Eaton is enhancing its PKE electronic motor-protective circuit-breakers with additional convenience functions through the overload relay function of the XZMR module. The PKE-XZMR can be side mounted as an accessory on all PKE motor-protective circuit-breakers and motor starter combinations and is wired with the contactor of the motor to be protected. In the event of an overload, the module receives the corresponding disconnection signal for overload and disconnects the contactor. The PKE motor-protective circuit-breaker remains switched on. This enables the user to clearly distinguish between the two causes of tripping - motor overload (contactor was disconnected) and short-circuit (PKE motor-protective circuit-breaker has disconnected). The two manual and automatic acknowledgement options are provided for resetting the fault. Automatic acknowledgement saves the previous opening of the switch cabinet by qualified personnel in order to switch on the motor-protective circuit-breaker and simplifies plant monitoring, for example in areas that are difficult to access.
Before overload tripping can occur, the device LED on the PKE-XZMR indicates overcurrents in the load circuit. This makes it possible to implement predictive maintenance of the drive and thus reduces possible downtimes. The XZMR module is equipped with an N/C contact for the contactor and an N/O contact for the overload signal. The PKE-XZMR can be used both with the enhanced motor protection blocks (PKE-XTUA...up to 65A) as well as the enhanced system protection blocks (PKE-XTUACP...up to 65A).
The Module provides the PKE motor-protective circuit-breaker with two important convenience functions. The first is the possibility of predictive maintenance with an impending overload. In the event of an overload, the XZMR distinguishes between load currents greater than 100 percent and load currents greater than 105 percent, and indicates both with different flash frequencies via the integrated Status LED. Thanks to this early warning system, users can introduce preventative maintenance measures early in order to avoid any unnecessary downtimes.
The second convenience feature is the automatic restart of the motor after the contactor has tripped in the event of an overload. The type of restart of the XZMR module can be set directly on the device: In Auto mode, the resetting of the contactor after an overload is fully automatic, and is performed manually if the corresponding Manual setting is selected. As the switch position of the PKE remains unchanged in the event of an overload if Auto is set, the motor can restart immediately as soon as the module initiates the corresponding release signal. This saves valuable time and enables the simple autonomous monitoring of plants. If manual operation is selected, the fault signal has to be acknowledged before a restart by pressing the Reset button on the XZMR module. Manual mode is therefore particularly suitable for safety-critical applications.