ENERGY-TECH • January 2012

At a power generating station in Florida, a severe electrical fault caused such extensive damage to a 40 MW gas turbine-driven generator that a complete replacement of the generator stator was required. An on-site spare generator core was available, but needed the faulted generator’s bearing support brackets to be installed to make it complete. As this combination of bearing support brackets and generator frame would be considered a “mismatch”, it was decided that the position of the bearing supports should be verified to ensure proper centralization of the generator’s field (rotor) relative to the generator core.

The primary objective was to accurately determine the centerline position of the generator core and position the bearing support brackets so that an equal radial air gap between the rotor body and core laminations would be obtained during generator operation.

Exact positioning of the support brackets was accomplished using specialized tooling such as the CENTRALIGN ULTRA laser bore measurement kit and the ROTALIGN ULTRA laser tool from LUDECA.

Read entire article Internal component alignment of 40 MW A.C. generator by our customer Chuck Hildebrand, Dynamic Balancing Company.

Fault frequencies are very important in vibration analysis, because they allow the analyst to correlate vibration data to specific components in the equipment that may be in some stage of failure (equipment faults). Fault frequencies change with any adjustment in the speed of the equipment being monitored. Most modern vibration data collectors and software will automatically re-calculate the displayed fault frequency information as the rotational speed of the equipment changes. Component information (bearing information, gear information, etc.) is required to calculate and display the fault frequencies of specific components in machinery. 

It is important to create fault frequency setups at the beginning of a vibration analysis program. Not doing so will affect the overall success of the vibration analysis program.

Come Learn with Us! Training for shaft alignment, vibration analysis and balancing with our tools is scheduled throughout the year at our Miami, Florida Training Center or can be scheduled on-site at your facilities. In addition, we are pleased to be working with education and consulting services firms such as Pioneer Engineering, People and Processes and Mobius Institute to bring you additional maintenance and reliability training resources.

VIBRATION ANALYSIS using VIBSCANNER and VIBXPERT

• 4-Day VIBXPERT
  April 17 – 20, 2012
  June 19 – 22, 2012
  

BALANCING

•  May 1 – 3, 2012

VIBRATION ANALYSIS Training and Certification – Hosted by Mobius Institute

• Mobius ISO Category I VIBRATION Training & Certification
  April 23 – 26, 2012
  Details

SHAFT ALIGNMENT using OPTALIGN and ROTALIGN

• 4-Day OPTALIGN PLUS and ALIGNEO
  May 8 – 11, 2012
• 4-Day ROTALIGN PRO
  April 24 – 27, 2012
  June 19 – 22, 2012
• 4-Day ROTALIGN ULTRA
  April 24 – 27, 2012
  June 19 – 22, 2012
• 4-Day OPTALIGN SMART
  May 8 – 11, 2012

BORE ALIGNMENT using ROTALIGN

• 2-Day BORE ALIGNMENT
  May 1 – 2, 2012
  June 26 – 27, 2012

FLATNESS MEASURING using ROTALIGN with LEVALIGN

• 2-Day LEVALIGN (FLATNESS)
  May 3 – 4, 2012
  June 28 – 29, 2012

MAINTENANCE Training – Hosted by People and Processes

• Maintaining Equipment Health with PM, PdM & CBM
  May 14-15, 2012
  Details
• Skills for Maintenance Leadership and Supervision
  May 16-17, 2012
  Details

 Reserve your space now! Call 305-591-8935 or email us.

When aligning a vertical flange-mounted machine, it can be helpful to tweak the flange configuration in your laser alignment system to take advantage of different shimming alternatives. For instance, if the OD of the flange is larger than the diameter of the mounting bolt circle, a good laser system will compensate for this by taking into consideration that when shimming your pivot point is not the bolt circle but the flange OD. Thus, all shimming corrections will be positive.

However, if you already have shims at all the bolt positions, you could take advantage of the opportunity to minimize the required shimming corrections by forcing the smallest correction position to be zero. Do this by entering a distance for flange OD as being equal to your bolt circle. Of course the best laser systems already allow for all the different shimming alternatives (positive, negative and zero sum options) right in the software, so you don’t have to use this trick.

Back in July 2011, ArcelorMittal Point Lisas, Trinidad awarded TOSL’s Predictive Maintenance (PdM) Department with a one year contract for Reliability and Condition Based Monitoring. It was the first time a process like that would be implemented at ArcelorMittal. The contract is being executed by our Senior PdM technician, Mark Dwarika, and PdM technicians, Samir Khan and Ramon Rabathaly.

TOSL’s PdM Department is currently facilitating ArcelorMittal with Reliability and Condition Monitoring Services, inclusive of vibration data collection and analysis, lube-oil sampling and analysis, as well as infrared thermographic inspection of the DR1, DR2 and DR3 plants. Over the short period since the commencement of the contract the reliability of the facility has improved by approximately 8% —surpassing expectations.

Karth Arthur, Assistant Engineering Manager at ArcelorMittal quoted that: “It gives me great pleasure to recommend TOSL Engineering Ltd to any firm. I have worked with TOSL from March, 2010 to present. During this time they have provided condition monitoring services to our five plants. These include Vibration Analysis, Thermographic Analysis, Electrical Signature Analysis (ESA) and Oil Analysis. The quality of work has been of the highest standard and their reports have been clear and concise. With these services we have increased our availability by 15% and reliability by 8%. I recommend them with enthusiasm, and we will continue to utilize the services of TOSL Engineering Ltd”.

Early fault detection of rotating and static equipment components is a key factor to improving the mean time between failures (MTBF). The PdM technicians are now based at the ArcelorMittal as a fully incorporated faction of the facility. The interaction between the facility management, engineers and TOSL personnel have improved the plants reliability to where failure of components monitored and corrections made based on recommendations and consultation have decreased drastically. Monthly PowerPoint Presentations, departmental meetings, as well as equipment condition assessment reports, updating and emergency action plans on critical equipment are also a major role that the technicians are either responsible for or play a role in.

Repairs on equipment are facilitated by ArcelorMittal’s respective maintenance departments, but it is also the PdM technicians’ responsibility to oversee and, if necessary, recommend changes to procedures in place. Overall the actions and recommendations collectively outline the basis of a functional Reliability and Condition Monitoring Program with improvements noted.

Congratulations to ArcelorMittal and TOSL Engineering Ltd., LUDECA‘s representative in Trinidad & Tobago, for their Reliability Achievements.

Unbalance occurs when the rotor’s mass is no longer at the center of rotation.  Unbalance can be caused by many factors:

• Assembly error
• Machine tolerances
• Eccentric components
• Wear
• Corrosion
• Thermal distortion
• Mechanical distortion
• Material buildup
• Bent components
• Broken components

Many things can prevent the successful correction of unbalance.  Equipment resonance, bearing issues, product buildup and many more equipment problems can prevent a successful balancing  job from being completed.  All Equipment defects should be corrected before attempting to balance equipment.