The protection and inspection methods of lotion crane (taking the elevator as an example) should focus on the safety protection device, daily inspection process and test verification. The specific methods are as follows:

1、 Protection methods of safety protection devices

Over roll and over release protection

Function: To prevent lifting containers beyond normal operating range, avoid equipment damage and personnel injury.

Protection method: When the container exceeds the normal terminal stop position by 0.5m, the over roll protection device automatically shuts off and the safety brake brakes; Overplacement protection prevents the container from being lowered beyond the limit.

Key points for inspection: Regularly test the over roll protection device to ensure that the travel switch is connected in series with the safety circuit of the electrical control system. When the switch is triggered, the electromagnet will immediately cut off power.

overspeed protection

Function: Monitor and improve speed to prevent overspeed and loss of control.

Protection method: When the speed exceeds 15% of the maximum value, the device automatically shuts off and brakes.

Key points for inspection: Use simulation tests to lower the speed protection value and observe whether the device is operating; Check if the encoder (installed on the main drum or external gearbox) accurately measures the speed and position.

Overload and undervoltage protection

Function: To deal with power system abnormalities and load anomalies.

Protection method: Automatic power-off when overloaded (current>150% rated value), alarm and disconnect safety circuit when under voltage (voltage<80% rated value).

Key inspection points: Verify the rated current setting to ensure that the overload and undervoltage thresholds meet the standards.

Speed limit protection

Function: For winches with a lifting speed>3m/s, ensure that the terminal speed is ≤ 2m/s.

Protection method: When the speed exceeds the limit, it will automatically cut off power and brake. The device is set to a dual line type to improve reliability.

Key points of inspection: Test the independence of the speed limiting device to ensure that the other line can still function normally when one line fails.

Depth indicator failure protection

Function: To prevent over rolling and over unwinding caused by indicator failure.

Protection method: When the indicator fails, it will automatically power off and brake.

Key inspection points: Verify the principle of the depth indicator over roll switch and ensure that the nut touches the iron to trigger the limit switch.

Barrier gap protection

Function: Real time monitoring of the gap between brake shoes and brake discs to ensure the reliability of the braking system.

Protection method: When the gap between the gates exceeds 2mm, the gap probe will sound an alarm and prompt adjustment.

Inspection points: Regularly check the gap between the gates and adjust it to the specified range.

Sliding rope (loose rope) protection

Function: Monitor the relative movement between the main drum and the steel wire rope to prevent rope breakage accidents.

Protection method: The encoder detects sliding phenomenon, triggers sound and light alarm, locks secondary driving or safety braking.

Key inspection points: Verify the connection between the encoder and the PLC controller to ensure normal data acquisition and processing.

Deceleration function protection

Function: Ensure that the container begins to decelerate in the correct position.

Protection method: When reaching the designed deceleration position, a warning is given and the speed is reduced. The device is set to a double line type.

Key points for inspection: Test the deceleration point setting to ensure that the system can accurately alert and decelerate.

2、 Daily inspection and maintenance methods

Daily inspection content

Mechanical components: Check whether bolts, rivets, pin shafts, etc. are loose, and observe the meshing of the reducer gears.

Hydraulic and braking system: Check the oil supply of the lubrication system and verify the working condition of the braking system (such as hydraulic station pressure and brake clearance).

Protection device: Test the over roll protection device, check the operation of startup, shutdown, and emergency signals.

Connection device: Check if the padding, lifting container, and blocking device are working properly.

Wire rope: Check the arrangement of the wire rope on the drum and whether the rope head is firmly fixed.

Weekly inspection content

Braking system: Focus on inspecting the hydraulic station and brakes to ensure they are in good working condition.

Safety protection device: Check the operation of devices such as over roll, over speed, and speed limit.

Drum and welds: Check if the drum rivets are loose and if the welds are cracked.

Wellhead loading equipment: repair damaged parts to ensure normal operation.

Monthly inspection content

Comprehensive inspection: Conduct a comprehensive inspection of the hoist, including the metal structure, electrical system, etc., to ensure that there is no permanent deformation, visible cracks, or loose nodes.

3、 Experimental verification method

No-load test

Method: Under no-load conditions, perform actions such as rising, falling, shifting, and braking, and repeat the test at various working speeds for no less than 3 times throughout the entire range.

Purpose: To verify the sensitivity and operational reliability of each safety device.

Rated load test

Method: According to the designed load (added at 1/6 of the eccentric position) inside the basket, repeat the no-load test action no less than 3 times.

Purpose: To check the reliability of the action and safety devices under rated load.

Overload test

Method: The test load is 115% of the rated load, and at least 3 times of lifting and lowering are carried out.

Purpose: To verify the stability of the equipment under overload conditions and check that there are no abnormal phenomena in all parts.

The main equipment produced by Hebei Makita: stage electric hoist, electric chian hoist, wire rope electric hoist，Hand chain hoist, lever hoist, pneumatic hoist and other lifting equipment