Magnetic circuit

About: Magnetic circuit is a research topic. Over the lifetime, 15707 publications have been published within this topic receiving 118099 citations.

A New Model of Electromechanical Relays for Predicting the Motion and Electromagnetic Dynamics

Abstract: In this paper, a novel multiphysics and nonlinear model for electromechanical relays is presented. The electromagnetic dynamics is analyzed by calculating the total reluctance of the magnetic equivalent circuit (MEC), which is composed of a fixed length iron core and an angular air gap. Magnetic saturation and angular dependency of the reluctance are considered in the analysis. Then, an energy balance over the electromagnetic components of the system is used to obtain the torque which drives the movable armature. A planar mechanism of four rigid bodies, including spring-damping torques that restrict the motion and model the contact bounces that occur in the switchings, is proposed to explain the dynamics of the movable components. Experimental tests show the accuracy of the model in both the electromagnetic and the mechanical parts.

Analysis and Design of Hybrid Excitation Linear Eddy Current Brake

Abstract: This paper presents a novel parallel magnetic path hybrid excitation linear eddy current brake. The eddy current brake using parallel magnetic path scheme with the presence of the PMs, whose flux lines in the primary are oppositely directed with respect to the flux lines by the excitation windings, has the effect of mitigating the saturation of the iron in the teeth of the primary. This allows the brake to be fed with more intense currents improving the braking force. The structure and working principle are introduced. The analytical model was found using the equivalent magnetic circuit method and the layer theory approach. The design method of the eddy current brake was studied using the finite element method. Compared with traditional induction motors and synchronous motors, the design method of the eddy current brake has not been proposed. Therefore, in this paper, the design parameters of the hybrid excitation linear eddy current brake were gradually determined by consulting the design method of the linear induction motor and linear synchronous motor, and a design flowchart was proposed. Finally, a prototype of hybrid excitation linear eddy current brake was created and an experimental study of the eddy current brake was conducted.

Fault indicator providing contact closure and light indication on fault detection

Abstract: A fault indicator for detecting the occurrence of a fault current in a monitored conductor and providing a contact closure and a light indication indicative thereof includes a rotatably mounted indicator flag. The flag is positioned in either a reset indicating or a fault indicating state by a four-pole magnetic pole piece, which is magnetized to an appropriate magnetic orientation by momentary application of a current to an actuator winding on the pole piece. A first magnetically actuated reed switch in an auxiliary magnetic circuit associated with a first pole of the magnetic pole piece and including the actuator winding and a first bias magnet closes upon occurrence of the fault current to connect an internal lithium battery to an LED visible from the exterior of the fault indicator housing. A second magnetically actuated reed switch associated with a second pole of the magnetic pole piece and including the actuator winding and a second bias magnet closes upon occurrence of the fault current for external signaling or control purposes.

High sensitivity magnetic circuit

Abstract: For increased sensitivity a position sensor includes a magnetic circuit in which the stationary portion includes a permanent magnet whose width is optimally 1.5 times the tooth pitch of the exciter portion of the sensor and the magnet face proximate the exciter includes a thin layer of ferromagnetic material over which is centered a narrow magnetic sensing element, such as a magnetoresistor. The sensing element has a width typically less than the tooth width which is between 0.17 and 0.37 the tooth pitch. The needed flux density is typically available simply by appropriate magnet thickness or choice of magnet material without the need of a flux guide.