Patent GB-657035-A (GB)
Title: High frequency electric transport system with contactless transmission of energy
IPC: B60L5/00
Filed: 1946-03-26
Abstract: 657,035. Electric traction. BABAT, G. I. March 26, 1946, No. 9269. [Class 104 (iii)] Vehicles receive highfrequency current inductively through two coupled oscillatory circuits, one comprising a conducting network laid along the roads and the other a receiving frame on the vehicle. The network is divided into isolated sections, each with its own power sub-station, and may be laid along the road bed or carried by overhead wires. The vehicles may carry auxiliary batteries so as to be able to travel some distance from the network, the vehicles carrying rectifiers so that the batteries may be charged direct from the induced current or regeneratively. Regulation of the power absorbed by the vehicles is effected by varying the tuning of the frame circuit, or by varying the shape or size of the frame. Fig. 1 shows the supply system consisting of sub-stations 1-4 receiving high voltage direct current from the central rectifier 5. Alternatively, each sub-station may have its rectifier supplied direct from the .three-phase mains. The networks may be switched in automatically on the approach of a receiving frame. Fig. 2 shows the circuits for one track section and one vehicle. The sub-station consists of the rectifier A, the valve generator B and the approach control C, whilst D is the conducting network and F the vehicle circuit. Current from the mains 201 passes to a transformer 202 feeding rectifying valves 203 giving the supply to a choke coil 204 leading to a generator valve 205 with a grid-leak condenser 207 and a grid choke 208. The tank circuit comprising anode coil 209 and condenser 210 connected through condenser 206 to the supply from the rectifiers 203 delivers high frequency current to the track network which is also provided with compensating condensers 211 . . . 213. The approach control C consists of a coil 224 receiving current from rectifiers 203 and holding the contacts 225 of the grid control circuit whilst energy is being taken from that section of the network. When this ceases, contacts 225 open and a condenser 226 is connected through the resistance 230 to the grid of valve 205 applying a large negative potential and quenching the oscillations. The approach control also includes low-power valve generator 214 and an ammeter 215 controlled by a contact 216 of a relay 217. The vehicle circuit F includes the receiving frame 231, condensers 232, 233, 235, 237 and rectifiers 234, 236. The storage battery 243 has a control switch 244 and the traction motor has an armature 239 with reversing switch 240 and series and shunt windings 241, 242 with switch 245. The resistance and reactance values of the network are made greater than those of the receiving circuit on the vehicle. Fig. 14 shows a highway with a network laid along the road bed. The foundation is lined with a trough of thin copper or a series of copper strips 145 forming an outer screen. The active conductor consists of an oval tube 143 arranged on a core and provided with very thin walls. Unequal distribution of current and potential may be compensated and nodal points eliminated by condensers and inductances inserted into the line, one of the wires of which is divided into short isolated sections. Large areas may be supplied uniformly by employing mutually perpendicular progressive fields. Fig. 23 shows a network consisting of three sections A, B, C supplied with high-frequency currents having a relative phase shift of 120 degrees to set up a progressive field, the conductors being divided into separate oscillators. Specifications 9983/92, [Class 104], 615,916, [Group XXXV], and 657,036 are referred to.