| 摘要 |
PURPOSE:To contrive miniaturization and high precision of a sensor connected to a ship speedometer by connecting electrodes to an oscillation plate provided on the edge of a core of an electromagnet. CONSTITUTION:In cases where a ship speed is measured with magnetism, switches SW2, SW3 are changed over to the side of (a) the other side of (b) respectively, an electromagnet 1 is excited with an excitation signal transmitted from an excitation circuit 9, the excitation signal is received with a signal receiving part 13 as a speed signal in which inductive electric power generated on electrodes 3 is in proportion to the ship speed by means of magnetohydrodynamic action caused by a generation magnetic field, processed with a control part 12 and displayed on a display part 14 as the ship speed. Next, when the ship speed is measured by means of ultrasonic waves, the switches SW, SW3 are changed over to the side of (b) and the other side of (d) respectively, a switch SW1 is turned to the side of (e) during excitation current production due to a changing-over signal transmitted from a clock circuit 11, the electromagnet 1 is excited through the side of (d), when excitation current is stopped, the switch SW1 is changed over to the side of (f). and the electromagnet 1 is connected to the receiving part 13 because the ultrasonic wave produced by means of excitation is received by next timing. Thereby an electromagnetic method can be constituted integral with an acoustic method. |
