In hydrodynamic journal bearings, the shaft and the bearing shell are separated from each other by a lubricating film during operation. The supporting function of the lubricating film in a journal bearing can be described by the pressure distribution in the bearing gap.
The TM 280 unit is used to visualise the pressure curve in the journal bearing with hydrodynamic lubrication. To do this, there are twelve measuring points around the circumference of the bearing shell and four measuring points in the longitudinal direction. The respective pressures can be read via a 16 tube manometers with reference to the height of the liquid columns.

The journal bearing comprises an electrically driven shaft journal that rotates in a freely movable bearing housing. Oil is used as the lubricant.
The displacement of the shaft journal depends on the speed and direction of rotation as well as the characteristic behaviour during start-up, and can be observed through the transparent bearing housing. Speed and direction can be adjusted. The load on the journal bearing can be adjusted by varying the weights. The temperature in the bearing gap is measured in order to determine the viscosity of the lubricant.