Patent GB-585002-A (GB)
Title: Improvements relating to feeder systems interconnecting a power generator and a load
IPC: H03H7/40
Filed: 1944-12-01
Abstract: 585,002. Aerial feeding arrangements ; impedance networks. FERRANTI, Ltd., TAYLOR, M. K., and GREENHALGH, J. Dec. 1, 1944, No. 23997. [Classes 40 (iii) and 40 (v)] [Also in Groups XXXV and XXXVI] In a feeder system connecting a power generator to a load, the potential differences set up between two pairs -of points by standing waves, caused by mis-matching between the feeder and the load, are used to drive means for automatically correcting the matching between the feeder and the load. A normal oscillator G is coupled by transformer 2 to the feeder, which is joined to the secondary 3 of the transformer by a series condenser 5. The feeder consists of three # networks, P<1>, p<11>, P<111>, which comprise series inductances 6, 7, 8, connected to earth by shunt condensers 10, 11, 12, 13. The network P<1111>, connecting the feeder to the load 4, comprises-a a series inductance 9, shunted by variable condensers 14, 15. The ends w, x, y, z of inductances 6, 7 and 8 are connected to the anodes of diodes 16w ... 16z respectively, the cathodes of which are connected to the control grids of amplifier valves 22w ... 22z respectively. The anodes of valves 22w and 22y are connected through the halves 24w, 24y of the field winding of a motor M<1> to the H.T. supply, by way of switch S<1>. Similarly, the anodes of valves 22x, 22z are connected through the halves 24x, 24z of the field winding of another motor M<11> by switch S<11>, to the H.T. supply. Transformer 2 is designed to match the oscillator G to the feeder, while the network P<1111> can be made to match the load 4 to the feeder by variable condensers 14, 15, which are driven by motors M<1>, M<11>. If the load is correctly matched to the feeder, there will be a uniform potential distribution along the feeder. If, however, the load is mismatched, standing waves will be set up in the feeder, and a potential difference will exist between wand y if the mis-matching is due to the introduction of a reactive component of the load, or between x and z if the mis-matching is due to a change in the magnitude of the load. On closing switch S<1>, motor M<1> will rotate if points w, y are at different potentials, driving condenser 14, thus compensating for the change of the reactive component of the load. Switch S<1> is now opened and switch S<11> closed, when motor M<11> will rotate if a potential difference exists between points x, z, driving condenser 15, thus compensating for a change in the magnitude of the load. Adjustment of either condenser will cause a change in potentials at the four points w, x, y, z, and therefore switches S<1>, S<11> are alternately opened and closed till a balance is obtained. In a modification, the switches S<1>, S<11> may be alternately opened and closed automatically. The arrangement can also be used for measuring the magnitude and phase angle of impedances. The unknown impedance forms the load 4, and condensers 14, 15 are calibrated so that when correct matching has been obtained, the characteristic of the impedance can be obtained from previously-drawn curves.