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Redox-based resistive switching devices can be switched between a high resistance state and a low resistance state in a reversible manner. An important requirement is the stable operation between these two states for a high amount of switching cycles. In this work the switching dynamics of these devices are investigated by means of device simulation. Hereby, we discuss the conditions for which a fading...
Conductive adhesive became solid at low temperature compared with Pb/Sn solder melting point. It was used as micro-interconnection material for those temperature sensitive components. In this paper, experiments were conducted to characterize conductive adhesive joints at microwave frequency. A microwave switch was attached on aluminum substrate by conductive adhesive. The tests on shear force and...
The performance envelope, i.e. energy vs. frequency, of adiabatic logic circuits based on nanoelectromechanical (NEM) switching elements will be explored. It will be shown that the contact resistance and the mechanical commutation time of the NEM switches dictate the performance envelope of such circuits. Approximate analytical expressions will be derived based on a reduced order model (ROM) of the...
Laterally actuated nanoelectromechanical relays with compliant source-drain contacts are presented. The relay sidewalls are coated with a 30 nm-thick conductive layer of titanium nitride (TiN) deposited using atomic layer deposition (ALD). By hollowing the tip of the relay, a flexible sidewall is formed from the thin TiN that results in a larger contact area and therefore improves the contact properties...
On Load Tap Changer (OLTC) failure occurs is due to the insulation degradation and contacts failure inside it. Other than that, contacts wear influences the OLTC performances. The worn contacts will cause hotspots in the OLTC tank and cause the insulating oil to degrade faster. As a result, this will lead to the damage of complete transformer unit. Thus, the research work that has been carried out...
This paper presents the design and measurements of a miniature RF MEMS (Micro-Electro-Mechanical System) metal-contact switch. The dimensions (25×24×1.6 µm) and shape of the beam and actuation pad have been optimized to result in a 12–25 µN contact force at 52–60 V actuation, with a corresponding restoring force of 15 µN. Measured S-parameters on a single switch show an up-state capacitance of 5 fF...
Resistance measurements on power transformers are a widely accepted method for finding winding defects. Continuity of the tap changer contacts can also be checked when the on-load tap changer (OLTC) is operated during the resistance measurement. Resistance measurements that also record the resistance during OLTC operation are called dynamic resistance measurements. This off-line diagnostic method...
The paper outlines the manufacturing technology of different silver-metal and silver-metal oxide composite materials to be used in contacts of low-voltage switches. There were conducted tests of the electrical properties of contacts made of eight different composite materials and hard silver. There was determined their resistance to arc erosion and static welding. There were also measured changes...
This paper discusses the recently developed analysis method for service aged power transformers equipped with an OLTC: dynamic resistance measurements (DRM). Because the on-load tap changer contributes to many power transformer failures the emphasis is on OLTC diagnosis. Off-line diagnosis of on-load tap changers during regular maintenance can detect maintenance errors and assess the condition of...
This paper reports on the reliability issues encountered during the development of a dry ohmic switch fabricated in MEMS technology. Particularly, focus is made on electrical contact reliability. Contact degradation during hot switching tests has been noticed, and leads to switch lifetime limitation. In order to understand this phenomenon, characterizations have been performed on damaged switches...
A persistent current switch (PCS) is used for superconducting applications, such as superconducting magnetic energy storage (SMES) system. The authors have proposed a mechanical switch of Y-Ba-Cu-O (YBCO) bulk as a mechanical PCS. In previous study, in order to investigate the contact characteristics of the switch, 50A current tests were performed and the contact resistance between two YBCO contacts...
Test switches used in protective relay schemes are selected based on quality, price and convenience features. The criteria selection assumes all the switches perform the basic functions they are intended to perform. This paper questions that basic assumption and performs an evaluation of existing offerings, and analyzes the impact of their performance in the power system.
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