The eccentric locking’s turn

Only half a turn

Siemens’ requirements were not easy to fulfil, because the frequency converter SINAMICS S120 has two connectors, one closely positioned upon the other. Screwing from above would have made it impossible to unlock the lower connector without removing the upper one. This did neither meet the customer’s needs nor Siemens’ requirements. Joachim Masatz, head of the Siemens design office, knows: "Besides a high-quality connector for their connection technology, our customers demand connectors that are easily accessible and un-/lockable - preferably with standard tools."

Accurately fitting these needs, Weidmüller developed the power connector S120 with eccentric locking exclusvely for Siemens. An operator only has to perform half a turn with any screwdriver or hex-wrench – and the connector is locked or unlocked.

Challenge mastered

One great challenge in the development of this solution was the fact that the housings of the frequency converters could not be altered. Up to that moment the housings were prepared for a screwed connection. “To make our solution compatible with the former one, we replaced the thread in the reverse of the device, formerly a screw, with a locating bolt that can be coupled with the connector by half a turn of the eccentric part,” explains Klaus-Dieter Endres who managed the project on the Weidmüller side. Thus the existing housings can effortlessly be prepared for the power connector S120.

The new locking system even solves the problem of the two neighbouring connectors. “As the connector is positioned at the rear side of the SINAMICS S120 frequency converter, the eccentric locking can be operated from the side. This way the lower connector can easily be locked and unlocked whereas the upper connector remains mounted”, says Key Account Manager Peter Schuster.

“We had highest demands on performance and user-friendliness concerning this solution,” Masatz says. “In Weidmüller we found a competent partner who could cope with our requirements providing the necessary competence in technology.”