Blade Pitch Brake

ERS Series and 1EB Series are electrically-released, spring-set brakes that offer a high-performance, cost-effective solution for applications that require both “static” holding power and the ability to withstand high inertia dynamic stops in an emergency situation.

Warner Electric has modified its ERS Series brakes to serve as pitch brakes for wind turbine applications. Each of the three blades on a typical turbine can be individually positioned (rotated) to achieve maximum efficiency while operating in changing wind conditions.

The electromagnetic brake is mounted outboard of an inductive encoder which is mounted to the back of a motor to position the blades to the proper pitch. In normal use, the brake functions as a static brake to hold the blades from rotating in a power-off situation, during routine maintenance or for other reasons.

However, the design spec for one major manufacturer requires the brake to also be able to make 1,000 fully loaded dynamic stops during its service life. The largest in the Warner Electric ERS Series, the 11.3-pound ERS68, has been tested to a capacity of more than 20,000 fully-loaded dynamic stops, surpassing the design spec by a factor of 20. The ERS68 brake offers 100 ft. lbs. of static torque with a maximum of 2,000 RPM and a brake release time of 0.2 sec.

ERS68 blade pitch brakes also offer the advantage of being a one-piece design, fully-enclosed and painted to withstand extreme environmental conditions (salt-spray, condensation, water, etc.).