| 摘要 |
The invention relates to a lifting magnet (11), comprising an emergency power source (121) effective during a mains power failure, said emergency power source having a plurality of high-performance capacitors (12), preferably double-layer capacitors, and to a method for the emergency power supply of a lifting magnet comprising a mains voltage (10), a transmitter (32), a receiver (33) with a relay (311) and an emergency power source (121). According to the invention, the transmitter modulates a (high) frequency test signal (34) on the mains voltage, said test signal being received and evaluated by a receiver connected to the mains voltage, wherein the receiver has a relay, by means of which the emergency power source is connected to the mains voltage when the receiver does not receive the received test signal.
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