Problem: Wind turbines by their nature are located in remote locations. Daily monitoring of systems is often an impractical solution.
Establishing a benchmark trend for typical wear debris on a good operational gearbox and then monitoring any change is critical and has been identified as an area for
assessment by our client.

Solution

To set up a realistic trial on a recognised 18 month old gearbox within an existing wind turbine utilizing the TechAlert 10 inductive oil debris detection sensor. In
addition a TechAlert 20 magnetic sensor. This would provide comprehensive data regards the type, size and value of the non ferrous and ferrous debris within the
gearbox lubrication system.
TechAlert 10 and TechAlert 20 placed insitu
.
Manifold, pump, filter and connection hoses
Trials

The test system consisted of a TechAlert 10 and TechAlert 20 connected, in series between the pump and filter of the gearbox off-line filtration unit.
A cable was run the length of the tower to provide power to the condition monitoring system and also serial data lines so that the sensors could be polled from a laptop at the base. The data was sent to and stored in a laptop for later analysis. The software also displaying a real-time graphic of the current wear debris trend.
The laptop time was synchronised with the turbine SCADA system to allow both sets of data to be compared for wear trends during particular operating parameters.
As a simple stand alone demo system retrofitted to an existing turbine data had to the collated manually. In live systems the data is integrated into the turbine management
systems.

Ferrous Particle Plot
Non Ferrous Particle Plot
Results

Weekly manual checks were carried out and an increased volume of debris was detected and recorded. In light of these results, the wind farm operators performed
a magnetic sweep of the gearbox sump. A quantity of wear debris was found and further investigation was warranted.
An endoscope inspection was performed on the bearings and gearbox by a factory specialist .This revealed that the intermediate bearing was damaged whilst the low and high speed bearings were still in good condition. The gearbox specialist indicated that normally this early level of wear would not have been detected and if it had not been discovered, the wear being generated would have probably caused damage to the other bearings and gearbox.
It should be noted that no other particular events or alarms were raised to even suggest that anything could have been wrong with the gearbox

Conclusions
The on-line condition monitoring of the wind turbine gearbox proved successful, giving the only and early warning that:
•Increased amounts of wear debris had been found in the
gearbox.
•No other parts of the gearbox had yet been effected by the
increased wear debris, reducing repair costs.
•The gearbox could be left running whilst scheduling
and planning for the downtime and maintenance costly
downtime and repairs was prevented.
Bottom Line Benefits
The early detection of bearing and gearbox wear on wind turbines has direct impact on a companies maintenance costs and production.
• saves on replacement gearbox
• reduced specialised equipment costs such as crane hire
• replacement costs
• managed downtime with scheduled repairs
• loss of revenue minimised
• considerable ROI
Established in 1999 Macom Technologies Ltd is a leading developer of condition monitoring systems. Our continuous investment in sensory technology enables us to design, test and manufacture a range of products that provide industry effective asset management and pro active maintenance.
Our real time, on-line, digital sensor technology helps reduce unplanned downtime and life cycle costs; in addition to improving the performance and increasing the lifetime of process machinery.

This case study was compiled by Stephen Skelton of
Macom Technologies Ltd
Macom Technologies Ltd.
43 Watt Road
Hillington
Glasgow
G52 4RY
Scotland
UK
Tel. +44 141 882 0077
Fax. +44 141 882 0770
E-Mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Web:
www.macom.co.uk
Real time online sensor technology benchmarking for best practice
Abstract
Increased levels of wear debris particles were detected by a Macom TechAlert, on-line condition monitoring sensors.
Following on from this full a magnetic sweep of the gearbox sump was carried out which confirmed wear debris at the bottom of the sump. Further detailed investigation showed only the intermediate bearing rollers where wearing. The damage and therefore the failure had been caught early enough so as not to cause further damage to the remaining bearings and gearbox.
A scheduled repair was carried out with a minimum loss of revenue.
“Macom TechAlert benchmark trial has proved
that real time online wear debris monitoring
is a baseline requirement for all new turbine
developments.”
Mr. Graham Berry.
European Operations Manager. Airtricity.