Reduced voltage braking system in a linear motor in-track transit system

Abstract

A transit system implementing a reduced voltage braking scheme is provided. The transit system includes a guideway extending between freight loading and freight unloading stations. Freight carrying vehicles are moveable along the guideway between the stations. The guideway is divided into a number of blocks with each block including at least two linear motor primaries located along the guideway at spaced intervals. A controller is associated with each block and communicates with the linear motor primaries as well as with sensors positioned along the guideway within the block. The controller is in communication with the controllers in the adjacent upstream and downstream blocks and provides an occupied signal to the upstream block when a vehicle is detected in the block. When the controller receives an occupied signal from the downstream controller, the controller conditions the linear motor primaries in the block so that when a vehicle enters the block, it is stopped by the linear motor primaries within the block. To reduce large currents from being drawn by the linear motor primaries during the braking operation, the voltage of the power supply is stepped down by a transformer before it is supplied to the linear motor primaries. Since a plurality of linear motor primaries are provided in each block, the applied voltage can be reduced while still providing sufficient braking thrust in the block to stop a vehicle if required.