Protective measures and inspection methods in the use of electric winches

1、 Eight core protection measures

The safe operation of electric winches relies on the following key protection systems, and their sensitivity needs to be regularly verified:

Anti roll protection

Function: To prevent excessive winding of steel wire rope from causing equipment to lose control.

Inspection method: Manually trigger the over roll valve, observe whether the clutch is released and whether the disc brake is immediately applied. After resetting, run at low speed to the set height to verify the alarm and power-off functions.

Overspeed Protection

Function: To prevent the winch from losing control during high-speed operation.

Inspection method: Monitor the operating speed through a frequency converter or speed measuring device to ensure that it does not exceed 10% of the rated value.

Overload and undervoltage protection

Function: To prevent motor damage due to overload or insufficient voltage.

Inspection method:

Overload: Use a force measuring device to gradually load up to 110% of the rated load and verify the automatic shutdown function.

Undervoltage: Simulate voltage fluctuations (± 5% rated value) and check if the motor stops or slows down.

speed limit protection

Function: Control the lifting speed to avoid heavy objects swinging or mechanical impact caused by excessive speed.

Inspection method: Measure the speed of the steel wire rope with a speed measuring device to ensure compliance with standards (such as 30-130m/min for fast type and 7-13m/min for slow type).

Broken shaft protection

Function: Prevent shaft breakage from causing heavy objects to fall.

Inspection method: Regularly check the temperature rise of the shaft end bearing (≤ 40 ℃), the temperature of the oil pool (≤ 80 ℃), and whether there is oil leakage at the shaft end.

Barrier gap protection

Function: Ensure that the clearance between the brake shoe and the brake wheel is within a safe range (usually ≤ 1.5mm).

Inspection method: Measure the brake clearance with a feeler gauge, adjust it to the specified value, and test the brake response time (≤ 0.2 seconds).

Loose rope protection

Function: To prevent the steel wire rope from becoming loose and causing entanglement, confusion, or loss of groove.

Inspection method: Simulate the slack state of the steel wire rope, verify whether the protective device can automatically stop and alarm.

Deceleration function protection

Function: To prevent motor overheating or transmission system overload.

Inspection method: Monitor the motor current and temperature during the deceleration phase to ensure that they do not exceed the rated values.

2、 Systematic inspection method

The inspection of electric winches should cover the three core systems of mechanical, electrical, and safety devices. The specific process is as follows:

Mechanical structure inspection

Connectors: Check whether the bolts in the base, bearing seat, drum and other parts are loose (torque compliance rate ≥ 95%).

Transmission components:

Gear meshing condition: tooth wear ≤ 20%, no cracks or broken teeth.

Lubrication status: The oil level in the oil tank is within the scale range, and the oil has not deteriorated (acid value ≤ 2mgKOH/g).

a wire rope:

Diameter deviation: Deviation from nominal diameter is ≤± 3%.

Number of broken wires: not exceeding 10% of the total number of wires (such as 6 × 19+1 steel wire rope, with no more than 3 broken wires per strand).

Neat arrangement: There is no climbing or disorderly rope phenomenon, and the rope head is firmly fixed (rope clamping device or special rope container).

Electrical system inspection

Power supply and wiring:

Voltage stability: fluctuation range within ± 5% (for example, in a 380V system, 361-399V is allowed).

Insulation resistance: ≥ 1M Ω (measured with a 500V megohmmeter).

Control device:

Operation handle, switch, emergency stop button: The function is sensitive and there is no jamming.

Signal device: The sound and light signals are clear and identifiable at a distance of ≥ 50m.

Motor and brake:

Motor temperature rise: ≤ 60 ℃ (detected with an infrared thermometer).

Brake clearance: The clearance between the brake shoe and the brake wheel is ≤ 1.5mm, and the braking response time is ≤ 0.2 seconds.

Safety device inspection

Limit protection:

Upper and lower limit switches: reliable action, can immediately stop the machine after triggering.

Protective device:

Exposed rotating parts (such as drums and brakes): Install protective covers to prevent personnel from coming into contact.

Edge height of the drum: ≥ 2.5 times the diameter of the steel wire rope (e.g. 20mm diameter steel wire rope, edge height ≥ 50mm).

Emergency shutdown:

Main stop switch: set near the operating position, it can quickly cut off the main power supply in emergency situations.

Run test

No load trial operation:

Run forward and reverse for 30 minutes each, check the stability of the operation (no abnormal noise or vibration).

Sealing: There is no leakage at any connection point (such as oil tank, hydraulic station).

Load testing:

Load gradually to the rated load (25%, 50%, 75%, 100%), with a lifting height of ≥ 5m each time and a minimum of 10 times.

Measure the maximum tensile force (accuracy level ≥ 2 level force measuring device) and full load power (accuracy level ≥ 2 level power testing device).

Overload test:

Load to 110% of rated load, lift and lower 3 times each, with a height of ≥ 5m each time, and check for no cracks or permanent deformation.

3、 Maintenance and upkeep cycle

Daily inspection:

Clean up the debris in the steel wire rope and check the number of broken wires.

Add lubricating oil (gear reducer oil level ≥ oil level elevation line).

Monthly maintenance:

Replace the gearbox lubricating oil (55-7 oil, replace every 2-3 months).

Check the wear of the brake and adjust the brake clearance.

Annual maintenance:

Test the insulation resistance of the motor and replace the aging cable.

Verify the limit device and over roll protection function.

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