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A method and apparatus for high speed magnetic detection of surface fatigue cracks in railway rails. The magnetic material of the rail is magnetized by touch magnetization using a permanent magnet (31), leaving a remanent magnetic field. A sensor head (30, 50) having a plurality of Hall effect senso

A method and apparatus for high speed magnetic detection of surface fatigue cracks in railway rails. The magnetic material of the rail is magnetized by touch magnetization using a permanent magnet (31), leaving a remanent magnetic field. A sensor head (30, 50) having a plurality of Hall effect sensors (32) senses stray flux generated in the vicinity of surface fatigue in the rail head by the remanent magnetic field. The sensor head (30, 50) may incorporate a proximity sensor (60) to compensate for variations in sensor height. The apparatus may be mounted on a conventional track recording vehicle (TRV) for use in routinely monitoring the surface fatigue severities in rail along a railway.

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A method and apparatus for high speed magnetic detection of surface fatigue cracks in railway rails. The magnetic material of the rail is magnetized by touch magnetization using a permanent magnet (31), leaving a remanent magnetic field. A sensor head (30, 50) having a plurality of Hall effect senso

A method and apparatus for high speed magnetic detection of surface fatigue cracks in railway rails. The magnetic material of the rail is magnetized by touch magnetization using a permanent magnet (31), leaving a remanent magnetic field. A sensor head (30, 50) having a plurality of Hall effect sensors (32) senses stray flux generated in the vicinity of surface fatigue in the rail head by the remanent magnetic field. The sensor head (30, 50) may incorporate a proximity sensor (60) to compensate for variations in sensor height. The apparatus may be mounted on a conventional track recording vehicle (TRV) for use in routinely monitoring the surface fatigue severities in rail along a railway. three-phase power supply, said inductive charger provides a power factor of approximately 0.91. 8. The inductive charger of claim 1 wherein said rectifier includes first, second and third legs, and wherein each of said first, second and third legs include first and second diodes. 9. The inductive charger of claim 1 wherein said rectifier includes first, second and third legs, and wherein both said first and second legs include first and second diodes and said third leg includes first and second controlled switches. 10. The inductive charger of claim 9 wherein said controlled switches are silicon-controlled rectifiers. 11. The inductive charger of claim 1 wherein said controller includes: an amplifier that generates a current reference signal from said input current; an attenuator that produces a voltage reference signal from said input voltage; a multiplier that generates a product signal based on said voltage reference signal and a power command signal; a differential circuit that generates an error signal and that has an inverting input connected to said current reference signal and a non-inverting input connected to said product signal; a compensator that generates a compensated signal from said error signal; and a gate driver that produces drive signals for said switching circuits of said inverter. 12. The inductive charger of claim 11 wherein said attenuator rectifies and attenuates said AC line voltage. 13. The inductive charger of claim 1 wherein said inductive charger has a first output power when connected to said single-phase power source and approximately twice said first output power when connected to said three-phase power source. 14. An inductive charger system comprising: a rectifier that can be connected to both single-phase and three-phase power sources and wherein said rectifier includes first, second and third legs; a filter capacitor coupled across said rectifier; an inverter coupled to said rectifier and said filter capacitor; a series resonant tank circuit coupled to said inverter; a charge coupler and inductive inlet including a transformer and a parallel resonant tank circuit for coupling energy to a load; and a controller for regulating power supplied to said load by increasing said operating frequency of said system to reduce output current for a given voltage. 15. The inductive charger of claim 14 wherein said inductive charger system has a first output power when connected to said single-phase power source and approximately twice said first output power when connected to said three-phase power source. 16. The system recited in claim 14 wherein said filter capacitor comprises a high frequency non-electrolytic filter capacitor. 17. The system recited in claim 14 wherein said inverter includes a MOSFET-based full-bridge inverter. 18. The system recited in claim 14 wherein said inverter comprises a MOSFET-based half-bridge inverter. 19. The system recited in claim 14 wherein said load includes batteries of an electric vehicle. 20. The system recited in claim 14 wherein said full bridge inverter includes a plurality of controlled switches, intrinsic anti-parallel diodes, and snubber capacitors to facilitate zero-voltage-switching. 21. The system recited in claim 20 wherein first and third switches of said inverter are gated to second and fourth switches of said inverter in a complementary fashion.