In-place stationary shaft machining allows MD&A to repair damaged journals, collector rings, and seal areas without removing turbine and generator rotors from the unit. The compact setup easily fits under LP hood radii to allow for machining along the complete rotor train.

Saving you time and money, this capability eliminates unnecessary downtime. Advantages include:

Cost Effective:

• Reduction in crew size, as disassembly is limited to removal of outer bearing cover and Babbitt bearing.
• Shorter schedule duration.

Lay down area reduction:

• Portable lathes occupy valuable space on a turbine deck, whereas stationary journal equipment requires only three standard gang boxes.
• Repairs can be performed with the rotor left in the unit.

Time Constraints:

• Most stationary journal repairs can be completed in three to four shifts, start-to-finish.
• Reduces schedule impact by eliminating disassembly & reassembly of the steam turbine.

Our technicians have 20+ years of experience with in-place stationary shaft repairs.

MD&A experts first perform a complete Foreign Material Exclusion (FME) of the bearing standard to ensure metal shavings do not enter the lube oil system and the packing gland is sealed to prevent intrusion of foreign contaminants.

Diametrical measurement inspections and concentricity sweeps are then completed, and findings are discussed with the customer prior to machining.

Next, the honing and polishing process is performed – surface finishes up to 2Ra are achievable. The concentricity of the journal is checked throughout honing process to maintain centerline.

The machining process allows for a perfect blend of newly machined diameter to the existing radius.

We also offer Babbitt bearing restoration in our facility upon completion of shaft machining, to accommodate for the new diameter.

MD&A can currently accommodate shaft diameters from 9 – 24 inches with additional sizes supported when the schedule allows. This new service increases our ability to respond quickly to our customers’ ever-changing needs.

MD&A continues to invest in new capabilities that enable us to expand our quality service and repair offerings. Our commitment to excellence has earned customer trust for all turbine-generator needs. We focus on delivering consistent quality and value with fast response, superior communications, and innovative solutions.

For additional information, call MD&A’s Turbine-Generator Repair Facility today at (314) 880-3000 or use our Contact form.

The post In-Place Stationary Shaft Machining Capabilities appeared first on MDA Turbines.

The original work scope involved electrical testing of the generator rotor and stator, along with the removal of the retaining rings to inspect the insulation and blocking under the rings.

Upon inspection of the stator, greasing was observed but more imperative, about 80% of the wedges were found to be loose. MD&A experts recommended the replacement of the wedges, including an updated design to an increased number of shorter wedges with a top ripple spring (TPS) system to allow for more uniform compression. The customer accepted this recommendation.

Because this was a new and improved design and there was a very limited outage window in which to perform the work (24 days), original wedge samples were hand-carried internationally across the border to MD&A’s wedge supplier in the USA. MD&A and the customer coordinated logistics to have a customer quality engineer hand-carry the samples to the manufacturing facility.

Samples were delivered for the start of manufacturing within 24 hours despite a snowstorm that canceled connecting flights. The customer representative, stationed at the manufacturing facility, monitored production and quality and reported daily status to the on-site team.

The wedge samples were measured and the newly designed wedge drawings were produced using CAD/CAM software and passed the manufacturer’s engineering review process within hours.  A group of wedges were manufactured the next day and were delivered on-site for installation within 48 hours.

In parallel with new wedge manufacturing, MD&A experts were repairing the damaged semi-conductive coating on several bars.

Once the initial batch of wedges was received on-site, they were fitted and minor adjustments were performed.  This information was communicated to the wedge manufacturer and incorporated in engineering drawings & remaining wedges.

The wedge manufacturer made and shipped the replacement wedges in batches to allow MD&A to continuously install new wedges while performing other work in parallel, increasing productivity.  The collaborative coordination between the customer and MD&A continued as the last batch of wedges was received on-site.

Upon inspection of the generator rotor, it was discovered that the blocking under the retaining ring was cracked.  Normally, repairing the blocking would require the removal of the retaining rings.  MD&A’s generator specialists developed a method of repair to the blocking that could be performed with the rings in place.  This was desired, as removal of the retaining rings can often require the replacement of the ring insulation prior to reassembly.

The customer accepted MD&A’s recommendation and repair method.  The cracked blocks were replaced to the customer’s satisfaction. This saved the customer both schedule time and cost. The customer commented that the MD&A generator technician that performed the work “was a true artist” as he shaped the blocking to fit.

This project was completed within 21 days, and below budget.

MD&A is known for our technical expertise, responsiveness, and commitment to customer service.  Our willingness to offer pragmatic solutions and our ability to marshal the required resources quickly is well recognized and respected within the industry.  In addition to the project described above, MD&A’s capabilities include the overhaul, repair, and supply of parts for steam or gas turbines and generators worldwide.

Call MD&A today for any generator repair at +1 (314) 880-3000 or use our Contact form.

The post Emergent Generator Re-wedge appeared first on MDA Turbines.

First unit:  This was a major outage and generator test & inspection. In addition, this unit was retrofitted with a new rotor, bearings, and steam path components that required machining, including installing and fitting new nozzles. MD&A provided Project Management, Technical Direction, a Controls Engineer, and a Vibration Engineer for startup and balancing.

In order to maintain the outage’s schedule, MD&A worked closely with the OEM’s engineering team to ensure that the new retrofitted components were installed correctly and to resolve any technical or engineering issues quickly. MD&A’s knowledge, experience and our skilled project manager and technical adviser resulted in this successful outage.

MD&A’s Repairs Division personnel performed onsite final machining of the nozzle plates and their associated shell locations. Our repair technicians also performed on-site diaphragm repairs.

MD&A also provided a packing installation specialist to install and final machine new upgraded packing.

To support the major outage schedule and expedite the on-site work, MD&A sourced equipment locally to overcome the time required to get the specialty tooling and equipment trailers through Colombian customs.

This unit was started up without incident and has been operational since.

Another unit: MD&A provided Project Management and Technical Direction on a Steam Turbine Generator (STG) major inspection and performed Generator testing and inspection. MD&A also provided a balance engineer, Topless Alignment®, and start-up commissioning support through our Turbine and Generator Controls Division.

The steam turbine had not been inspected for 23 years. Using MD&A’s pre-outage planning processes and experience, the execution team immediately started working to identify & mitigate potential project risks. One example was special tooling, which needed to be located and prepared for use.

After the balancing work was performed, the machine was started up smoothly, synchronized, and brought to full load. This unit has been operational without issue since this start up, after 23 years without maintenance.

Another unit: MD&A worked this unit and the one above in parallel to minimize the impacts on schedule caused by the emergent work.  MD&A provided Project Management, Technical Direction, and balance support at start up for this valve, bearing, and turning gear inspection.  MD&A also supported conversion of the Mechanical Hydraulic Controls (MHC) to Electro-Hydraulic Controls (EHC) (with the exception of the mechanical overspeed trip, which was retained).

This unit was started up without incident and has been operational ever since.

Last unit:  This major outage was similar to the other unit’s scope including valve, bearings, and turning gear, but was expanded to include generator bearings and coupling alignment. As was the case for all units, a lube oil flush was performed. For this start up, vibration data was analyzed remotely by MD&A, saving the customer the mobilization cost for the vibration specialist.

This unit was also started up without incident and has been operational ever since.

Epilogue: These successful outages demonstrate the full-service capability, responsiveness, and flexibility that MD&A can provide. The customer was very appreciative of our flexibility and our ability to adjust our execution plan as required to support the overall outage plan.

Throughout the U.S. and around the globe, MD&A provides responsive support, thorough communication, and excellent execution, making MD&A the service provider of choice for numerous power generation asset owners who desire a one-stop solution for all of their turbine-generator needs.

Call MD&A today at +1 (518) 399-3616 or use our Contact form.

Also be sure to sign up for our MD&A Insight e-newsletter delivered quarterly.  Fill in sign up form on the left-hand side and hit SUBSCRIBE!

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