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For conveyors with preferred direction of rotation and actuators in process engineering, it must be ensured that the motors always start in the same direction. The correct phase sequence must also be observed for mobile, electrical machines and devices such as used by the fire brigade, the German Federal Agency for Technical Relief or on construction sites. It can happen that the rotating field is not correct and the motor runs backwards.

In various applications, however, it is absolutely necessary that the motor rotates in the correct direction to avoid damage to the plants. The smart motorstarter UG 9256/804 from of the MINISTART series from DOLD with its automatic phase sequence correction ensures that there is always a clockwise rotating field on the motor. A microprocessor analyses the zero crossings of the three phases and detects the phase sequence. Thus a turning in the wrong direction is not possible. In addition, there is an integrated motor protection function and phase failure detection to protect the motor. Due to the small overall width, the space requirement can be reduced by up to 66% compared to the use of conventional devices.

The smart motorstarter is equipped with hybrid relays and thus combines the advantages of robust relay technology with wear-free semiconductor technology. High device availability is ensured by monitoring the semiconductor temperature, ensuring that the semiconductors are voltage-resistant up to 1500 V and that the direction of rotation/relay switching is without load.

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