Fan bearing temperature
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Dear experts, I have an ID fan here with a main air handling capacity of 75,000 m3/h and an air pressure of 9,000 Pa. The motor driving the fan is 250 KW in capacity. It has been in operation for 3 years now, during which only the carbon ring seal has been replaced. In the past 3 days, there have been sequential temperature trips; the set temperature for such trips was 70°C, while the highest operating temperature reached 73°C. The vibration value of the bearing housing is <1, and the current is around 200A. Actual on-site temperature measurements showed around 50°C on the impeller side outside the bearing housing, and around 70°C on the motor side. The bearing cover has been opened; the lubricating grease and retaining rings are all in order. Are there any other possible causes? I would be very grateful if you experts could give me some advice.
It has been running for too long; it should be disassembled for a thorough overhaul and maintenance. The inspection items include the clearance of each bearing, the levelness of the unit rotor, the tightness of the base bolts, the removal of scale from the rotor, determination of whether dynamic balancing is necessary, cleaning of the motor, replacement of oil, cleaning of the oil tank, and inspection of the coolers. If this continues, it might be ruined any day; for your reference.
The fan brand is foreign, and its tolerance fit and quality are generally recognized as good. Current concerns: There is slight wear on the bearing balls (the bearings have been in use for 3 years without being replaced), but the wear is minimal and does not affect vibration measurement (actual vibration levels on site are <1 mm/s); however, it may impact instantaneous temperature measurement. Do you think it’s correct?
Yes, we are indeed planning to address this during the next major maintenance shutdown. We have already increased the interlock temperature from 70°C to 80°C, but we still want to investigate the cause.
This approach of improving the chain is nothing but covering one’s ears while stealing; if you are not the decision-maker, you should not approve of such a method. Given the current situation, there is a high possibility of a short-term deterioration. Don’t think that a bearing won’t get damaged just because its temperature is not high. In the case of sliding bearings lubricated with thin oil, the lubricating oil helps to keep the bearings operating at a constant temperature. Once the wear becomes excessive, rotation will be impaired as a result of the damage. If you’re the one manipulating, then get ready to take the fallout – for your information.
Trying to cover up the problem in this way can easily cause damage to other components of the equipment; the original poster might want to try contacting the manufacturer to resolve the issue!
Take a look at the vibration spectrum to see if the bearing raceways are severely worn
This bearing is 2220K C3 and is lubricated with grease. It is precisely to avoid drastic changes that we continue to explore the reasons. No one wants to stop the vehicle for no reason and incur operational losses.
The spectrum has been checked; there are no issues. I contacted the manufacturer, and they agreed with my view. What’s the explanation?
There’s a spectrum being emitted; those who are experts in vibration can take a look at it