E-RAD: a better way to tighten and check many bolts
February 2014 – Windpower Engineering & Development
It’s necessary to re-torque a wind turbine’s bolts at OEM prescribed intervals because bolts occasionally work themselves loose. Several hundred of them may need checking on a typical utility-scale turbine. Recent electric wrenches provide a more efficient tool for that task. One version from our company comes with several advantages over other torquing techniques.
The E-RAD series of wrenches provides a fast, reliable, and safe way for installing and removing heavy duty fasteners. The company adds that the tools are lighter, faster, stronger, and more accurate than conventional bolting tools. For instance, compared to hydraulic wrenches, the electric tool significantly decreases tightening times through the delivery of smooth and continuous torque. The relatively low weight of the tool comes in part from its patented planetary gearbox combined with an ergonomic design. The two features provide the highest power-to-weight ratio, controlled bolting system on the market.
Tests show that the servo control shuts off at required torque with an accuracy of ±3% and a repeatability of ±2%. Conventional methods often determine bolt torque by monitoring a pressure gauge, which makes accuracy unreliable.