On-site and off-site balancing:
If your turbine-generator encounters excessive vibration and you want assistance, please call or e-mail and give a brief description of your problem. We are equipped to help solve any vibration-related issue a customer may have.
Most Customers have at least one employee on-site, or in their system, that is responsible for monitoring of vibration and predictive/preventative maintenance, whose familiarity with the turbine-generator will usually depend on how much involvement they want with the balance work.
For the above reason we will furnish service to whatever extent you require:
For instance, a customer may be in a situation where they want nothing more to do with it other than comply with the operational testing procedure and shut down/restart the unit for balance weight installation. Full service balance work is expensive in the first place and even more if the work is done on overtime, which is often the case.
The next customer may feel very comfortable with recording the peak/phase vibration data using the plant's equipment (and making and installing their own balance weights) and pay nothing more than a minimal charge for data evaluation and balance shot calculations as their situation requires.
For those of you out there that have units that frequently require balancing of data review (longer multiple-cylinder units over 600 Mw, or with Westinghouse LP BB73 or similar GE larger frame equipment, double exciters, etc.) you might want to consider increasing the degree of involvement in the data collection and balance work by the individuals at the plant.
If you want to send in data for the purpose of getting an idea of what's causing your problem and what's necessary to correct it please submit all of the following information and someone will respond as soon as possible (Call 770-975-3123 if you have an emergency):
1. Plant & unit number
2. A description of the vibration problem
3. Data collection procedure used (if data is included and you want to know whether or not balancing is a solution to your problem):
3.1 Frame of reference information
3.2 Direction of observed shaft rotation
3.3 Polar coordinate system nomenclature (is 90 degrees right or left of zero?)
3.4 What type of equipment you need, and the date of its last calibration.
4. All data submitted for balancing assessment evaluation must include, at a minimum, the vibration data taken from the turbine-generator supervisory instrument panel, filtered (peak/phase) and with filter out (meter display). You will be contacted if any additional data collection is required.
4.1 If the meter reading (unfiltered) is over 15% above the amplitude of the running speed frequency of the vibration at any measurement point then you need to submit a spectral analysis using preferably a CSI 2115 series datalogger or similar equipment.
4.1.1 All CSI or similar spectral data should be submitted in graphic display, using Hanning Window format and the following settings:
Horizontal axis: 10 to 500 Hz, use linear scale
Vertical axis: Displacement (in mils), or velocity (in inches per second), on a log 10 scale, using the "automatic" range settings of the spectral analyzer:
You should report displacement readings for data collected with proximity probes, Bently-Nevada dual probe fitted seismic transducers, velometers or any shaft rider data you have that was collected with velocity transducers. You should report all accelerometer data you take, using velocity readings.
Kro-Magnum LTD, P.O. Box 578, Kennesaw, , US, 30144. Tel: 770-975-3123; Fax: 770-975-3123.