| 摘要 |
<p>400,918. Thermionic valve circuits. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Palmer, H. L. ; 245¢, Mohawk Avenue, Scotia, New York, U.S.A.) Jan. 29, 1932, No. 2748. Convention date, Jan. 29, 1931. [Class 40 (v).] In a Wheatstone bridge arrangement fo controlling the operation of thermionic valves the filament of the valve (or valves) is included in the bridge circuit and constitutes one (or both) of the thermally responsive resistances therein. A Wheatstone connection 5, 11 and 4, 10 is made to one phase of a three phase supply 12, the impedances 10, 11 being transformers which supply the filaments 8, 9 of two three electrode valves, these filaments being of tungsten and having a high positive temperature coefficient of resistance. The grids 21, 22 of the valves are connected through resistors 23, 24 the secondary of a transformer 13 and bias battery 25 to the mid point of the filament heating and anode supply transformer secondaries 10, 11, 14 and the primary of the transformer 13 is connected to the output terminals of the bridge. The anodes of the valves are connected to opposite ends of the transformer 14 and include winding 17, 18 in their respective circuits which windings when energized actuate switches 19 or 20 to reverse the connections of one phase to a 3-phase reversible motor 3 to reverse its rotation.</p> |
