In rare cases rolling bearings fail by WEC (white etching crack) damage before reaching their calculated rating life, if so called additional loads are applied on the bearing in addition to the normal Hertzian stre...In rare cases rolling bearings fail by WEC (white etching crack) damage before reaching their calculated rating life, if so called additional loads are applied on the bearing in addition to the normal Hertzian stress (PHz). A number of additional loads have been identified by means of tests with rolling bearings. These can be small direct currents as a result of electrostatic charge or large alternating currents from inverter-fed drives that unintentionally flow through the bearing. WEC damages can also be initiated by a pure mechanical additional load which is dependent on factors including the bearing kinematics but also on the dynamics of the drive train. The current state of knowledge on this subject is presented and taken as the basis for developing a hypothesis on the WEC damage mechanism. If load situations critical for WEC cannot be avoided, the risk of WEC can be considerably reduced by the selection of suitable materials and coatings as well as, in some cases, of suitable lubricants.展开更多
In order to study the relationship between the triggering current, deuterium pressure and the excess heat, a series of experiments were made in a D/Pd gas-loading system. By comparing the system constants (k = AT//kP...In order to study the relationship between the triggering current, deuterium pressure and the excess heat, a series of experiments were made in a D/Pd gas-loading system. By comparing the system constants (k = AT//kP) in both nitrogen and deuterium atmosphere we found an optimum current (8 A) and a deuterium pressure (9 x 104 Pa) in which the system could release a maximum excess power (more than 80 W). The reproducibility was 16/16 and the excess energy released in the longest experiment was about 300 MJ within 40 days, which was corresponding to 104 eV for each palladium atom. Analysis of the palladium surface with a SEM (scanning electron microscopy) and an EDS (energy dispersive spectrometer) revealed that some new surface topographical feature with concentrations of unexpected elements (such as Ag, Sn, Pb and Ca) appeared after the current triggering. The results implied that the excess heat might come from a nuclear transmutation.展开更多
文摘In rare cases rolling bearings fail by WEC (white etching crack) damage before reaching their calculated rating life, if so called additional loads are applied on the bearing in addition to the normal Hertzian stress (PHz). A number of additional loads have been identified by means of tests with rolling bearings. These can be small direct currents as a result of electrostatic charge or large alternating currents from inverter-fed drives that unintentionally flow through the bearing. WEC damages can also be initiated by a pure mechanical additional load which is dependent on factors including the bearing kinematics but also on the dynamics of the drive train. The current state of knowledge on this subject is presented and taken as the basis for developing a hypothesis on the WEC damage mechanism. If load situations critical for WEC cannot be avoided, the risk of WEC can be considerably reduced by the selection of suitable materials and coatings as well as, in some cases, of suitable lubricants.
文摘In order to study the relationship between the triggering current, deuterium pressure and the excess heat, a series of experiments were made in a D/Pd gas-loading system. By comparing the system constants (k = AT//kP) in both nitrogen and deuterium atmosphere we found an optimum current (8 A) and a deuterium pressure (9 x 104 Pa) in which the system could release a maximum excess power (more than 80 W). The reproducibility was 16/16 and the excess energy released in the longest experiment was about 300 MJ within 40 days, which was corresponding to 104 eV for each palladium atom. Analysis of the palladium surface with a SEM (scanning electron microscopy) and an EDS (energy dispersive spectrometer) revealed that some new surface topographical feature with concentrations of unexpected elements (such as Ag, Sn, Pb and Ca) appeared after the current triggering. The results implied that the excess heat might come from a nuclear transmutation.