Wind turbines present some of the most challenging environments for electrical and electronic installations. Often subject to extremely high humidity levels, high temperatures and vibration, these installations require specialised protection measures above and beyond what would normally be needed under less aggressive conditions.
This was the case recently, when Electrolube was approached by a customer seeking advice on the protection of electrical devices and controls destined for installation within wind turbine units. Although sealed within an enclosure, these devices were nonetheless considered prone to moisture/water ingress as a result of internal condensation. Moreover, due to the levels of mechanical vibration present, the devices also required some form of physical protection.
Electrolube suggested an encapsulation resin as the best solution for protecting these devices from both moisture ingress and vibration damage. Further discussion with the customer revealed that the chosen resin must also be UL approved, offer excellent electrical insulation properties and be able to resist peaks in temperature of up to 120°C. Furthermore, it was deemed essential that the resin was capable of dissipating some of the heat away from the devices.
As a result of these consultations, Electrolube recommended its ER2188 UL94 V-0 approved encapsulation resin for this application.
ER2188 is a flame retardant two-part potting and encapsulating compound with a relative thermal index (RTI) of 130°C, a thermal conductivity of 0.91W/m.K and a high volume resistivity. It provides excellent adhesion to a wide variety of substrates and offers a high level of protection in a range of environments. The flame retardant system also utilises a hardener free of DDM or other aromatic amines.
The customer duly tested the resin for this application and approved it for use.
Ron Jakeman, Group Managing Director of HK Wentworth, Electrolube’s parent company, said, “We are always delighted to be presented with the opportunity to solve problems for our renewable energy customers. It’s what we do best as a solution focused, collaborative and technology driven organisation. We relish the challenge and we’re very pleased with the outcome to provide our wind turbine customer with an effective solution.”
Encapsulation resins offer the highest level of protection for electronic devices, combining good electrical properties with excellent mechanical protection to provide complete insulation for the unit.
It is vital to test a device in a suitable environment, appropriate for its intended end use; this can be in exact conditions or carefully planned accelerated testing. Encapsulation resins can also be tested separately in a number of environments to establish their specifications and suitability for use. These tests typically consist of a cured mass of set dimensions, exposed to controlled atmospheres for a set period of time. The appearance, dimensions and weight of the resin can be measured before and after the test to identify if any changes have occurred. In addition, electrical testing can be performed before and after testing, which again can be generic or specific to the final application.
Epoxy resins have been widely used for many years. They are generally hard, tough and exhibit low shrinkage on cure. Epoxies are characterised by an excellent level of mechanical properties, advanced high temperature performance, good chemical resistance and superior adhesion to a wide variety of substrates.
Electrolube offers a comprehensive range of epoxy, polyurethane and silicone resins for potting, encapsulation and other applications. The great majority of these are two part systems where a resin has to be mixed with a hardener in a defined ratio before use. Two part resin systems are available in bulk or kits, where the resin and hardener are pre-weighed into containers in the correct ratio, avoiding the necessity for weighing by the user.
For further information, please visit www.electrolube.com