The conditions of lubricant are vit

The conditions of lubricant are vital for industrial machine efficiency as they are related to machine damage caused by lubricant deterioration. From previous studies [1,2], it can be noted that machine failures would be influenced by the lubricant with low quality. Theoretically, the lubricant for each type of machine should be used in specific period. However, the lubricant conditions would be gradually deteriorated earlier than expected due to metal particles cased by machine wear itself or exterior contamination and also the maintenance period would not be appropriate for a given machine. From [3,4], it was observed that more than 50% of lubricant replacement would be performed even though the lubricant is still in good condition and usable that leads to excessive cost. At present, there are several studies proposing the experiments on lubricant conditions by using several methods such as Ultrasonic measurement of viscosity of liquids, Photoacoustic measurement of liquid viscosity, Measurement of magnetic viscosity in NdFeB, A viscosity and density meter with a magnetically suspended rotor, Capacitive sensor, IR-absorption and optical fiber sensing [5-11]. This study is an alternative measurement by using magnetic field together with Hall Effect sensor