Bearing Metal Temperatures

Type of bearing?

For white metal - upto 80-90⁰C OK (Limit) - but should check the bearing manufacturer recommendation

Antifriction (roller) - 100-110⁰C (in certain modern bearings upto 125⁰C)

Temperature difference exist between machines and is no cause of alarm, The alarm should be on when there is a time rise of temperature and other signals (vibration, debris in return lube oil, ...)

Type of bearing: plain journal bearing (whie metal) combine with trust bearing.

Type of lubrication: Oil ring lubrication

Speed: 600 rpm

when Full speed no load bearing temperatur 45 deg. C

But at base load 800 kw bearing temperatur reach 59 deg. C

other tyical unit bearing temperatur only 45 deg.C

My boss complain me... why was bearing temperatur higher than other?

is there any standard for low speed journal bearing (Micro hydro power) temperature limit related with shaft speed?

Your suggest will useful to ensure my boss that 59 deg.C is allow able or not allowable..

Thank you....

Dear Guesst,

The range indicated for white metal of 80 to 90 Deg.C is very high. It should be up to 84 deg.C for safe operation. Around 86-87 it starts loosening and prove to be severe problem. Further it depends up on clearance and heat-removal rate also.

DHAYANANDHAN.S,

INDIA.

Look at the links given in #5.

or

https://www.machinerylubrication.com/article_detail.asp?articleid=906

Of course it depends on the type of the white metal used.

As OEM, normally we like to keep lots of factor of safety in our hands so that even if the customer (user) misbehaves, our product doesn't. And also we have to ensure that the local temperature (except in case of thinly shelled bearings, the pick-up point may be a bit far away from the hot spot(s)) do not overshoot the limits.

59 deg C is not a problem in itself. The fact that it is so much higher than an identical unit is your bosses concern. There are so many possible reasons for this.

First - check the depth of the oil ring in the oil. Too shallow =not enough oil. Too deep = slipping - not enough oil.

Remember most of your oil is used for cooling so also check the oil cooler or fins or whatever maintains the oil temperature for any differences.

Again, 59 deg C in itself is not a problem

As mentioned in earlier post 59⁰C by itself is no cause for alarm, unless it has a trend. What is your lube oil temperature for this and other set ?

Each machine has its own parameter and as far as they are maintained, no alarm must be raised.

Also check the lube oil flow as the post #3 mentioned and by any chance there is any choking or other problem, just to ensure. But things, if steady are normal.

Look at page 48 the bearing temperatures are explained and you can see you are nowhere near the limits.

Maximum operating temperature for Babbitt is 300º F. In motors 180º F to 190º F is considered running hot. Some turbine applications run as high as 225° F. Many technicians however, will set the alarm at 185º F and trip at 205º F.

here look the table in the end.

Here some explanation and oil selection.

I think these will be enough to convince your boss. But the fact is still, it is normal in absence of trend. This type of temperature and the differences are regular feature of machines. Of course the difference is a bit high, 15⁰C for us it will be about 5⁰C. But then we are OEM with everything brand new, for you it is 1922 machine. Differences do crop up after a century