Hydrostatic Asymmetric Journal Gas Barings for Seismic ACROSS Transmitters

Abstract

The ACROSS (Accurately Controlled Routinely Operated Signal System) is used to detect subtle changes in the physical state of Earth's structure. The signal is sinusoidal elastic waves generated by the rotation of a rotor with eccentric mass set in ACROSS transmitters. In currently working transmitters, since the rotor is supported by rolling contact bearings, bearing losses are so large that the cooling, lubrication management and bearing life become serious problems. To solve these problems, hydrostatic asymmetric journal gas bearings have been proposed to support the eccentric mass rotors. This paper describes the experimental investigation of rotational characteristics of proposed hydrostatic asymmetric journal gas bearings. It is verified that the rotor amplitude in the journal bearings can be zero at a certain rotational frequency by using trial test rig. In order to decrease the gas consumption and increase more safely operation, test of rotational frequency modulation using electro-pneumatic pressure regulator was carried out. In fixed supply pressure condition, rotor amplitude largely changes in accordance with change of rotational frequency. In controlled supply pressure condition, the rotor amplitude decrease under the operation and the gas consumption also largely decreased.

Keywords

• hydrostatic gas bearing
• asymmetric bearing
• rotor amplitude
• gas consumption
• large eccentricity
• frequency modulation
• seismic source