Medium voltage vacuum circuit breaker with per phase electromagnetic actuator

In medium voltage vacuum circuit breakers, in order to achieve an even distribution of force along the entire length of the drive shaft, the drive mechanism is made per phase, that is, a separate electromagnet is installed under each pole. The analysis of designs and features of operation of vacuum circuit breakers with a per phase electromagnetic drive is carried out. Deficiencies in the designs of these drives have been identified. The design of a vacuum circuit breaker with a per phase electromagnetic drive and a kinematic diagram of the operation of a vacuum circuit breaker with a monostable polarized electromagnet and a return spring during the closing operation are considered. As a per phase drive, it is proposed to use three monostable polarized electromagnets with return springs, which makes it possible to reduce the overall dimensions of not only the drive electromagnet, but also the vacuum circuit breaker. Moreover, the return spring is not included in the design of the proposed electromagnet, but is part of the circuit breaker drive mechanism. The design of the housing of the vacuum circuit breaker with a per phase drive and a synchronizing shaft has been developed, which makes it impossible for the non-simultaneous closing and opening of the main contacts when performing switching operations. The calculation of a monostable polarized electromagnet is carried out and the possibility of its use as a per-phase drive in a medium voltage vacuum circuit breaker is confirmed.

Actuating a Magnetic Shape Memory Element Locally with a Set of Coils

The local actuation of a magnetic shape memory (MSM) element as used in an MSM micropump is considered. This paper presents the difference between an electromagnetic driver and a driver that uses a rotating permanent magnet. For the magnetic field energy of the permanent magnetic drive, the element takes in a significant stray field. In a particular case, energy reduction was 12.7 mJ. For an electromagnetic drive with an identical size of the MSM element, the total magnetic field energy created by the system was 2.28 mJ. Attempts to experimentally nucleate twins in an MSM element by energizing an electromagnetic drive failed even though the local magnetic field exceeded the magnetic switching field. The energy variation is an order of magnitude smaller for the electromagnetic drive, and it does not generate the necessary driving force. It was assumed in previous work that the so-called magnetic switching field presents a sufficient requirement to nucleate a twin and, thus, to locally actuate an MSM element. Here, we show that the total magnetic field energy available to the MSM element presents another requirement.

Mathematical modeling of the equivalent electric circuit of the electromagnetic drive of a high-voltage circuit breaker and its computer simulation in the Statistica software

Магнитные системы могут быть представлены в виде электрических цепей, поскольку закономерности и уравнения, описывающие процессы в проводниках магнитных и электрических величин, во многом идентичны. Это связано с близкой природой этих явлений. При этом переход к эквивалентной электрической схеме позволяет производить модельные эксперименты с меньшей затратой вычислительных ресурсов. Воспользовавшись электрической схемой замещения электромагнитного привода высоковольтного выключателя, произведен эксперимент, результаты которого проанализированы методами математической статистики, благодаря чему получены регрессионное уравнение. На основе этого уравнения можно рассчитывать магнитодвижущую силу, возникающую в подвижном якоре электромагнитного привода.

Correction of Young’s Modulus Calculation in the Flexural Mode of Resonant Column Test

The resonant column test includes torsional and flexural modes that can be used to obtain reduction curves for the shear modulus and Young’s modulus of the soil, respectively. When the resonant column test is performed under flexural mode, Young’s modulus is calculated mainly using the measured resonant frequency following the formula proposed by Cascante et al. However, this formula does not consider the rotational inertia effect of the electromagnetic drive disk of the resonant column apparatus and thus may inaccurately calculate Young’s modulus. In this study, the formula was modified by considering the rotational inertia effect of the electromagnetic drive disk, and its accuracy was verified by using three aluminum calibration rods with different diameters as a dummy specimen for the resonant tests in flexural and torsional modes.

Study on Characteristics of Electromagnetic Coil Used in MEMS Safety and Arming Device

Traditional silicon-based micro-electro-mechanical system (MEMS) safety and arming devices, such as electro-thermal and electrostatically driven MEMS safety and arming devices, experience problems of high insecurity and require high voltage drive. For the current electromagnetic drive mode, the electromagnetic drive device is too large to be integrated. In order to address this problem, we present a new micro electromagnetically driven MEMS safety and arming device, in which the electromagnetic coil is small in size, with a large electromagnetic force. We firstly designed and calculated the geometric structure of the electromagnetic coil, and analyzed the model using COMSOL multiphysics field simulation software. The resulting error between the theoretical calculation and the simulation of the mechanical and electrical properties of the electromagnetic coil was less than 2% under the same size. We then carried out a parametric simulation of the electromagnetic coil, and combined it with the actual processing capacity to obtain the optimized structure of the electromagnetic coil. Finally, the electromagnetic coil was processed by deep silicon etching and the MEMS casting process. The actual electromagnetic force of the electromagnetic coil was measured on a micro-mechanical test system, compared with the simulation, and the comparison results were analyzed.

CONDUCTING FIELD TESTS OF A PROTOTYPE OF A WATER ELECTROMAGNETIC PULSED NON-EXPLOSIVE SEISMIC SOURCE ON A NATURAL RESERVOIR

The article presents the quantitative and qualitative characteristics of a prototype of a seismic non-explosive source with an electromagnetic drive and an assessment of the possibilities of its use during geophysical exploration for oil and gas with increased environmental requirements.