Menzel Elektromotoren designed and manufactured three powerful 6600 V squirrel-cage motors as integral components for pit fans.
The customer specified a motor housing as compact as possible in cylindrical design. The greatest challenge was to implement the required rated power of 1700 kW in a cylindrical housing. Menzel therefore designed rib-cooled motors (cooling type IC 411) in size 630, an extremely unusual design for this size. The manufacturing process is complex, but the result is optimal for the cramped installation conditions.
To save additional space, all connection cables are also routed out of the motors and the terminal boxes are mounted outside the fans. Since the driven fan wheels are each seated directly on the motor shaft, the motor bearings must also support radial loads of up to 20700 N as well as axial loads of up to 27000 N. To meet the required bearing life of 100,000 h, Menzel manufactured the motors with a special rolling bearing setup.
The motors also have a second shaft end where a holding brake is mounted by the customer. The three-phase squirrel-cage motors are designed for operation on a frequency converter (S9 operating mode) with speed changes and reversal of the direction of rotation. This enables the mine ventilation fans not only to ventilate the mine, but also to extract hazardous mine gases if required.