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GWO Basic Technical Training (BTT) – What You Want to Know

GWO Basic Technical Training (BTT) – What You Want to Know

An Introduction to GWO Basic Technical Training

GWO Basic Technical Training (BTT) is a 4-day long course offered at NRS Training Services. Consisting of three separate modules – mechanical, electrical, and hydraulic – it is designed to give a knowledge foundation to technicians and others working in or near wind turbines. By the end of these three modules, you will be able to solve basic tasks in mechanical, electrical, and hydraulic systems under the supervision of an experienced technician. BTT only needs to be completed once – there is no refresher training, unlike for the Basic Safety Training course.

In this post we’ll explore the content and aims of the three modules, talk about the key learning points that you can expect to cover, and answer the questions we hear most often about this course. Firstly, let’s look at whether this is the right course for you.


BTT Mechanical Module

The mechanical module is an excellent introduction to the basic mechanics of turbine engineering – from the theory of aerodynamics relating to turbine blades to the fitting of bolts using tensioning tools. This is an essential part of training for those unfamiliar with the specifics of wind turbines and their operation.

One of the most useful aspects of the course is learning the principles behind bolting as a means of connecting materials. For the uninitiated, the towers of turbines are generally large, metal tubes built in sections which are bolted together with precision – think giant IKEA furniture and you’re not far off. It’s essential, then, that these bolts are tightened correctly, inspected and maintained – if not, you can now think Jenga.

While talking about the theory of bolting is useful at the start, the real benefit of this module is having the chance to practice the tightening and loosening of bolts in a controlled environment with an experienced instructor behind you. Hydraulic torque tensioning tools can be dangerous and cause injury when used incorrectly – it’s far better to have an experienced instructor mentoring you than cuffing this skill.

As we’ve already seen, precision is vital when building and maintaining turbines. Even small mismeasurements can be a problem, so learning to take accurate readings is a good skill to have. This module sets out how to correctly measure using tools such as micrometres and callipers, as well as how to properly read and care for dial gauges.

Yet perhaps one of the most useful and interesting parts of this module is a broad-brush overview of how a wind turbine works. This is something most of us may have a hazy memory of – sitting in a classroom at 14 years old with an overly-excited physics teacher trying to make you understand principles that not all of us were very interested in.

Two hands holding a micrometre over a brake disc. the NRS Training Services logo is visible on the jumper in the background.
Using a micrometre to accurately measure the width of a particular point on a brake disc.


BTT Electrical Module

An introduction to basic electrical concepts and formulae is always going to be highly relevant in an industry all about electricity generation – but it can take a bright spark to pick it up quickly. Understanding how electricity behaves, the dangers of electricity, and control measures when working with it are key to building and reinforcing a work culture built around electrical safety.

This module begins by taking participants through the basics of electricity – Ohm’s Law, direct and alternating current, and the differences between AC/DC (no, not them…) systems.  These basic principles will give you the foundational knowledge to understand how electricity acts in turbines, and what to be aware of. You will learn the hazards of electricity, particularly high voltage electricity, something which is extremely relevant to anybody working with wind turbines.

After getting to grips with the properties of electricity, you will be familiarised with different electrical components; from basic concepts such as switches and batteries through to generators and processor control systems. This lesson gives you knowledge of the building blocks which make up electrical circuits. The lesson on electrical circuits begins with an in-depth lesson on electrical symbols and the reading of electrical diagrams – something which is useful for any technician. Participants will then build their own electrical circuits using the components they have learned and draw out the plans for these circuits in diagrams using the correct electrical symbols.

As in the mechanical module, an important part of this course is simply giving technicians some knowledge of the inner working of turbines. This is hammered home again in the electrical module when we discuss how the sensors on turbines work. Anyone working on or with turbines should understand the fundamentals of how these sensors work to optimise the energy output of turbines, as well as how electrical energy is generated from the kinetic energy of wind.

Two hands locking a red padlock.
Using the lock-out-tag-out system on the electrical rig to prevent the power being switched on while it’s in use.


BTT Hydraulic Module

Hydraulic systems are simply systems in which a mechanical function operates through liquid pressure. Hydraulics are named for water – hydro in Greek – as the pioneers of this clever system used water as their pressure medium. These systems mostly now use specialised oils – types of hydraulic oil – for the needs of the system. For example, brake fluid is a hydraulic oil which has a high boiling point, so that when it heats it doesn’t evaporate and cause brake failure. While you probably thought about your car when reading that sentence, the same principle applies to the brakes on a wind turbine!

Of the three modules, hydraulics are what participants tend to be least familiar with. The introduction to this module will familiarise you with the concepts of Pascal’s Law, oil and fluid compressibility, and the basic principles and usage of hydraulic systems. At this point, you gain a far more detailed understanding of how mechanical, electrical and hydraulic systems interconnect and allow a wind turbine to work to its full potential.

You will cover in detail what hydraulic pumps do – whether electrical or manual – and how to recognise the symbol in a circuit. You will also cover in the same detail the use of valves, accumulators and sensors in hydraulic systems. Our hydraulic rig allows you to visualise the theory and consolidate your understanding of the principles of hydraulic systems, demonstrating how a hydraulic system operates and incorporating the various components taught in the course.

Anyone who can drive knows the importance of checking a vehicle’s oil. But it’s not just, as many believe, about checking oil quantity – it’s about quality, too. The Oil and Filters lesson gives you experience in handling oil safely, taking and checking samples of oil and checking the oil level. Hydraulic systems can fail as a result of the fluid deteriorating in quality or quantity, so checking these systems is a vital part of turbine maintenance.

BTT - A hand holding a dial gauge towards the camera.
Checking the pressure on a dial gauge, part of the BTT hydraulic module.


Mind the Gap!

Those with experience in the industry may have heard of ‘gap training’. This is a useful and efficient way of marrying up previous training with the GWO standard, allowing individuals who have completed some very select existing wind industry training to bridge the ‘gap’ in training by completing any outstanding lessons rather than completing the whole module or course.

For example, Vestas Service D training package covers almost all of the Mechanical module, and does cover the Electronics and Hydraulics modules – it even covers the mechanical module completely if the participant has three months documented experience in a mechanical environment. If this participant has completed this course and has the relevant experience, they could be awarded the full GWO BTT without taking the course.

Find out more about Gap Training here.


Booking with NRS

You can book directly on our website, or call us on 0208 895 6794. We are available to answer calls 9am-5pm Monday to Friday. If you prefer, or you have any questions, you can email us at We always aim to reply to any queries on the same day, but occasionally there may be some delays in replying.



Do I need to do all of the modules in a single week?

No – you can do them separately. We do offer a package deal for participants to complete all three, however, and would recommend doing this if you can. Doing the courses as a package will also make for a better training experience – the courses link together and make more sense when done together.


What does BTT add to my career?

BTT is an excellent course both for those who have not worked with turbines and those who feel a need to formalise their experience into a qualification. It is not only a solid foundation for the technical side of turbine safety, it also helps people to relate their previous skills into the wind environment. For example, electricians may already know the bulk of the electrical module, but they will learn more about how electrical systems work in turbines and improve their understanding of how their trade works in this very unique environment.


Why train with NRS?

We believe that money shouldn’t be a barrier to a high-quality training experience for people who want to work in renewable energy and power our move to a greener world. For that reason, we strive to keep costs low while ensuring we always exceed or meet the standards set out by GWO. We also provide state-of-the-art equipment to give you a realistic experience which will carry over well into the industry. Our instructors are experienced in technical aspects of the wind industry. We also offer BTT in a 4-day package, useful for those who cannot commit to 5 days.

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