ABB Ltd

About: ABB Ltd is a company organization based out in Zurich, Switzerland. It is known for research contribution in the topics: Voltage & Signal. The organization has 6222 authors who have published 6852 publications receiving 83994 citations.

Electrical resistance element

Abstract: An electrical resistance element having a resistance body between two contact terminals. The resistance body has PTC behavior and is composed of a polymer matrix and a filler component embedded in the polymer matrix. The filler component is composed of electrically conducting particles. Although the element is of simple and inexpensive construction, the resistance element is notable for good electrical conductivity in the low-resistance state and for a low response time for the PTC transition from the low-resistance to the high-resistance state. This is achieved as a result of the fact that at least some of the electrically conducting particles are formed as composite bodies having electrically conducting surfaces and/or as hollow or porous bodies composed of electrically conducting material. These particles have a lower specific density and/or lower specific heat capacity than solidly formed particles composed of conductive material.

Region-oriented charge simulation

Abstract: A new approach for the calculation of electrostatic fields using the charge simulation method is presented. The basic idea is to divide multidielectric arrangements into regions. The field and potential inside a region are calculated by only taking into account the discrete charges that surround it. Interestingly, one can obtain a sparse matrix which may be rapidly solved using standard techniques. The new method has been successfully applied to the calculation of many practical problems in high voltage engineering. >

Method and apparatus for monitoring the fuel and water supply of a gas turbine multiburner system

Abstract: In a method for monitoring the supply system (10) of a gas turbine having a multiburner system, said supply system (10) comprising at least one distribution system (15, 24), via which a pressurized medium required for operating the multiburner system is distributed to a plurality of individual burners (12, . . . , 14) opening into a combustion chamber, reliable detection and analysis of faults is achieved in that, while the gas turbine is operating, the pressure loss in the at least one distribution system (15, 24) is measured continuously, in that the measured pressure loss is compared with a desired value characteristic of the respective operating state of the gas turbine, and in that a communication is issued when the measured pressure loss deviates from the associated desired value by a predetermined value.

High-voltage insulation for stator windings of electric machines

Abstract: The conductor bars of stator windings of rotating electric machines are usually multiply wound around with two-layer mica strips as major insulation and then impregnated with synthetic resin. It is proposed to use as first layer (L1) a mica strip which is provided on both sides with a textile carrier (24, 25). The further layers (L2, L3, L4, . . .) are then wound with a mica strip (27) provided with a textile carrier (28) only on one side. A major insulation constructed in this way is very homogeneous. The textile carrier (24), preferably consisting of glass fabric, which bears directly on the conductor surface, optimizes the impregnation and produces an effective bond between the insulation and conductor.

Ozone production in oxygen by means of F2-laser irradiation at λ=157.6 nm

Abstract: Ozone is generated in pure oxygen (p≦5 kPa), synthetic air (p≦7 kPa) and oxygen-argon mixtures (p≦3 kPa) by irradiation of these gases with the VUV light of a repetitively pulsed (f L≦15 Hz) F2-laser at λ=1576 nm with maximum about 4 mJ/pulse An absorption photometer measurement operating at 2537 nm (Hg line) determines the ozone concentration as a function of oxygen and/or additive gas pressure, the repetition frequency of the laser and the wall temperature of the reaction chamber The temporal development of the ozone concentration as a function of these parameters is calculated by means of rate equations for the species O(3 P), O2(X 3∑ g − ), O3(1 A 1), O(1 D), O2(a 1Δg), O2(b 1∑ g + ) and vibrationally excited O 3 * (1 A 1) and the photon distribution The maximum concentration of O3 in the sealed-off chamber reaches 16% in pure O2, 41% in air and 12% in a 1:5 O2-Ar mixture at 3 kPa The annihilation of O3 by the wall and temperature dependent volume processes (300 K≦T≦395 K) is studied and the experimental and theoretical results are compared