New Contactor / Knife Switch Combination for High-Voltage Switchgear Cabinets
Munich – Schaltbau, located in Munich, has launched a new safety contactor designed for use with control boxes. It combines the functions of the main contactor and the disconnecting and earthing device in a single high-performance unit. A special mechanism provides a positive means of turning the power off by forcing the main contacts open even when they have become welded together.
Thus, with the pantograph still raised to the catenary, the ZH2000 series safety contactor allows for disconnecting individual electrical loads like inverters of motorised trains from the high-voltage power supply which remains available for all other loads in the train. This makes it possible for two maintenance teams to start working in parallel at the high-voltage system of the train and at facilities in the carriages with the hotel power uninterrupted and running. The result is a significant reduction in downtime.
ZH2000 SERIES SAFETY CONTACTOR
The ZH2000 series safety contactor is designed for connection in series with high-voltage inverters of rail vehicles, and as a cut-in unit for the failsafe cut-out of supply voltage.
Mounted in a high-voltage switchgear cabinet, the safety contactor functions like any other main contactor. On opening the door of the switchgear cabinet, a safety loop is being interrupted and the main contactor is switched off electrically. The highest safety for the maintenance teams is guaranteed by the positive opening mechanism of the device, which forces the normally closed safety contacts open even when they have become stuck or welded.
The necessary force for the positive opening operation is supplied by a spring-operating storage. The high-voltage arc that forms between the contacts is quenched by the arc chute of the contactor. After that the disconnecting and earthing operation is carried out and the cabinet door can be padlocked for maintenance in a disconnected position.
KNIFE SWITCH AND HIGH-VOLTAGE CONTACTOR COMBINATION
Combining a knife switch with a high-voltage contactor in one single device has major advantages: for example, a slimmer and more compact design with the main contactor and knife switch sitting next to each other and being functionally united, which results in less sources of error. The disconnecting position remains visible all the time, and expensive redundancies can be avoided.
The input voltage range in accordance with UIC550 is 680V up to 3,000VAC at 16Hz up to 50Hz, and 900V up to 3,000VDC, respectively. The control voltage is 24VDC or 120VDC. The housing of the device is sealed to IP20 and its outward dimensions are 336mm x 418mm x 406mm (width x height x depth).
The ZH2000 is type tested to EN 50155, including for insulation, EMC, vibration and shock. The temperature range is -40°C up to +85°C.