Secondary emergency protection device based on electromagnetic crane

Abstract

The invention provides a secondary emergency protection device based on an electromagnetic crane. Comprising a device body, and a multifunctional display screen, a switch and an audible and visual alarm are arranged on the front face of the device body; a power switch, an electromagnetic hoist input interface, a charging interface and an electromagnetic hoist output quick plug are arranged on the side surface; an internal circuit is arranged in the device body and comprises a reel power supply, a direct-current power supply, a rectifier bridge, a first fuse, a battery pack, a second fuse, a first direct-current power supply DC, a second direct-current power supply DC, a voltmeter, a first solid-state relay, a diverter, a PLC, a quick-plug positive electrode, a quick-plug negative electrode, a key switch, an acousto-optic buzzer, an electric quantity display and a second solid-state relay. When a magnetic head of the electromagnetic hoist is powered off due to other fault reasons, the PLC detects the power failure and can intervene instantly, it is guaranteed that the electromagnetic hoist does not lose magnetism and a hoisted object does not fall off, the audible and visual alarm warns constructors at the first time, and the constructors have 10 minutes to place the hoisted object in a safe area.

Description

Technical Field

[0001] The invention relates to emergency protection in the field of electromagnetic cranes, and in particular to a secondary emergency protection device based on electromagnetic cranes. Background Art

[0002] At present, the electromagnetic crane in use is equipped with an electromagnetic power-off protection system. However, when the line from the electromagnetic holding control box to the front end of the electromagnet is short-circuited or broken, the electromagnetic head will lose its magnetic force, causing the hoisted object to fall from a high altitude, which may cause damage to the hoisted object, damage to equipment and facilities, and casualties among other consequences. In order to avoid similar safety accidents, the present patent is specially developed. Summary of the invention

[0003] In order to solve the deficiencies in the prior art, the electromagnetic system fails and the electromagnetic force disappears when the electromagnetic crane circuit is short-circuited or broken during use, and the hoisted object is prone to falling and causing safety accidents, the embodiment of the present application provides a secondary emergency protection device based on the electromagnetic crane. The emergency protection device automatically intervenes through the PLC in the event of an accident to ensure that the electromagnetic crane does not lose its magnetism and the hoisted object does not fall. At the same time, the sound and light alarm warns the construction personnel in the first time, and the battery storage allows the construction personnel to have 10 minutes to place the hoisted object in a safe area, avoiding the occurrence of safety accidents after power failure, and solving the technical problems of potential safety accidents of the electromagnetic crane.

[0004] The solution adopted by the embodiment of the present application to solve the technical problem is: A secondary emergency protection device based on an electromagnetic crane comprises a device body, a multifunctional display screen is arranged on the front of the device body, a switch is arranged on one side of the multifunctional display screen, and an audible and visual alarm is arranged on the other side, forming a status display function and an alarm function of the device; A power switch is provided on the upper side of the device body, and an electromagnetic crane input interface and a charging interface are arranged in sequence below the power switch. An electromagnetic crane output quick plug is provided on the lower side of the device body to ensure the maintenance and operation of the device; An internal circuit is arranged inside the device body, and the internal circuit includes a reel call, a DC power supply, a rectifier bridge, a first fuse, a battery pack, a second fuse, a first DC power supply DC, a second DC power supply DC, a voltmeter, a first solid-state relay, a shunt, a PLC, a quick-insert positive and negative pole, a key switch, an audible and visual buzzer, a power display and a second solid-state relay, which together complete the processing function of the internal circuit; Among them, the voltmeter and the battery pack provide information on the multi-function display screen; the shunt, the first fuse, the second fuse, the first DC power supply DC and the second DC power supply DC are used to detect faults in time, and the first solid-state relay, the second solid-state relay and the sound and light buzzer maintain the power supply and alarm function of the device; when the magnetic head of the electromagnetic crane loses power due to other faults, it is detected by the PLC and can intervene instantly to supply power to the electromagnetic crane to maintain the proper magnetic force, and at the same time issue a fault prompt through the sound and light alarm.

[0005] In a preferred embodiment, the power supply magnetization time of the device is 10 minutes.

[0006] In a preferred embodiment, in the internal circuit, when the main switch is closed, the electromagnetic crane in the cab starts the hoisting operation. After power is turned on, the DC power from the crane power drum is fed into the fixed positive and negative poles of the output through the rectifier bridge: All the way through the first solid-state relay, the shunt and the positive pole of the quick-plug positive and negative poles to the electromagnetic coil of the electromagnet, and output from the other end of the electromagnetic coil to the negative pole to form a loop; The other way is through the first fuse to the DC power supply DC output 24V and is transmitted to the PLC power supply through the key switch; At the same time, the third battery pack as a backup power source outputs 24V emergency power to the DC power supply through the second fuse to supply power to the PLC; When the PLC detects that the crane power line is short-circuited or open-circuited, the PLC detection signal is immediately activated, switching to the backup power battery pack to work, and the second solid-state relay continues to input current to the magnetic head of the electromagnetic crane. At the same time, the sound and light buzzer receives a fault signal from the PLC. At this time, the sound and light alarm emits sound and light to remind the operator to take emergency measures.

[0007] In a preferred embodiment, the battery pack is a lithium battery.

[0008] In a preferred embodiment, the electromagnetic crane input interface and the electromagnetic crane output quick plug have the advantage of not distinguishing between positive and negative poles. After the positive and negative DC power from the crane power supply is integrated through a rectifier bridge, it is directly connected to the electromagnetic crane input interface and the electromagnetic crane output quick plug to achieve the anti-reverse connection protection of the device.

[0009] In order to further solve the technical problem to be solved by the embodiment of the present application, the embodiment of the present application provides a method for applying a secondary emergency protection device based on an electromagnetic crane, comprising the following steps: Step 1: First, insert the electromagnetic plug of the electromagnetic crane into the electromagnetic crane input interface and the electromagnetic crane output quick plug of the device at the same time, and then turn on the power switch; Step 2: Insert the key into the switch, and the multi-function display will display the current status of the electromagnetic crane, including the open or short circuit status of the electromagnetic coil, the power of the device through the power display, and the voltmeter will display the current voltage; Step 3: When construction begins, the construction personnel start the electromagnetic crane to start the hoisting operation. The DC power supply from the drum is sent to the fixed positive and negative poles through the rectifier bridge output: All the way through the first solid-state relay, the shunt, the positive pole of the quick-plug positive and negative poles to the electromagnetic coil of the electromagnet, and output from the other end of the electromagnetic coil to the negative pole to form a loop; Another way is through the first fuse to the DC power supply DC output 24V and then transmitted to the PLC through the key switch. At this time, the PLC detects the overload, undervoltage, open circuit or short circuit status of the electromagnetic crane before working, and the battery pack power provided by the power display; At the same time, the third battery pack as a backup power source outputs 24V emergency power to the DC power supply through the second fuse to supply power to the PLC; When the PLC detects that the crane power line is short-circuited or open-circuited, the PLC detection signal is immediately started, and the battery pack of the backup power supply is switched to work. The second solid-state relay continues to input current to the electromagnetic crane magnetic head to prevent the electromagnetic crane from stopping working. The PLC outputs an audible and visual buzzer to alarm and prompt that a fault has occurred. The audible and visual alarm 7 emits sound and light to remind the operator to make emergency treatment. At this time, the operator gets the information and makes an emergency response, and puts the hoisted object in a safe area to avoid safety accidents in the hoisting operation. Step 4: After the lifting operation is completed, check the information displayed on the multi-function display. If the power display shows that the power is too low, connect the charging port to charge. If the power display shows that the power is sufficient, turn off the power switch and pull out the key to turn off the switch; Step 5: Unplug the electromagnetic plug of the electromagnetic crane from the electromagnetic crane input interface and the electromagnetic crane output quick plug, and keep the device properly.

[0010] Positive effects: 1. Since the embodiment of the present application adopts a technical means that when the PLC detects that the crane power supply circuit is short-circuited or open-circuited, the PLC detection signal is immediately started, switching to the backup power supply, and the second solid-state relay continues to input current to the magnetic head to prevent the electromagnetic crane from stopping working. At the same time, the PLC outputs an audible and visual buzzer to alarm and prompt the occurrence of a fault. It effectively solves the technical problem in the prior art that when the electromagnetic crane circuit is short-circuited or open-circuited, the electromagnetic force disappears, causing the hoisted object to fall, thereby achieving the technical effect of avoiding safety hazards.

[0011] 2. Since the embodiment of the present application adopts the technical means of using lithium batteries as the battery pack, it effectively solves the technical problem in the prior art that when the electromagnetic hoist line is short-circuited or open-circuited, the electromagnetic force disappears, causing the hoisted object to fall. The device is light as a whole, charges quickly and efficiently, has a large battery capacity, and can be disassembled and installed at any time as needed, thereby achieving a technical effect of adapting to different work scenarios.

[0012] 3. Since the embodiment of the present application adopts the technical means of using PLC to detect overload, undervoltage, open circuit or short circuit status of the electromagnet coil, and at the same time controlling the high-speed second solid-state relay to perform conversion, it effectively solves the technical problem in the prior art that when the electromagnetic hoist line is short-circuited or broken, the electromagnetic force disappears, causing the hoisted object to fall, thereby achieving the technical effect that the emergency power supply can be instantly intervened when an alarm occurs.

[0013] 4. Since the embodiment of the present application adopts the technical means of setting an electromagnetic hoist input interface and an electromagnetic hoist output quick-plug on the side of the device body, the positive and negative DC power supplies from the crane power supply are integrated through a rectifier bridge. The input power supply of the device has anti-reverse connection protection and has the advantage of not distinguishing between positive and negative poles. It effectively solves the technical problem in the prior art that when the electromagnetic hoist line is short-circuited or open-circuited, the electromagnetic force disappears, causing the hoisted object to fall, thereby achieving a technical effect of simple operation and wide application.

[0014] A secondary emergency protection device based on an electromagnetic crane is suitable for application. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 This is the front view of the structure of this embodiment; Figure 2 It is a side view of the structure of this embodiment; Figure 3 This is the electrical principle block diagram of this embodiment; Figure 4 This is the PLC control principle block diagram of this embodiment.

[0017] In the figure, 1. power switch, 2. charging interface, 3. electromagnetic crane input interface, 4. electromagnetic crane output quick plug, 5. switch, 6. multi-function display screen, 7. sound and light alarm, 8. reel incoming call, 9. DC power supply, 10. rectifier bridge, 11. first insurance, 12. battery pack, 13. second insurance, 14. first DC power supply DC, 15. second DC power supply DC, 16. voltmeter; 17. first solid-state relay; 18. shunt, 19. PLC, 20. quick plug positive and negative poles, 21. key switch, 22. sound and light buzzer, 23. power display, 24. second solid-state relay. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Although the embodiments of the present invention have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the attached claims and their equivalents. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0019] As shown in the figure, a secondary emergency protection device based on electromagnetic suspension includes a device body, a multifunctional display screen 6 is arranged on the front of the device body, a switch 5 is arranged on one side of the multifunctional display screen 6, and an audible and visual alarm 7 is arranged on the other side, forming the status display function and alarm function of the device; A power switch 1 is provided on the upper side of the device body, an electromagnetic crane input interface 3 and a charging interface 2 are arranged in sequence below the power switch 1, and an electromagnetic crane output quick plug 4 is provided on the lower side of the device body to ensure the maintenance and operation of the device; An internal circuit is arranged inside the device body, and the internal circuit includes a reel call 8, a DC power supply 9, a rectifier bridge 10, a first fuse 11, a battery pack 12, a second fuse 13, a first DC power supply DC14, a second DC power supply DC15, a voltmeter 16, a first solid-state relay 17, a shunt 18, a PLC 19, a quick-insert positive and negative pole 20, a key switch 21, an audible and visual buzzer 22, a power display 23 and a second solid-state relay 24, which together complete the processing function of the internal circuit; Among them, the voltmeter 16 and the battery pack 12 provide multi-function display screen information; the shunt 18, the first fuse 11, the second fuse 13, the first DC power supply DC14 and the second DC power supply DC15 are used to detect faults in time, and the first solid-state relay 17, the second solid-state relay 24 and the sound and light buzzer 22 maintain the power supply and alarm function of the device; when the magnetic head of the electromagnetic crane is powered off due to other faults, the device can detect it through PLC19 and intervene instantly to supply power to the electromagnetic crane to maintain the proper magnetic force to prevent the hoisted object from falling off, and at the same time issue a fault prompt through the sound and light alarm 7.

[0020] The power supply and magnetization time of the device is 10 minutes. During this time, the hoisted objects can be placed stably in a safe area to prevent safety accidents.

[0021] In the internal circuit, when the main switch is closed, the electromagnetic crane in the cab starts the hoisting operation. After power is turned on, the DC power supply 9 of the crane power drum 8 is output through the rectifier bridge 10 and the fixed positive and negative poles are respectively sent to: All the way through the first solid-state relay 17, the shunt 18 and the positive pole of the quick-plug positive and negative poles 20 to the electromagnetic coil of the electromagnet, and output from the other end of the electromagnetic coil to the negative pole to form a loop; Another way is through the first fuse 11 to the DC power supply DC14 to output 24V and then to the PLC19 through the key switch 21. At this time, the PLC19 can detect the overload, undervoltage, open circuit or short circuit state of the electromagnetic crane before working, and the power of the battery pack 12 provided by the power display 23; At the same time, the third battery pack 12 as a backup power source outputs an emergency power supply 24V to the DC power supply DC15 through the second fuse 13 and transmits it to the PLC19 for power supply. At this time, the electromagnetic crane performs normal hoisting operations; When PLC19 detects that the crane power line is short-circuited or open-circuited, the PLC19 detection signal is immediately started, and the battery pack 12 of the backup power supply is switched to work. The second solid-state relay 24 continues to input current to the magnetic head of the electromagnetic crane to prevent the electromagnetic crane from stopping working. At the same time, the sound and light buzzer 22 receives a fault signal from PLC19. At this time, the sound and light alarm 7 emits sound and light to remind the operator to take emergency measures.

[0022] The battery pack 12 is a lithium battery.

[0023] The electromagnetic crane input interface 3 and the electromagnetic crane output quick plug 4 have the advantage of not distinguishing between positive and negative poles. After the positive and negative DC power supplies 9 from the crane power supply are integrated through the rectifier bridge 10, they are directly connected to the electromagnetic crane input interface 3 and the electromagnetic crane output quick plug 4 to achieve the anti-reverse connection protection of the device.

[0024] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages: When PLC19 detects that the crane power line is short-circuited or open-circuited, the PLC19 detection signal is immediately started and switched to the backup power supply. The second solid-state relay 24 continues to input current to the electromagnetic crane head to prevent the electromagnetic crane from stopping working. At the same time, PLC19 outputs the sound and light buzzer 22 to alarm and prompt the failure. Therefore, the device can avoid the occurrence of safety hazards and ensure the safety of plates, equipment, facilities and personnel.

[0025] Since the battery pack 12 is a lithium battery, the device is lightweight as a whole, charges quickly and efficiently, has a large battery capacity, and can be disassembled and installed at any time as needed to adapt to different working scenarios.

[0026] Since the device utilizes PLC 19 to detect overload, undervoltage, open circuit or short circuit of the electromagnet coil, and controls the high-speed second solid-state relay 24 to switch, the emergency power supply can be instantly involved when an alarm occurs.

[0027] Since the electromagnetic crane input interface 3 and the electromagnetic crane output quick plug 4 are arranged on the side of the device body, the positive and negative DC power supplies 9 from the crane power supply are integrated through the rectifier bridge 10. Therefore, the input power supply of the device has anti-reverse connection protection, has the advantage of not distinguishing between positive and negative poles, is easier to operate, and is more widely used.

[0028] The working process of this embodiment: A method for applying a secondary emergency protection device based on an electromagnetic crane includes the following steps: Step 1: First, insert the electromagnetic plug of the electromagnetic crane into the electromagnetic crane input interface 3 and the electromagnetic crane output quick plug 4 of the device at the same time, and then turn on the power switch 1; Step 2: insert the key into the switch 5, and display the current state information of the electromagnetic crane through the multi-function display 6, including the open circuit or short circuit state of the electromagnetic coil, check the power of the device through the power display 23, and the voltmeter 16 displays the current voltage; Step 3: When construction begins, construction workers start the electromagnetic crane to start hoisting operations. The DC power supply 9 from the drum 8 outputs fixed positive and negative electrodes through the rectifier bridge 10 and is respectively sent in: one way passes through the first solid-state relay 17, the shunt 18, and the positive electrode of the quick-plug positive and negative electrodes 20 to the electromagnetic coil of the electromagnet, and is output from the other end of the electromagnetic coil to the negative electrode to form a loop; the other way passes through the first insurance 11 to the DC power supply DC14 to output 24V, which is transmitted to the PLC19 through the key switch 21 for power supply. At this time, the PLC19 detects the overload, undervoltage, open circuit or short circuit status of the electromagnetic coil before the electromagnetic crane works, and the power of the battery pack 12 provided by the power display 23; at the same time, the third step The battery pack 12 serving as a backup power source outputs an emergency power supply 24V through the second fuse 13 to the DC power supply DC15 to supply power to the PLC19; when the PLC19 detects that the crane power supply line is short-circuited or disconnected, the PLC19 detection signal is immediately started, and the battery pack 12 serving as the backup power source is switched to work, and the current continues to be input to the magnetic head of the electromagnetic crane through the second solid-state relay 24 to prevent the electromagnetic crane from stopping working, and the PLC19 outputs an audible and visual buzzer 22 to alarm that a fault has occurred, and the audible and visual alarm 7 emits audible and visual signals to remind the operator to take emergency measures. At this time, the operator receives the information and makes an emergency response, and places the hoisted object in a safe area to avoid safety accidents during the hoisting operation. Step 4: After the lifting operation is completed, check the information displayed on the multi-function display screen 6. If the power display 23 shows that the power is too low, connect the charging interface 2 for charging. If the power display 23 shows that the power is sufficient, turn off the power switch 1 and remove the key to turn off the switch 5. Step 5: Pull out the electromagnetic plug of the electromagnetic crane itself on the electromagnetic crane input interface 3 and the electromagnetic crane output quick plug 4, and keep the device properly.

[0029] In summary, the device not only has emergency protection measures during the construction process, but also can detect the status information of the electromagnetic crane before construction. Therefore, the device can play a role in avoiding the safety risks in the field of electromagnetic cranes. The circuit principle and design concept of the device also have certain reference value for other fields.

[0030] It is worth noting that the contents not described in detail in the specification belong to the prior art known to those skilled in the art, and the model parameters of the sound and light alarm 7, voltmeter 16 and PLC19 are not specifically limited and can be determined using conventional equipment. In this technical solution, the electrical control components not mentioned are not shown in the figure because they belong to the prior art and will not be described here.

[0031] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A secondary emergency protection device based on electromagnetic suspension, characterized by: The device comprises a device body, a multifunctional display screen (6) is arranged on the front of the device body, a switch (5) is arranged on one side of the multifunctional display screen (6), and an audible and visual alarm (7) is arranged on the other side, so as to form a status display function and an alarm function of the device; A power switch (1) is provided on the upper side of the device body, an electromagnetic crane input interface (3) and a charging interface (2) are arranged in sequence below the power switch (1), and an electromagnetic crane output quick plug (4) is provided on the lower side of the device body to ensure maintenance and operation of the device; An internal circuit is arranged inside the device body, and the internal circuit includes a reel call (8), a DC power supply (9), a rectifier bridge (10), a first fuse (11), a battery pack (12), a second fuse (13), a first DC power supply (14), a second DC power supply (15), a voltmeter (16), a first solid-state relay (17), a shunt (18), a PLC (19), a quick-insert positive and negative poles (20), a key switch (21), an audible and visual buzzer (22), a power display (23) and a second solid-state relay (24), which together complete the processing function of the internal circuit; The voltmeter (16) and the battery pack (12) provide information on the multifunctional display screen; the shunt (18), the first fuse (11), the second fuse (13), the first direct current power supply DC (14) and the second direct current power supply DC (15) are used to detect faults in a timely manner; the first solid-state relay (17), the second solid-state relay (24) and the sound and light buzzer (22) maintain the power supply and alarm function of the device; when the magnetic head of the electromagnetic crane is powered off due to other faults, the PLC (19) detects it and intervenes instantly to supply power to the electromagnetic crane to maintain the proper magnetic force, and at the same time issues a fault prompt through the sound and light alarm 7.

2. According to claim 1, a secondary emergency protection device based on electromagnetic suspension is characterized in that: The power supply magnetization time of the device is 10 minutes.

3. According to claim 1, the secondary emergency protection device based on electromagnetic suspension is characterized in that: In the internal circuit, when the main switch is closed, the electromagnetic crane in the cab starts the hoisting operation. After power is turned on, the DC power supply (9) of the crane power drum (8) is output through the rectifier bridge (10) and the fixed positive and negative poles are respectively sent to: Passing through the first solid-state relay (17), the shunt (18) and the positive pole of the quick-plug positive and negative poles (20) to the electromagnetic coil of the electromagnet, the output is output from the other end of the electromagnetic coil to the negative pole to form a loop; Another path passes through the first fuse (11) to the DC power supply DC14 to output 24V, which is then transmitted to the PLC (19) through the key switch (21) for power supply; At the same time, the third battery pack (12) serving as a backup power source outputs an emergency power supply 24V to the DC power source DC15 through the second fuse (13) and transmits it to the PLC (19) for power supply; When the PLC (19) detects that the crane power line is short-circuited or open-circuited, the PLC (19) detection signal is immediately activated, and the battery pack (12) of the backup power supply is switched to work, and the second solid-state relay (24) continues to input current to the magnetic head of the electromagnetic crane. At the same time, the sound and light buzzer (22) receives the fault signal from the PLC (19), and the sound and light alarm (7) emits sound and light to remind the operator to take emergency measures.

4. According to claim 1, the secondary emergency protection device based on electromagnetic suspension is characterized in that: The battery pack (12) is a lithium battery.

5. According to claim 1, the secondary emergency protection device based on electromagnetic suspension is characterized in that: The electromagnetic crane input interface (3) and the electromagnetic crane output quick plug (4) have the advantage of not distinguishing between positive and negative poles. After the positive and negative poles of the DC power supply (9) from the crane power supply are integrated through a rectifier bridge (10), they are directly connected to the electromagnetic crane input interface (3) and the electromagnetic crane output quick plug (4) to achieve reverse connection protection of the device.

6. A method for applying a secondary emergency protection device based on an electromagnetic crane, characterized in that: The following steps are involved: Step 1: First, insert the electromagnetic plug of the electromagnetic crane into the electromagnetic crane input interface (3) and the electromagnetic crane output quick plug (4) of the device at the same time, and then turn on the power switch (1); Step 2: Insert the key into the switch (5), and display the current status information of the electromagnetic crane through the multi-function display (6), including the open circuit or short circuit status of the electromagnetic coil, check the power of the device through the power display (23), and the voltmeter (16) displays the current voltage; Step 3: When construction begins, the construction personnel start the electromagnetic crane to start the lifting operation. The DC power supply (9) from the drum (8) is sent to the fixed positive and negative poles through the rectifier bridge (10): It passes through the first solid-state relay (17), the shunt (18), the positive pole of the quick-plug positive and negative poles (20) to the electromagnetic coil of the electromagnet, and is output from the other end of the electromagnetic coil to the negative pole to form a loop; Another path passes through the first fuse (11) to the DC power supply DC14 to output 24V, which is then transmitted to the PLC (19) through the key switch (21) for power supply. At this time, the PLC (19) detects the overload, undervoltage, open circuit or short circuit state of the electromagnetic coil before the electromagnetic crane works, and the power level of the battery pack (12) provided by the power display (23); At the same time, the third battery pack (12) serving as a backup power source outputs an emergency power supply 24V to the DC power source DC15 through the second fuse (13) and transmits it to the PLC (19) for power supply; When the PLC (19) detects that the power line of the crane is short-circuited or disconnected, the PLC (19) immediately starts detecting a signal, switches to the backup power supply battery pack (12) to operate, continues to input current to the magnetic head of the electromagnetic crane through the second solid-state relay (24), prevents the electromagnetic crane from stopping working, and the PLC (19) outputs an audible and visual buzzer (22) to alarm and prompt that a fault has occurred, and the audible and visual alarm (7) emits sound and light to remind the operator to take emergency measures. At this time, the operator receives the information and takes emergency response, and moves the hoisted object to a safe area, thereby avoiding safety accidents during the hoisting operation. Step 4: After the lifting operation is completed, check the information displayed on the multi-function display screen (6). If the power display (23) shows that the power is too low, connect the charging interface (2) to charge. If the power display (23) shows that the power is sufficient, turn off the power switch (1) and remove the key to turn off the switch (5). Step 5: Pull out the electromagnetic plug of the electromagnetic crane from the electromagnetic crane input interface (3) and the electromagnetic crane output quick plug (4), and keep the device in a safe place.

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