Installation example WPM system before stopping position.

Installation example WPM system before stopping position. (Photo: © Kronenberg GmbH)

WPM system for controlling motorized door interlocks


Just in time for the interlift 2022, Kronenberg GmbH is launching the innovative WPM system, an electronic system for controlling motorized door interlocks by wireless power transfer between the car and the pit.

The system can be retrofitted easily without interfering with the control.

Motorized door locks for landing doors have proven themselves for years and offer many advantages. As there are no mechanical actuation devices such as roller levers, rubber rollers, bearing blocks and connecting rods on the door and the retiring cam at the car the installation is much easier. Space in the pit is saved and the installation position of the motorized door interlock can be flexibly chosen. The low noise development and the almost maintenance-free operation are further advantages.

High safety requirements are, however, applied to the control of the motorized door interlocks, as there is a risk of falling into the pit if the control is faulty. It must therefore be ensured that a landing door is only unlocked when the lift car is behind it. Therefore, a safety circuit or a positively driven safety switch is required for each floor. With the new WPM system (Wireless Power Module) by Kronenberg, such complex safety circuits are no longer necessary.

Inductive energy transfer

Both the WPM system and the retiring cam transmit energy in the stopping position area from the car to the pit, in order to unlock the associated landing door by this energy. With the WPM system, the energy is transmitted wireless by an alternating magnetic field from a transmitter on the car to a receiver in the pit. At the retiring cam, on the other hand, there is a kinetic energy transfer from the cam to the mechanical actuating device of the landing door interlock.

Basic principle WPM system in stopping position. Photo: © Kronenberg GmbHBasic principle WPM system in stopping position. Photo: © Kronenberg GmbH

With both systems, energy transfer is only possible in the stopping position area of a floor. All other landing door interlocks are de-energized and remain locked. This ensures that the landing door is only unlocked when the car is behind it.

Both systems require a control signal to lock the door and close the safety circuit before riding. The control signal is required while riding so that the doors remain closed when riding through the floors. In order to enable modernization without intervention in the control, the same control is used as for a retiring cam for the WPM system. A DC or AC voltage between 20 and 250 V can be connected to the input of the WPM system.

Easy installation

The WPM system is installed very easily and quickly using the mounting set included in the scope of delivery, Kronenberg emphasised. Starting in the stopping position of a floor, the transmitter is preferably mounted on the car roof and a receiver is attached to the guide rail in the pit so that the transmitter and receiver face each other at a distance of approx. 10 mm. The receivers on the remaining floors are installed subsequently.

For the electrical installation in the pit, only one two-pole cable is required on each floor between the receiver and the motor electronics of the door interlock. The mains voltage and the control signal are connected to the power supply unit on the car. The connection between the power supply unit and the transmitter is made via the connection cable that is pluggable on both sides.

"Maintenance- and wear-free"

With the innovative WPM system and the DL(F)1MO and CL(F)MO door interlocks, Kronenberg offers a complete solution for the integration of motorized landing door interlocks in existing or new lift installations.

In the case of modernizations, the WPM system in connection with the motorized door interlocks can be integrated without intervention in the control. Existing complex mechanical actuation devices are no longer needed. "As an electronic system with wireless power transfer, it is moreover maintenance- and wear-free and enables permanently reliable operation," Kronenberg explained.

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