| 摘要 |
PURPOSE:To compose a three-wiring type differential transformer of two windings and to prevent the occurrence of an error originating from ambinet temperature and connecting cord length, by performing the quotient arithmetic of the difference and the sum between terminal voltage of two secondary windings through the middle point. CONSTITUTION:A differential transformer converter 1 buried under the ground and used for a long period consists of a primary coil 6, a movable magnetic core 5, secondary windings 2 forming two coils 2a and 2b across the middle point, etc. The terminal voltages and B of those coils 2a and 2b increase and decrease reversely according to the movement of the cil 6 and their sum voltage A+B is unchanged, so that even if a current varies owing to fluctuations of temperature, etc., the voltges A and B are in proportion to a current flowing through the winding 6. Further, the load impedance ratio of connecting cords of the coils 2a and 2b symmertical to the middle point is constant without reference to their cord lengths. Therefore, the three-winding type differential transformer is composed of two windings and the occurrence of an error in measured value which is obtained by the quotient arithmetic of a difference voltage A-B and sum voltage A+B by an arithmetic device and corresponds to the movement of the magnetic core 5 due to fluctuations of ambient temperature and connecting cord lengths is prevented. |
