resistors which is composed of a columnar sintered body formed by molding and sintering a raw material, the sintered body having both end surfaces having a surface roughness in term of arithmetic average surface roughness Ra of 1 to 2 &mgr;m and being formed with an electrode film layer, a terminal metal fitting formed in a predetermined shape and attached to the voltage non-linear resistor, and a soldering material arranged between the voltage non-linear resistors and between joint surfaces of the voltage non-linear resistor and the terminal metal fitting, the joint surfaces being joined by heating the soldering material and applying a load vertically to the joint surfaces while giving a rotation motion thereto. Such voltage non-linear resistor is effectively assembled into an arrester.

Voltage non-linear resistor unit and arrester unit

A sintered body which can be formed into a resistor having a non-linear resistance includes zinc oxide is the principal composition and bismuth, cobalt, antimony, manganese and nickel respectively converted to expressed Bi,O,, Co,O,, Sb,O,, MnO and NiO as auxiliary compositions. The compositions contains 0.05 to 10 mol % of Bi,O,, 0.05 to 10 mol % of Co,O,, 0.05 to 10 mol % of Sb,O,, 0.05 to 10 mol % of MnO and 0.05 to 10 mol % of NiO; the content ratio of the Bi,O,to the NiO is in a mole ratio of 0.5 or more but 1.5 or less, and the content ratio of the MnO to the Sb,O,is in a mole ratio of 1.0 or less. Preferably, the composition contains at least one of 0.5 to 500 ppm of aluminum, converted to Al,, and 10 to 1000 ppm of at least one or the other of boron and silver, converted respectively to B,, and Ag,. The composition may also contain 0.01 to 1000 ppm of at least one of sodium, potassium, chlorine and calcium, converted respectively to Na,, K,, Cl,and Ca,.

Sintered body having non-linear resistance characteristics

A nonlinear resistor is formed by forming side surface insulating layer 2 on a sintered body 1 which contains zinc oxide as a main component and providing a pair of electrodes 3 on upper and lower surfaces of the sintered body 1. The electrodes 3 are formed by plasma thermal spraying of less than 10 kW in an atmosphere in which an oxygen concentration is set to 22 volume % or less. The electrodes 3 are formed of aluminum, copper, zinc, nickel, silver, or their alloy whose average particle size is within 5 .mu.m to 50 .mu.m. Preferably porosity is less than 15%, weight percentage of metal oxide is less than 25%, average film thickness is within 5 .mu.m to 500 .mu.m, average surface roughness is less than 8 .mu.m, and resistivity is less than 15 .mu..OMEGA..multidot.cm. Accordingly, the nonlinear resistor having the excellent discharge withstand can be provided.

Nonlinear resistor with electrodes formed by plasma spraying

According to this invention, there is disclosed a compact power circuit breaker having a large breaking capacity and stable breaking performance due to a compact closing resistor unit having high performance. The power circuit breaker includes a main switching mechanism having an arc extinguishing function, an auxiliary switching mechanism parallelly connected to the main switching mechanism and having an arc extinguishing function, and a closing resistor unit connected in series with the auxiliary switching mechanism and incorporated with a resistor containing zinc oxide (ZnO) as a main component and titanium figured out as titanium oxide (TiO.sub.2) in an amount of 0.5 to 25 mol% and nickel figured out as nickel oxide (NiO) in an amount of 0.5 to 30 mol. % as sub-components.

Power circuit breaker and power resistor

Growing community of inventors

Tokyo, Japan

Hideyasu Andoh