LIFTING MAGNET AND METHOD FOR EMERGENCY POWER SUPPLY
First Claim
9. A method of operating an electromagnetic grab, the method comprising the step of:
- normally powering the grab from a line-voltage power-supply cable;
connecting a transmitter and a receiver having a relay to the cable;
outputting from the transmitter into the line-voltage supply cable a high-frequency test signal;
receiving and evaluating the signal with a receiver connected to the cable and operating the relay to connect an emergency power supply to the cable whenever the receiver is not receiving the test signal.
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Accused Products
Abstract
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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Citations
15 Claims
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9. A method of operating an electromagnetic grab, the method comprising the step of:
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normally powering the grab from a line-voltage power-supply cable; connecting a transmitter and a receiver having a relay to the cable; outputting from the transmitter into the line-voltage supply cable a high-frequency test signal; receiving and evaluating the signal with a receiver connected to the cable and operating the relay to connect an emergency power supply to the cable whenever the receiver is not receiving the test signal. - View Dependent Claims (10, 11)
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12-1. The combination defined in claim 12, further comprising:
means on the grab for charging the emergency power supply when the relay is in the normal position.
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15. The combination defined in claim 15 wherein the limited time period of the receiver is shorter than that of the transmitter.
Specification