I want to install a PT100 into a bearing antifrition 1

[181273]

hello everybody, I`m electric guy, learning something on bearings, I´d to install a PT100 into a old bearing, I wanna know what`s the distance from the antifriction layer to put the head of my PT100, and what could be the real temperature diference between my reading and the real one.
thanks in advance for everybody

 

[stgrme]

RTDs (PT-100) and thermocouples are installed in sleeve type journal bearings all the time. The distance from the antifriction (babbitt) surface depends on the diameter of the hole for the PT-100. If the distance is too small the babbitt will "dimple" (form a depression) or fail. Typical minimum babbitt thicknesses for different hole diameters are as follows:
Hole Diam: 0.250 inch Min. Thickness: 0.080 inch
Hole Diam: 0.375 inch Min. Thickness: 0.130 inch
Hole Diam: 0.500 inch Min. Thickness: 0.180 inch

I can't tell you what the difference from the actual difference will be, but as I mentioned above, this type of installation is very common. I actually prefer "tip-sensitive" thermocouples for faster response.

The following tips will improve the quality of the installation and measurement:

1. Use a "flat bottom" (rather than "pointed") drill bit to make the hole.

2. Make sure the tip of the RTD or thermocouple is in contact with the babbitt. (Spring-loading works best).

3. Purchase a "tip-sensitive" RTD or thermocouple.

4. Be careful about grounding (earthing). If the tip is grounded do not ground the sheath at the opposite end.

MINCO has an on line catalog and other technical information on their website:

http://www.minco.com

Good luck with your installation!