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A simple literature review, or search on the Internet for “intermetallic compounds” would lead one to believe that this represents the state of the art in material science.  While the study of many new compounds is on the leading edge of technology, the intermetallic nature of copper and tin in an alloy form has been studied for more than 5000 years.  Without the aid of high tech tools, the Chinese developed the beta bronze alloy form of tin and copper some 1400 years ago.  This was the first metal that could be intentionally heat treated to provide a wide range of mechanical properties.  In more recent research, much attention has been paid to the formation of Cu6Sn5 and Cu3Sn intermetallic compound layers, and their effect on solder joints in electronic assembly.  Unfortunately, little, or no attention has been paid to the identical reaction that occurs when bonding a tin based Babbitt to a copper alloy backing material typical of many fluid film bearings used in industry today.

My first direct exposure to the resultant phenomenon of the formation of these compounds came about 10 years ago.  During the dis-assembly of a high speed gas compressor, the thrust pads were removed from the unit for inspection.  In this particular bearing, the pads were designed with ASTM-B23 Grade 2 babbitt bonded to a copper alloy containing approximately 2% chrome for increased mechanical strength.  In this application, the high sliding velocity present in the oil lubricated thrust bearing would have yielded unacceptably high bearing temperatures if conventional steel backing material had been used.  The copper alloy backing material was used due to its high thermal conductivity to provide improved bearing performance.  In this instance, following successful dimensional checks, and ultrasonic inspection of the babbitt bond, the pads were returned to the compressor deck to be re-installed in the machine.  During the installation process, one of the pads was inadvertently dropped from a height of about three inches on to a steel workbench.  As a result of this minor impact, the babbitt completely separated from the copper alloy backing material.  This was indeed somewhat disturbing that the babbitt could fall off of an otherwise acceptable part that was ready for installation in a very expensive machine that operates in excess of 10,000 RPM.

Careful inspection of the subject thrust pad, the babbitt that had been bonded to the pad, and the remaining 5 pads from this bearing yielded more disturbing questions than answers.  Each of the intact pads could pass an ultrasonic inspection of the babbitt bond, and yet the babbitt could be readily removed from the backing layer with a pocket knife.  Metallurgical inspection of the babbitt and the backing material indicated that all of the material compositions were correct.  Scanning Electron Microscope (SEM) scans of the parts indicated that the failure had occurred along an intermetallic layer that had formed along the babbitt-copper interface.  Literature reviews undertaken at that time, as well as today, would show that the only industry that acknowledges the formation of these intermetallic compounds is the electronics industry.  Apparently, solder joints have been plagued with this problem for generations. 

Babbitt Repair Services

Dove tail grooves in fixed bore bearings



This existing Lube Oil System was provided by a major US supplier and was less than ten years old. It had a number of weak points, the most serious of which was that the DC powered Emergency Lube Oil Pump almost always failed to start pumping oil when it was turned on.


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Dr. Mel's Tech Note is a periodic publication. Over the years, Dr. Mel has accumulated much experience related to power generation and turbo machinery.  These Tech Notes are a sample of some of the problems Dr Mel has solved over the years.

Tech Note June 2019: Hydrogen Seal and Tilt Pad Bearing Upgrades

Tech Note July 2018: Fluid Drive Upgrades; Getting 100,000 hours between overhauls

Tech Note March 2018: Dr. Mel asks, "Why don't you fix it?"

Tech Note May 2017: Improved Competitiveness for Conventional Coal & Gas-fired Power Plants

Tech Note January 2017:  Solving a Sub-Synchronous Rotor Vibration for a Critical Steam Turbine in a Seemingly Small, but Actually, a Large Application

Tech Note June 2016: Pressure Dam & Elliptical Bore Bearings

Tech Note Febuary 2015: Improving a Critical Component of a Fluid Drive: The Scoop Tube

Tech Note September 2014: Emergency Lube Oil Pump System based on AC/UPS/VFD Technology

Tech Note February 2013: Improved Journal Bearings for Nuclear Powered Turbine-Generators

Tech Note May 2010: Cracked Bearing Cases; 3 case studies

Tech Note July 2009: Gearbox Upgrades

Tech Note April 2009: The cause and solutions to many problems with ring-oiled bearings

Tech Note November 2007: How changes to condenser back pressure and condensate temperature can effect LP Turbine rotor vibrations.

Tech Note November 2006: Manufactured Components for a New Co-Gen Facility

Tech Note March 2005: Solutions for Problematic MHC Full Arc Controls of GE Steam Turbine-Generators

Tech Note March 2005: Solutions For Common Problems of Extension Shafts, Oil Pumps and Steady Rest Bearings For Westinghouse Large Steam Turbine Generators

Tech Note October 2003: Emergency Lube Oil Systems

Tech Note June 2003: Solutions for over-heating and vibration: two common problems of existing fluid drives.

Tech Note April 2003: Alignment Issues of Babbitt Bearings

Tech Note Dec 1998: TRI Resolution of Turbine High Amplitude Rotor Vibrations Problem

Tech Note Aug 1998: $7,000 per Megawatt-Hour ($7.00 per kwh)!!

Tech Note Mar 1998: Significantly Increase Power Efficiency

Tech Note August 1997: Extension Shaft Vibration

Tech Note January 1996: TRI Improvements Proven to Maximize Reliability of Fluid Drives

Tech Note August 1996: Reduced Reliability of the AC Power Grid

Tech Note July 1996: The 750 MW Westinghouse Turbine-Generator Improved

Tech Note June 1996: The Facts about Babbitt Bearings

Tech Note September 1995: Advancement in Design & Manufacturing of Impeller from Forgings

Tech Note April 1995: Examples of New Solutions for Old Problems

Tech Note August 1994: TRI President Announces Recent US Patents Issued to TRI

Tech Note December 1994: TRI's Mission: Past, Present and Future

TRI designs and manufacturers variable speed fluid drives for large pumps and compressors. TRI has provided retrofit packages to existing applications. Many of these units have been made to the available space envelope. In other words, they are "custom made" for the specific application.

Consider an existing application that consists of a constant speed motor driving a constant speed compressor. In such a case, it is typical to move the motor back away from the load (pump or compressor), and install a fluid drive with new flexible couplings. In some applications, the same flex couplings can be used with new coupling halves of the same design and size that are mounted onto the fluid drive input and output shafts. Then, the existing flex couplings do not have to be removed from the existing equipment.

In most cases, there is no need for the manufacturer of the pump or compressor or the driving motor to be involved. TRI has considerable expertise in the required engineering skills such as rotor-dynamics and stress analysis. If the compressor or pump is to have a new application (process fluid or pressure) then perhaps the manufacturer might be involved. We can provide drawings for the foundation modifications and your civil engineers can create the necessary foundation drawings. TRI can supply the soleplates, or we can provide soleplate specifications and you can manufacture soleplates.

TRI has many variable fluid drives in service for boiler feed pumps from 3,000 to 28,000 hp at 3600 rpm input in power plants, as well as fans at 600 rpm. 

TRI manufactures all of our products in our U.S. facility. In almost all applications, we machine the impellers and runners from forged steel. The consequence is that our equipment has a very high reliability record. Most of our fluid drives have operational records exceeding ten years between inspections.

TRI can supply complete oil systems, or we can provide the specifications for the actual hardware of the oil systems.

There is considerable energy savings that will result from application of fluid drives with large pumps and compressors. In addition, the starting operation for all components, motors, compressors, pumps, and any gears, is much easier, so life expectancy of the components is greatly increased. Removal of any discharge control valves permits improved ease of operation, and the valves that are removed no longer need maintenance. The time period that it takes to pay back the capital cost of the installation is usually measured in months. The reduced maintenance cost and increased production time (reduced downtime) should also be factored into the "benefit to cost" ratio.

Westinghouse Gas Turbine-Gearbox-Generators use bearings in the gearbox that are easily damaged if the unit is operated at low MW Load. The journals of a gear shaft contact the bearings in a manner to limit the oil flow into the bearings, causing the bearings to overheat. 

TRI used the TRI Proprietary Bearing Computer simulation program which incorporates completely non-linear time transient solution techniques to model the bearings. The existing bearings were modeled and the problems with them were identified. New TRI bearings were designed and the orientations of the split lines of the bearings were optimized. Temperature sensing instrumentation was installed to be able to measure the bearing metal temperatures in the load zones. Then the bearings were manufactured and installed with the expected satisfactory performance, including acceptable temperatures.

A 400 MW lignite fired power plant has two 6000 hp, constant speed ID Fans that were controlled by dampers on the inlet sides of the fans. Extensive testing, including gas flows and pressures, as well as electrical testing using power factor meters, provided a good “baseline” of the electrical power consumed for the fan operation at different flows and boiler conditions. Using the “test block” head – capacity plots and established fan laws, TRI made calculations as to the electrical power that would be consumed at the various load points of the test data. These calculations indicated that considerable power would be saved across the entire operating range of the fans, particularly at high loads and at low loads. Another part of the justification was that the heat exchanger for cooling the circuit oil in the fluid drives was to be located inside the Forced Draft Fan Room, thereby recovering all of the heat generated by the fluid drives in the slip process. 

With this background, a project was undertaken wherein TRI designed and built two fluid drives, one for each fan, along with a single oil conditioning system for both fans. 

This is a back to back fan arrangement, and the reinforced concrete foundations for the motors were extended to connect to each other, making the space to move the motors back so that the fluid drives could be installed between the motors and the fans. These fluid drives were made with impellers and runners with 70 inch working diameters. TRI is not aware of any fluid drive impeller/ runner size on the North American Continent that is as large or larger than these are. Due to the short space permitted, the fluid drives were built with rolling element bearings and with compact flexible couplings.

A unique characteristic of these fluid drives is that the flow of circuit oil into the element of each fluid drive is controlled in order to maintain a constant Circuit Oil Discharge (COD) Temperature. This maintains the entire fluid drive at a constant temperature of approximately 190° F and minimizes the circuit oil flow, especially at the upper end of the speed range and at the lower end of the speed range.

An unanticipated benefit was found to be this: This plant is located in a colder portion of the United States, and the ID fans are located outside. When they have been sitting for a period of time, they develop a bow and the rotors are cold. In the original configuration, when they were started, they went to full speed and had very high vibrations until the rotors warmed up and the bow relaxed. With the fluid drives, the motors and input portion of the fluid drives start and are up to speed within about 2 seconds, and then the output section of the fluid drive and the fan gradually roll up in speed. The fans can be held at low speed, so they can warm up permitting the bow to relax. Then, the fans can be brought up to speed in the operating speed range and put into service. 

Before the fluid drives were installed, the fan rotors would be brought up to max speed, and if the rotor were bowed, the vibrations would be very intense. They could be felt in offices some 200 feet away. Now, with the fluid drives, the fan rotors remain balanced as they go up in speed, and the vibrations are low, even during the start-up mode. This helps the balancing process greatly, because the bow is removed at low speeds and any vibration at high speed is due to either actual mass unbalance of the fan or deposits on the fan wheels which need to be removed.

TRI has been asked by a number of parties about the correlation between changes in LP Turbine Rotor Vibrations and changes in condenser back-pressure and between changes in LP turbine rotor vibrations and changes in condensate temperature, as well as what to do to reduce the sensitivity of the LP Turbine rotor vibrations to these changes in back-pressure and temperature.

The purpose of this case study is to address both the correlations and to provide recommendations to reduce the rotor vibration sensitivity.

Yes, there can be a correlation in each case. The way it works is as follows:

There can be, and usually is, a correlation between LP Turbine back-pressure and elevation of the cone support structures for the bearings in the LP turbine hoods. Also, there is usually a correlation between the LP Turbine condensate temperature and the elevation of the cone support structures for the bearings in the LP Turbine hoods. 

Dropping the elevation of one bearing shifts the loading on several bearings in both directions along the shaft line. In particular, the two adjacent bearings will pick up loading, but others are affected, carrying slightly less or more load. The load shift for the various pairs of adjacent bearings of a unit, for example, Bearings (4,5), (6,7), and, if they exist, Bearings (8,9), may be on the order of 1000 to 4000 lbs per mil (0.001 inches) of elevation change between adjacent bearings.

A change of loading on a bearing changes the film stiffness of that bearing: Increasing the loading increases the stiffness, and vice versa. Changing the stiffness of the bearing film of a turbine shaft can change the effective critical speed, often not much, but in the extreme, the critical speed can actually pass through the operating speed. Furthermore, almost all rotors in service are unbalanced to some degree. If a critical speed is near the operating speed and that critical speed changes, the vibratory response (amplitude and angle) at the operating speed due to the existing unbalance usually changes.  

In order to understand the actual degree of change of 1X, or synchronous, vibration in a given situation, it is helpful to plot the vibratory response on a polar plot, including the slow roll data point and the roll up data for each vibration probe of the machine. The most reliable data for understanding what is going on at each bearing in a GE machine is the “left side” data, even though the “right side” is usually the side with the larger amplitude. For a counter-clockwise rotating machine (GE), the left side is what is called the “hard side” because the thinnest film location is approximately directly in line with this probe on the lower right of the journal, and 1 mil of motion in the direction parallel to the left side probe typically represents greater vibratory force on the bearing than 1 mil of motion measured on the right side probe. The right side is the “soft side” because the journal can slide along the thin film zone, which is why the vibrations on this side are usually larger, but less important than the vibrations measured on the left (hard) side.

Typically, if the overall vibration is substantially more than the 1X vibration, then the remainder is generally sub-synchronous. If there is subsynchronous vibration, then this is important to note. A small amount of sub-synchronous is usually not a problem, but if it appears that the amplitude of the sub-synchronous component could jump to large amplitude motion, the situation should be evaluated for further action. If the unit has experienced large amplitude sub-synchronous vibratory motion, then it should be evaluated for remedial action, which TRI can offer in various forms.

There are typically two ways to support condensers. For reference, older condensers were fixed to, that is, hung from, the turbine deck and they had spring supports underneath the condenser. In this case, no flexible seal was necessary at the LP Turbine on the turbine deck. In the older units of this design, it was absolutely critical to have the condenser filled with the proper amount of water when cold alignments of the turbine-generator were made. Too much water in the condenser, and the turbine deck would be pulled down too far, and the alignment would not be right. Not enough water, and the turbine deck would not be pulled down enough, and the alignment would not be right.

The newer design, which began in the 1950s, is to have the condensers supported rigidly underneath from the basement, and to have a flexible sealing connection (dog bone) around the top of the condenser to the LP turbine at the turbine deck. The larger units, which are generally the subject of this Case Study, are made with the flexible sealing connection to the LP Turbine hood. When vacuum is drawn in the condenser, the entire LP Turbine hood is pulled down, as if a weight equivalent to (14.7 psia – actual condenser pressure in psia) times the projected area of the condenser connection to the LP Turbine (sq inches) is loaded evenly on top of the LP Turbine hood. The turbine hood and surrounding foundation drop accordingly. For an LP Turbine, the reinforced concrete (or fabricated steel) support structure must carry the LP Turbine hood, the LP Turbine rotor, and the entire vacuum loading. In addition, the ends of the turbine hood are pushed inward, and this helps to rotate the cone structures that support the LP turbine rotors. The internal support structure (struts, gussets, and the like) within each hood affects how the bearing elevation and bearing rotation are changed as a result of the forces due to the changes in vacuum loading.  

The vertical component of the change in vacuum loading in the present case is calculated as follows: When the backpressure in the condenser is on the order of 1.4 in Hg, which corresponds to 0.7 psia, the total vacuum loading on the foundation is (14.7-0.7 = 14 psi) acting over the entire area of the LP Turbine shell. If each LP Turbine shell is 20 ft x 20 ft, this is 400 sq ft or 57,600 sq inches, the total force downwards is 806,000 lbf. This force will drop the elevation of the entire LP Turbine structure. If the overall stiffness of the LP hood support structure is approximately 100 million lbf/inch, then the 14 psi pressure will cause the turbine deck to drop by 0.008 inches (8 mils).

Dropping the backpressure from 1.4 inches Hg (0.7 psia) to 0.8 inches Hg (0.4 psia) increases the downward pressure on the Hood by 0.3 psi, which corresponds to another 17,280 lbf downward loading. This 0.3 psi change of loading would drop the turbine deck by an additional 0.17 mils.

Each of the bearings of an LP Turbine is in a structure called a cone. It is, in effect, a tunnel that extends out into the LP Hood. These cone/tunnel structures are designed to move the bearings toward the center of the LP Turbine rotors, reducing the bearing spans of the LP Turbine rotors. When vacuum is drawn, the hood changes shape and each cone/tunnel structure rotates. 

A change of temperature can cause a significant change in the shape of a large steel structure, such as an LP hood. For instance, a 10 degree F change in a steel bar that is 16 inches long will change the length by 0.001 inches. If a steel structure that is 48 inches in length is subjected to a temperature change of 30 degrees (105 – 75) deg F, it will change length by 0.009 inches. 

Experience over many years indicates that it is very difficult to know how the bearings and the shaft line are going to respond to a change in vacuum (back-pressure) and/or to a change in temperature of the LP hood before a machine and its mounting structure are built. Similar units react in different ways. How the LP hood is constructed including what gussets exist, how the hood is supported by the foundation, and how the foundation is built (concrete or steel) affect how the bearing elevations will change with a change in vacuum and/or condensate temperature. 

Usually the foundation is a reinforced concrete structure down to bedrock or to substantial pilings, but some foundations are steel structures. The long vertical piers under the bearings are cooled and change length when the ambient temperature changes, in an amount as described above. Some columns change length more or less than others because some are more exposed to radiant heat from steam pipes than are others, and some are more exposed to changes in ambient temperature than others. Some units are so sensitive to ambient air temperature that opening a big door in cold weather will cause the vibrations to change almost immediately, and in some extreme cases, the sound of the machine vibrations will change, and will do so in a repeatable manner.

The alignment of the LP turbine rotors relative to each other and to the adjacent turbine or generator rotors is often intentionally adjusted from time to time by turbine engineers, so that at normal operating temperatures, the bearings are fairly evenly loaded as represented by the bearing metal temperatures. It is imperative to retain plant records of what alignment conditions provide the best operating conditions, and to use the latest records of what works best for each unit in the process of aligning the rotors for that unit during each subsequent outage.

In 1973, I took a considerable amount of test data on a 500 MW tandem compound GE LST-G which showed the following trends. When cold and when no vacuum was drawn, the LP Turbine Bearing 5 was substantially unloaded. As the temperature in the condenser increased, the LP hood expanded, raising Bearing 5. When the unit was at normal operating temperatures, the bearing metal temperatures evened out showing that the loading on these two bearings evened out.

On the other hand, other GE units of a slightly larger size have Bearing 4 unloaded and Bearing 5 loaded when cold. Yet, at operating conditions, the bearing metal temperatures are approximately the same.

In any case, it is typical that the largest mismatch between couplings in cold conditions along a GE tandem-compound train occurs between the last IP Bearing and the first LP Bearing. In other words, the first LP Bearing sees more variation in loading than any other LP turbine Bearing. The last Turbine bearing, adjacent to the generator, also sees variation in loading, but usually not so much variation as the first LP Bearing experiences. 

It is difficult to try to modify the hood structures in such a manner as to reduce the sensitivity of bearing loading to changes of vacuum condition or to condensate temperature. If these changes become concern items on a continuing basis, then the least costly options are (a) to change the first LP Bearing from an elliptical bearing to a tilting pad bearing, such as a TRI Align-A-Pad ® Bearing, and/or (b) to use a variable speed pump to control the circulating water flow rate to maintain uniform condensate temperature and backpressure.

Summary of Recommendations:

  1. Because most of the GE LP turbine bearings in the original configurations are marginally stable, that is, they are not far from experiencing sub-synchronous vibrations such as “oil-whip”, it is very helpful to have the LP Bearings mounted as rigidly as possible in the cone structures, or standards, as the case may be. 
  2. For those LP bearings that are adjacent to the IP turbine or to the generator and experience substantial elevation changes, and have demonstrated any tendency toward sub-synchronous vibrations, consideration of changing to a tilting pad bearing such as the TRI Align-A-Pad ® Bearing is appropriate.
  3. The standard GE elliptical bearings can be modified using a TRI proprietary design method in a way to improve the stability of the bearings while keeping the original Babbitted bearing length. In some cases, converting to shortened elliptical bearings is advantageous. In other cases, the bearings should not be shortened because the Babbitt becomes overloaded, and in this case, other design modifications can be made by TRI proprietary methods to reduce the amplitudes of synchronous rotor vibrations as well as to improve stability (resistance to sub-synchronous vibrations).
  4.  It is very important that the turbine engineers maintain accurate records of what alignment works for each machine. Trying to follow the OEM recommendations in the original mechanical design data (instruction) book is not necessarily advisable because this data may have been written before the unit was actually built and does not take into consideration how the unit is being operated, peculiarities of the foundation design, whether it is in indoor or outdoor unit, the range of ambient temperature conditions to which the unit is exposed, or what has been learned from this unit about what makes it work best. Bearing metal temperatures, vibratory characteristics, orbit shapes, and wear patterns should be used to adjust the alignment from time to time to optimize the performance of the machine. In many cases, bearing designs have been changed to permit a wider tolerance on the alignment data that is used. This is a clear benefit of using the TRI Align-A-Pad ® tilting pad bearings in places that are susceptible to a range of alignment conditions during operation, such as result from high temperature conditions of the standard when at high load and cooler temperature conditions when at low load.
  5. Where over-cooling of the condensate has occurred with the normal operating conditions for the circulating water pumps, it is appropriate to consider variable speed motors. Under certain circumstances, two-speed motors can be used. In extreme circumstance, turning on or off the circ water pumps may be appropriate to control the cooling of the condensers. Exercising any one of these options may help to optimize the cycle efficiency under various plant conditions and/or ambient conditions.

Because most Large Steam Turbine-Generators were built to operate at or near full load, and because capital costs were (and are) always a critical factor in new equipment, most LST-G units were made with a certain number of constant speed circulating water pumps, and these were intended to be on all of the time, and not cycle on and off. Nevertheless, some units have been modified to have two speed condenser cooling water pumps. For some units, variable speed circulating water pumps are being considered. Incidentally, in some cases, variable speed pumps are being considered to minimize water removed from a river primarily for external reasons, but would provide the possibility of cycle efficiency optimization.

There is a compromise in establishing the preferred condenser back-pressure: In almost all cases, the colder the cooling water, the lower the back-pressure, and the more MW load that is generated, with all other conditions being the same. However, the colder the condensate, the more heat that is required to heat the condensate to make the steam for the turbine. The objective should be to cool the condensate no more than is necessary to optimize the efficiency of the cycle. For those units that are operating at maximum firing rate, over-cooling the condensate will actually reduce the MW generated.

An issue to be considered in selecting an option for varying the circulating water flow is this: The motors for circulation water pumps are huge, and these motors and the associated switchgear typically were not designed to be started often. Stopping one of these motors and restarting it in a cyclic manner is not wise, even if it might optimize the cycle efficiency. 

It is not often that an FD Fan, ID Fan, BFP, or other large auxiliary is forced out of service. Consequently, when the MW load is dropped for a period of several days to repair one of these items, it might be worthwhile to take a circulation water pump off, so long as the condenser function remains reasonably uniform for all of the condenser and LP Turbine sections.

damaged bearing pad

Problem: A Journal and mating Babbitted Bearing are both found to be significantly damaged. The situation addressed here is focused on a journal that is grooved, scored, or severely pitted. Causes may include a large solid particle in the lube oil, loss of lube oil, or extensive pitting from electrolysis. In severe cases, the journal may be damaged to a radial depth of 1/8 inch or more. 

Solution:  TRI offers a “turn-key solution” wherein the plant places one contract with TRI to provide the services to remachine the journal and to refurbish the bearing to suit the new journal size.


High Powered Variable Speed Fluid Drives are used to provide power to Boiler Feed Pumps and Fans. Each of these Fluid Drives has an input shaft assembly that rotates at the speed of the input power source, which may be an electric motor or a steam turbine-generator that operates at constant speed. The output shaft assembly rotates at a variable speed, typically controllable from 20% to 97.5% of the input shaft speed.

The typical design of a variable speed fluid drive uses an input rotating assembly that is coupled to and rotates with the speed of the driver (motor or turbine-generator). The output rotating assembly is connected to and rotates with the driven load, a pump, fan, or compressor.

The input rotating assembly consists of an input coupling, a shaft supported by the two journal bearings and a thrust bearing, and a fluid drive element that consists of an impeller and a casing that surrounds the impeller and a runner, all rotating together.

Read more ...

The "shorted turns" of a generator field caused uneven heating of the rotor, which caused the rotor to bow and have high unbalance. The bow in the rotor caused very high amplitude synchronous (at running speed) rotor vibrations. These high unbalance forces effectively unloaded the bearings. Because the bearings were cylindrical bore, when unloaded, they would develop sub-synchronous (near first critical speed near 800 rpm) vibrations. The vibrations at mid-span of this 65 ton rotor were calculated to be on the order of 0.140 inches peak to peak.

Read more ...

Machinery Problem Solver

Below are some of the common problems that TRI has dealt with over the years. The TRI Machine Problem Solver is a tool to help customer identify problems and locate solutions.

  1. Begin by clicking on one of the listed problems in the left column. This will highlight (turn blue) some of the possible causes.

  2. From the middle column, select one of the highlighted "causes". The "cause" will turn red and the possible solutions will be highlighted in blue.

  3. Click on one of the "solutions" to see more information about the topic.

TRI Solutions
Click a solution to see how TRI can help solve your problem

Finite Element Analysis (FEA) Consulting Services

TRI provides engineering services such as Finite Element Analysis (FEA). Our engineers have years of experience in the analysis and manufacturing for mechanical equipment We use commecial and proprietary software to solve complex simulations.

Contact us to talk to an engineer about FEA and other engineering servcies

Rotor Design

TRI uses advanced proprietary modeling software to simulate the dynamics of turbomachinery and rotors. This software has been used over the years to solve many rotor vibration problems. By analyzing the bearings, support system and rotors as a system, TRI can locate design problems and consult with our customer to make improvements to their equipment.

TRI has a manufacturing facility in Lionville, PA that can manufacture many of the products we design. There are some rotors that we can not handle. Generator or turbine shafts for many power plants are beyond the machine capacities of our current equipment. In these cases, we work with our customers and outside manufacturing sources to design and implement the solution.




Coupling Design

It is possible to have two satisfactory machine components fail because of the coupling that connects them.

The coupling between machine elements must be properly designed, installed and maintained. A coupling should be designed to withstand the torque required for the application while accommodating misalignment between shafts. Because machine components move due to temperature, dynamic bending and bearings wear over time, some misalignment must always be accounted for. A coupling design should be able to handle angular, axial and radial misalignments and the amount of misalignment is a function of many factors.

TRI has experience with many applications that use all forms of couplings such as gear coupling, diaphragm coupling, spindle couplings and disc couplings. We can help you to analyze your system and determine your coupling requirements.

Types of equipment with TRI Bearings and Fluid Drives

Steam Turbine-Generators, 3 MW to 1300 MW, fossil fired or nuclear fossil fired or nuclear (GE, Westinghouse, Allis-Chalmers, Alstom, ABB, Siemens, Hitachi, Mitsubishi, others)

Mechanical Drive Steam Turbines

Hydro Turbine-Generators Includes Dual Rotation Pump-Storage Units

Gas Turbine-Generators

Combined Cycle Turbine-Generators

Fluid Drive Transmissions, Includes Geared, Variable Speed Units (TRI, American-Standard, American Blower, Voith, others)

Motors, Synchronous and Induction

Synchronous Condensers, Rotating Includes Start-up Packages

Reactor Coolant Pumps and Motors

Gear Boxes

Pumps, Boiler Feed

Pumps, Vertical

Fans, Centrifugal and Axial


Compressors, High Speed

Hot Gas Expanders

Free Power Turbines

Babbitted Bearings of all Types

Oil Systems

Hydrogen Seals and Seal Oil Systems

Shipboard Applications

Aeroderivative Engine Driven Generators

Fluid Drives for Diesel Engine Driven Equipment (Rock Crushers, Wood Chippers, Road Millers)

TRI Interactive Application

This is an interactive chart that help to select the proper fluid drive for your application. The Circuit size is the working diameter of the fluid drive impeller and runner.

U.S. Patents issued to TRI Transmission & Bearing Corp.

Patent 4,867,006: Rotating Shaft Mounted Actuating Mechanism

Patent 5,144,862: Rotating shaft mounted actuating mechanism

Patent 5,188,170: Rocker connection

Patent 5,207,903: Filter stand assembly

Patent 5,303,801: Brake assembly having an adjustable yoke

Patent 5,315,825: Oil system for constant input speed fluid drive

Patent 5,331,811: Fluid drive with ruggidized impellers

Patent 5,438,755: Method of making a monolithic shrouded impeller

Patent 5,505,662: Quick disconnect flexible geared coupling

Patent 5,573,374: Monolithic shrouded impeller

Patent 5,610,500: Method of converting turbine driven generator into a synchronous condenser

Patent 5,886,505: Apparatus and method for bringing on line a large synchronous condenser that cannot be started by an across the line start

Patent 6,712,516: Bearing spring plate pedestal

Patent 6,769,248: Fluid coupling for mobile equipment

Patent 7,004,626: Fast Acting Thermocouple

Patent 7,171,870: Geared fluid drive with parallel start-up capability

Patent 7,237,958: Bearing stiff plate pedestal

Patent 8,028,526: Geared Boiler Feed Pump Drive

Patent 9,841,055: Vertical Guide Bearing Improvements

A review of past projects at TRI

TRI solved some very perplexing problems over the years. As is often the case, the first step is to identify accurately what the problem is, and then to design options to solve the problem. The following case studies are among many that have been solved by TRI. Should you have a similar problem, or a new problem, that is related to high amplitude vibrations – synchronous (“1-X”) or sub-synchronous, bearing damage, and/or fluid drive and flexible coupling issues, please contact TRI. TRI is interested in addressing such problems for our clients.

Often a client realizes he has a maintenance problem, and has been living with it for years believing that “that is just the way it is”. In most cases, TRI can identify the problem, and work with the client to bring TRI’s engineering and manufacturing skills to bear on the issue, and resolve it in a timely and cost-effective manner. No machine is too large or too small for us.


Case Study: Unevenly Heated Rotor

Case Study: Turbine-Condensate Correlations

Case Study: Repair of Severely Damaged Journals and Bearings

Case Study: Gear Box Bearing Upgrades

Case Study: Babbitt-Copper intermetallic compound layer

Fluid Drives

Case Study: Vibration Patterns Expected for Variable Speed Fluid Drives

Case Study: Fluid Drive for ID Fan

Case Study: Fluid Drive for Large Compressors and Pumps

Other Case Studies

New Emergency Lube Oil Pumps