Seek advice on abnormal fluctuations in the bearing temperature of the main fan unit gearbox
Thread Content
After each shutdown, the bearing temperature of the high-speed shaft support bearing in the gearbox of our main fan unit rises gradually; for example, from March to August 2020, it increased from 83°C to 92°C. Recently, peak fluctuations have occurred frequently: temperatures start to rise rapidly from around 93–95°C, following an exponential growth pattern with an increasing rate of increase, until they reach a peak in the range of 95–105°C; after that, the temperature drops quickly, with the decline following a nearly vertical curve. By observing the curve, it can be seen that each such peak occurrence takes place during periods when the temperature of the lubricating oil drops rapidly; as the temperature of the lubricating oil decreases, the temperature of the bearing at that location also decreases, and this cycle repeats itself over several days. Could the experts please help analyze what exactly the cause is?
This is related to the fuel supply method. There are lubrication methods such as light oil lubrication, light oil circulation cooling, and glycerin lubrication. I’m not sure which category your device falls into; please let me know. Or things related to operation.
It’s impossible for the temperature to drop in a straight line after it rises. The temperature drop should be a gradual process. You can check the gauge temperature probe. The slow increase in shutdown temperature may be due to poor oil return or positive pressure in the oil tank; this should be checked. It’s not clear whether the situation described later refers to a shutdown or an operational state, so it’s impossible to determine. The gearbox uses thin-walled bearings and is very sensitive to temperature rise.