Since the subject of this article is somewhat not-that-easy to understand, I suggest starting with the basics of the synchronous motor. In the synchronous motor, the basic magnetic field is obtained by direct current excitation rather than through the air... Read more

The post The art of achieving synchronous motor transient stability (especially in weak grids) appeared first on EEP - Electrical Engineering Portal.

A device and method to determine the stopping rotor position of a washing machine motor includes an inverter, a permanent magnet synchronous motor, and an electronic motor controller. The controller determines the stopped rotor position of the motor by measuring induced currents in the stator field coils of the motor. While the motor is de-energized and slowly rotating, the controller directs the inverter to connect all of the stator field coils of the motor together. The stator field coils may be connected to a common D.C. rail, output from an A.C.-D.C. converter of the washing machine. In an embodiment, the controller determines the rotor position based on the polarities of current induced in the stator field coils. In another embodiment, the controller determines the rotor position based on the phase angle and angular frequency of the three phase currents, transformed into a stationary reference frame.

Aspects of the invention provide a transport system powered by short block Linear Synchronous Motors (LSMs). The use of short blocks allows vehicles to move under precise control even when they are in close proximity to each other. The design allows the vehicles to be propelled and guided while negotiating sharp turns and negotiating merge and diverge switches. A coreless LSM can be used to create propulsive force without attractive force so as to allow a relatively high drag vehicle suspension, such as a vehicle sliding on a smooth surface. Further aspects of the invention provide a switching member that is selectively moveable relative to a guideway in order to change a magnetic force acting on the vehicle transverse to a direction of motion of the vehicle.

The invention provides in some aspects a transport system comprising a guideway with a plurality of propulsion coils disposed along a region in which one or more vehicles are to be propelled. One or more vehicles are disposed on the guideway, each including a magnetic flux source. The guideway has one or more running surfaces that support the vehicles and along which they roll or slide. Each vehicle can have a septum portion of narrowed cross-section that is coupled to one or more body portions of the vehicle. The guideway includes a diverge region that has a flipper and an extension of the running surface at a vertex of the diverge. The flipper initiates switching of vehicle direction at a diverge by exerting a laterally directed force thereon.

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