Publications Details
SERAPHIM: A magnetic propulsion scheme for fast trains
We are attempting to develop and demonstrate a new type of linear synchronous induction motor capable of propelling a vehicle at high speed. The technology, based on a passive guideway containing sequential aluminum plates, was developed in Sandia`s electromagnetic launch program. As such, it was called a ``re-connection gun`` and launched an aluminum plate from between pairs of pancake coils. In the proposed propulsion scheme, the plates are fixed and the coils move. Pairs of closely spaced pancake coils on the vehicle straddle vertically mounted aluminum plates in the roadbed. The current in the coils is turned on when the plate is fully covered, peaks at some optimal time, and decreases to zero before separation. This induces currents in the plate which interact with the coil current to produce repulsive forces. In essence, the pulsed coils push off the edge of the plate because at the high frequency of operation, the current has insufficient time to fully penetrate. Since no embedded flux is required, the efficiency actually increases with speed. This concept has been named SERAPHIM, for SEgmented RAil PHased Induction Motor.