Proper bearing temperature measurement

[233055]

I'm looking for information to help me in knowing exactly where to measure the temperature of a bearings in a marine gearbox, i.e, where should the probe be. I assumed that the same location on all would be appropriate, but I get different temperatures on 2 differents vessels with identical gearboxes.

 

[diamondjim]

Sounds like you are on track. The nearer to the
raceway would be best. It is not surprising that
they differ, but by how much? Tolerances, machining
accuracies, alignment, loads, etc. would be unique to
each vessel. If they were very discrepant in values,
I would start to worry about the higher value and
monitor that bearing very closely.

 

[233055]

Many thanks diamondjim for taking time to respond. I thought in the same direction as you at first, but it is not just one bearing that is standing out. I have taken into account almost everything, and thought that if there were a better place to to place a probe I would give it a try.

 

[MASSEY]

An additional factor that affects bearing temperature is the amount and type of grease in the bearings. This is often overlooked and hard to monitor. But it has a large impact in how heat is dissipated through and from bearings.

I have no suggestion how to factor in this varible. Except to start with grease free bearings and add an exact amount of grease to each. I admit this is fuzzy - but the amount of grease in a bearing has a very large impact on heat generation and dissipation.

 

[RHD]

I agree that the best place to measure the brg temp is on the raceway. Since you are finding different temperatures in the same design gearboxes, the loading must be different. How are the brgs mounted? Press fit?

 

[bluemax]

Hello

Measuring bearing temperature is really subjective. If the bearing temp is being measured on the outside housing it is subject to large variations. Have you thought about installing bearing metal thermocouples in the bearing proper during next inspection, thermocouple should be as close to the ID of the bearing as possible without compromising the integrity of the load bearing portion.

 

[AHRBearing]

I believe SKF make many sizes with an integral thermocouple, try your nearest agent for details. This way you may be able to glean exactly where SKF think its best to take readings from.

AHR International Ltd

http://www.ahrinternational.com