The Kingsbury Thrust Bearing

Hydropower plants pioneered big generators. The first plants used units with horizontal shafts. Here are some examples.

1907 MWRD Lockport via Dennis DeBruler

1907 Croton via Dennis DeBruler

 

1909 Dam #4 via Dennis DeBruler

1911 or earlier via Dennis DeBruler

1911 Marseilles via Dennis DeBruler

1913 Healey Falls via Dennis DeBruler

In 1896, Professor Kingsbury invented a thrust bearing that required just one thrust collar on the shaft. [26:57 video @ 7:29] He was researching oil lubrication, and he figured out how to use oil under high pressure to support high forces between the single shaft collar and the bearing. This allowed a bearing at the bottom of a vertical shaft to support the tremendous weight of a generator and its turbine. While watching the video, I realized that the waterwheels in the Lockport and Croton powerhouses had balanced axial forces. Specifically, the water comes out of both sides of each waterwheel. 

The ASME has some different dates: "His first experimental bearing was tested in 1904. He filed for a patent in 1907, and it was granted in 1910." The first Kingsbury bearing in hydroelectric service was installed in the Holtwood Hydro Plant in 1912.

1912 Holtwood via Dennis DeBruler

The 1913 Keokuk Powerhouse used roller bearings in half the units and Kingsbury Thrust Bearings in the other half. The bearings were four times larger than the prior art, so they were effectively experimenting with thrust bearings. 

1913 Keokuk via Dennis DeBruler

This is the post that motivated me to research thrust bearings.

Pacific Northwest Hydroelectric Power Plant Operators posted @ 0:03
For everyone out there like me that wondered when the Thrust Bearing Oil Pump (High Lift Pump) pressure relief valve would ever operate, the answer is every single time the pump initially starts. Pretty cool to be able to witness this with the thrust bearing tub completely removed.
[Note the "fountain" of oil near the middle of the screenshot.
We can see that each shoe has a pipe that feeds it oil.]

Shove the slider to about 0:12 seconds and listen to the shoes drop.

Pacific Northwest Hydroelectric Power Plant Operators posted
Once in a lifetime opportunity to see the thrust bearing shoe stripper bolts doing their job during a unit brake jacking evolution.
Neil Jacobson: Amazing how much suction power there is between two metals with a fluid between them.

Another video with the comment: "Thrust Bearing Shoe Stripping."

Neil Jacobson: If I remember right there is a permissive limit switch that has to be closed to allow start up.

Andy Michel: Neil Jacobson Yes, based on pressure.

The above referenced video (26:57) made me realize that just because a shaft is horizontal does not mean there are no axial forces. That was when I checked the diagrams of Lockport and Croton and realized that the water wheels have just radial forces because the axial forces are balanced. But steam driven turbines would have a massive amount of axial force because of the steam pushing against all of those blades. That is why this turbine has five thrust collars. It is from the early 1900s and high-performance, single-collar thrust bearings have yet to be invented.

Dennis DeBruler