Abstract: In a contactless power supply system 10 having a secondary coil 13 receiving electric power generated from a primary coil 12 to be connected to a high-frequency power source 11, and a resonance coil 14 arranged in direct contact with the secondary coil 13 in between the primary coil 12 and the secondary coil 13, respective planarly-viewed areas of the secondary and the resonance coils 13, 14 are equal to or smaller than a planarly-viewed area of the primary coil 12, the primary coil 12 is formed by planarly and spirally winding a first litz wire 25, the resonance coil 14 is formed by tandemly winding coils 27, 28 in a double layer, the coils 27, 28 being formed by planarly and spirally winding a second litz wire 26, and the secondary coil 13 is formed by parallelly arranging and planarly and spirally winding third litz wires 29, 29a.

Abstract: In a contactless power supply system 10 having a secondary coil 13 receiving electric power generated from a primary coil 12 to be connected to a high-frequency power source 11, and a resonance coil 14 arranged in direct contact with the secondary coil 13 in between the primary coil 12 and the secondary coil 13, respective planarly-viewed areas of the secondary and the resonance coils 13, 14 are equal to or smaller than a planarly-viewed area of the primary coil 12, the primary coil 12 is formed by planarly and spirally winding a first litz wire 25, the resonance coil 14 is formed by tandemly winding coils 27, 28 in a double layer, the coils 27, 28 being formed by planarly and spirally winding a second litz wire 26, and the secondary coil 13 is formed by parallelly arranging and planarly and spirally winding third litz wires 29, 29a.

Abstract: The bearing of a machine tool spindle is sealed by a pair of wiping seals mounted on the shaft and resiliently urged into contact with opposite faces of a stationary ring through which the shaft extends. The very small clearance between the ring and the shaft is fed with gas for example air at low pressure. When there is no gas supply and for example when the shaft is stationary the seals contact the ring and the resilience ensures good contact and prevents seepage of for example lubricant along the shaft from one side of the seals to the other. When the shaft is to be driven, low pressure gas is supplied and this pressure deflects the seals to lift them from the face of the ring so that there is no frictional engagement and either power loss or heat generation, and any liquid which does go past the seals is thrown outwardly by centrifugal force and driven by the escaping gas.