| 摘要 |
1506263 Measuring temperatures INTERNATIONAL BUSINESS MACHINES CORP 31 Oct 1975 [13 Nov 1974] 45276/75 Heading G1N The temperature at the bearing 5, Fig. 1, of a crosshead 3 associated with the reciprocating piston 4 of a diesel engine, is measured by a temperaturesensitive resistor RT coupled by capacitors C1-4 and inductor L to external apparatus. Capacitors C3, C4 have one plate mounted on the bearing 5 and the other on the crosshead 3: capacitors Cl, C2 have one plate mounted on the crosshead 3 and the other on the fixed casing 1. Thus all four capacitors are cyclically varied synchronously, and when they are all at maximum capacitance they form a series resonant circuit with inductor L to the voltage of an A.C. generator G, Fig. 3. At resonance the impedance across terminals 6, 7 is minimum and effectively equal to the resistance of the temperature-sensitive resistor R T . The minimum voltage across terminals 6, 7, which occurs at resonance and is proportional to RT, is sensed by a voltmeter 32 and converted at 33 to the temperature value corresponding to this value of RT. |
