Ongoing Inspections of Wind Turbines create long-term Value

When we carry out inspections, all deviations that can create challenges and downtime are identified and analyzed. For example, oil leaks in the vital parts of older wind turbines can be fatal to the lifetime.

What is it

Inspections uncover and analyze all deviations that can cause problems and downtime.

What did we do?

Conducted a series of inspections and identified critical needs for improvement. This ensured wind turbine lifetime extension.

What was the outcome?

The result was fewer outages, fewer repair costs and service providers living up to their quality requirements.

Inspections done by Momentum

At Momentum we carry out regular inspections of wind turbines for visual, electrical and mechanical deviations. One of the problems we often observe, is oil leaks. An oil leak in e.g. a gearbox will lower the oil level below nominal level. This is never recommended. On new generations of wind turbines, alarm parameters ensure that the turbine will auto-stop at major leaks. But this is not always the case for wind turbines of older date.

For older wind turbines without oil level measuring systems, problems that are not identified in due time can be fatal. Low oil level can result in a defective gearbox and worst-case scenario is destruction of the turbine. If oil furthermore leaks into the ground, costs related to removal and cleaning of contaminated soil must be expected.

In several other cases we have observed problems and errors in the rotating electrical components due to inadequate service and maintenance. On rotating components, we always investigate if cleansing of coal dust has been done. Accumulation of coal dust in the rotating components can cause short-circuit in the tracks. We also check if the coal that constitutes the component connection complies with the minimum dimensions required by the manufacturer’s instructions.

Short-circuits in rotating components will cause immediate shutdown of the wind turbine, requiring the component to be completely replaced. In most cases this is a costly affair.

Observed Deviations

When we analyze and review damages, we also assess the possible consequential damage to other components. Furthermore, we estimate the remaining component lifetime and identify actions that should be taken in order to minimize future downtime.

Momentum’s customers are kept in the loop throughout the whole process. All the way from our review of inspection results, to technical advice and dialogue with service providers.


"The inspection ensured that we became aware of challenges that could have resulted in long-term downtime. Momentum made a plan, implemented an effective repair process and continued smooth operation of the wind turbine"

An Example

Recently, Momentum has inspected a V90-2MW turbine for one of our existing customers. In this case a leak was observed in the hub. The hub is the assembly point into which the blades are mounted. The hub is mounted on the nacelle, the “house” of the wind turbine. A hydraulic leak in the hub can cause hydraulic oil to penetrate the wing bearings. Over time this will have negative lifetime consequences.

The problem will in general create unnecessary downtime and if replacement of wing bearings is not included in the service contract, it will have a huge economic consequence as well.

Quality Requirements

In Momentum we carry out inspections in multiple situations:

  • In connection with End of Warranty
  • For review purposes, when maintenance services delivered by service providers need to be assessed
  • Before the purchase of wind turbines
  • In the process of changing service agreements

Most of our customers use our quality assurance services to ensure:

  • That the selected service provider lives up to the requirements in the service agreements
  • That the current state of a wind turbine is diagnosed
  • That future possible expenses are foreseen and thoroughly analyzed

Customers, for whom we conduct annual technical inspection of their assets, have during a period of years seen a significant reduction in the number of deviations.

In close Dialogue

In connection with our inspections, Momentum is in close dialogue with service providers regarding observed deviations.

One scenario could be:
Damage to a yaw ringbearing is observed. When receiving signal from the turbine control unit, the yaw ringbearing, and the yaw gear together make the wind turbine turn into the most optimal position according to the given wind direction. Damage is often observed to the gears that intertwine between the components.

In this scenario, our recommendation would be a repair, based on the wind turbine’s lifetime expectancy.

If the wind turbine is to be de-commissioned within a shorter time period, we often recommend the use of recycled spare parts. Momentum has a broad interface with suppliers who sell reused components.

If the wind turbine is expected to be operating for many years to come, we often use new or refurbished components. Our recommendations are always rooted in our customers current and future needs.

We work every day to get the most out of our customers' assets.
We are also ready to help you.


All information on Momentum’s website and any related subsites is provided on an “as is” basis, in good faith and for information purposes only. Momentum makes no representations or warranties (express or implied) and assumes no responsibility or liability in relation to completeness, accuracy, adequacy, reliability of any information on any of Momentum’s websites. Momentum takes no responsibility for external links and content from third parties.