Groschopp has realized a drive unit of commutator motor and worm gear for the spring tension in medium voltage switches. The integrated solution saves space, components, processing steps and assembly time. After the functions of engine and transmission and their interaction have been proven for years, the integration into a common housing should contribute above all to the cost reduction. By using a built-in motor without housing a very compact solution could be realized.
With the integration of the gearbox into the AS end shield, mechanical parts and processing steps are eliminated, which also saves money. The drive unit in this form is available in a size with four different windings, with which eight voltage levels from 24 V DC to 250 V AC / DC can be realized. In order to optimally adapt the drive parameters to the application, they were determined using a medium-voltage switch provided. Only an optimization of the individual efficiencies of engine and gearbox enabled a good efficiency of the integrated drive unit. The compact design achieved in this way also meets ecological demands through material savings. The characteristics of the motor fit exactly to the required spring tension values of the switch. The drive is for a power output of 140 W at 330 min-1designed.
The integrated worm gear in the plastic housing saves costs for material and assembly. Unlike other designs, the ball bearings are already integrated in injection molding in this solution. This eliminates an additional end shield. The separate assembly of the bearing is eliminated because they are molded and so further processing steps are dispensable. The gear cover is still made of zinc die-cast. Although the drive unit is attached only at two points, the necessary stability is maintained. The cutting of the two threads is the only mechanical machining in the housing cover. Also, the bearing of the motor shaft is now part of the transmission.
Commutator motors can be operated with both direct current and alternating current. The carbon brush holder ensures reliable, trouble-free operation. Wear parts such as the carbon brushes are adapted to the life of the switch with guaranteed 10.000 circuits, so that a service for the replacement of motor or carbon brushes is usually not required. The insensitivity to interference, which results from the uncomplicated mechanical structure without electronics, particularly appeals to companies that, for example, supply energy suppliers with switches and similar components.