On todays “standard” Main and Boom Hoists of STS cranes, numerous problems appear when it comes to emergency-stops or sudden power cut-offs. The rotational kinetic energy (inertia..) of the motors can´t be immediately removed – and this energy generates peak overloads to the gearbox against the closed brakes. Additionally, due to the “traditional” dual brake circuits (high speed service brake and low speed emergency brake), damaged bearings, gears etc. occur due to the resulting tooth flank change of the gearing.