Document om6Yp8amoKLva9EOexJ36dE53

MARATHON OIL ROBINSON, ILLINOIS S.O. 7339 Background The subject unit is an SQV7-6, S.O. 7339R1, and drives two Dresser Rand (Clark Brothers) compressors. The drive-through compressor is a 3M 3-stage compressor S/N 3-3-248. The outboard compressor is a 2M 6-stage unit S/N 2-6-249. The string was rerated and converted to an electronic governor in the Spring of 1988. The unit had run well until late June when a thrust bearing failure occurred. The governor control had been deteriorating prior to the failure. During the outage work was done to the valve rack, servo motor, and the governor (see A. Hurt's report dated 6/30/91). These charges had resulted in stable operation at all but one point. At 81 percent valve opening the speed would start varying approximately 100 rpm. Marathon requested a Service Engineer to trouble shoot the problem and advise what changes could be made to improve the system. Site Visit After arrival at site and meeting with Messrs. Stone and Jungen, proceeded up to the unit. Three dial indicators were obtained and mounted to monitor various parts of the servo motor linkage. The locations are as indicated below: