In the evaluation of electric winches, the core of quality issues focuses on operational stability, braking performance, structural strength, effectiveness of safety protection devices, and environmental adaptability. The following is a specific analysis:

1、 Stability issues during operation

Gear and transmission system malfunction

Abnormal noise and vibration: Gear mesh clearance that is too tight/loose, bearing wear, or foreign objects inside the reducer can cause abnormal noise during operation. Long term operation may lead to gear fracture or bearing failure. For example, a certain model of winch has insufficient gear accuracy and excessive noise during operation, which interferes with the operator's attention. Therefore, it is necessary to improve the gear machining accuracy or replace high-precision gears to solve the problem.

Load fluctuation: Overloading operation (such as lifting weight beyond the rated value) can cause motor overheating, power fluctuations, and even motor burnout. Durability testing shows that after running at rated load for 4 consecutive hours, the performance degradation should not exceed 5%. Otherwise, it is necessary to optimize the motor heat dissipation design or add overload protection devices.

Defects in steel wire rope management

Disorderly arrangement: Improper arrangement of winches (such as exceeding the deviation angle of the lifting wire rope), failure or improper operation of the rope arrangement device can cause the wire rope to be tangled haphazardly on the drum, accelerate wear and increase the risk of wire breakage. For example, in a certain case, the steel wire rope was not arranged neatly, and the stacking height exceeded the edge of the drum, causing it to slide out of the drum and break the rope.

Wear and tear: Steel wire ropes are subjected to alternating loads for a long time. If the ropes with worn and broken wires are not regularly inspected and replaced, it may cause safety accidents. Industry standards require that steel wire ropes must be scrapped when the wire breakage rate exceeds 10%.

2、 Braking performance issues

Brake failure

Heating and wear: Using the brake too early, too much, or installing the brake shoes incorrectly (such as a small contact area) can cause the brake to overheat and wear excessively, reducing braking performance. For example, a winch experienced brake failure due to loose brake shoe bolts, causing the bolt head to touch the brake wheel.

Difficulty in releasing the brake: Improper adjustment of the brake lever, blockage of the hydraulic system oil circuit, or oil leakage from the electro-hydraulic pressure regulating device may cause the disc brake to be unable to release. It is necessary to regularly clean the oil filter and adjust the position of the lever.

Emergency braking response

Overload protection failure: Some winches are not equipped with an automatic cut-off function at 1.5 times the rated load, which prevents them from stopping in a timely manner when overloaded, increasing the risk of equipment damage. The durability test requires that the overload protection device must trigger an alarm or power outage within the specified time when applying 1.5 times the load.

3、 Structural strength and durability issues

Wear and tear of key components

Drum and supporting wheels: Loose bolts on the drum shell, excessive clearance between supporting wheels, or cracks on the drum shell can cause abnormal operation noise or even structural fracture. For example, a winch experienced severe vibration due to loose fixing screws of the traveling drum liner, resulting in excessive wear between the liner and the spindle.

Bearings and clutches: Improper selection of bearing models, insufficient lubrication, or improper adjustment of working clearance can accelerate wear and increase noise. When the thickness wear of the clutch plate exceeds 15% of the original value, it needs to be replaced, otherwise it may cause transmission failure.

Insufficient environmental adaptability

Temperature rise control: If the temperature rise of the motor and brake during continuous operation is too high (exceeding the ambient temperature+75 ℃), it will reduce the insulation performance and shorten the service life. The infrared thermometer monitoring shows that after running in a high temperature environment for 2 hours, the motor temperature of a winch reached 90 ℃, exceeding the standard limit.

Corrosion resistance: In humid or corrosive environments, winches that do not use explosion-proof motors or stainless steel components are prone to malfunction due to electrical short circuits or structural corrosion.

4、 Effectiveness of safety protection devices

Depth indicator and signal system

Indication error: Failure of the depth indicator system may result in over rolling or squatting accidents of the lifting container. For example, a winch failed to issue an over roll signal in a timely manner due to a malfunctioning depth indicator sensor, causing the container to collide with the derrick.

Signal interruption: Poor sound and light signal system or communication errors between operators and signal workers may lead to misoperation. Industry standards require that the dot signal must be installed in the driver's closest position and have a loud sound.

Missing protective device

Damaged rope guard: When the steel wire rope is not arranged neatly, the rope guard can prevent the steel wire rope from slipping out of the drum. If the rope guard is missing or deformed, it may cause a broken rope racing accident.

Emergency stop button failure: The operation button may be damp, short circuited, or the contact of the magnetic starter may be burnt, which may prevent the machine from stopping in emergency situations. For example, a winch had its stop button not reset to its original position, causing the motor to continue running and overheat and burn out.

5、 Standardization of operation and maintenance

Operator skills

Overspeed/Overloaded Operation: In pursuit of efficiency, operators may overspeed or overload the winch, resulting in abnormal changes in gear mesh stiffness, increased noise, and even rope breakage accidents. For example, a winch experienced severe pitting corrosion on the gear surface due to overload operation, and the operating noise reached 95dB (A), exceeding the standard limit.

Violation of regulations: If the motor fails to power on and release the brake when the load is lowered ("releasing the car"), it will accelerate the wear of the brake band and pose a risk of loss of control.

Insufficient maintenance and upkeep

Poor lubrication: Failure to regularly add lubricating oil to components such as gear pairs and bearings can lead to increased wear and noise. For example, a winch experiences frequent jamming during operation due to insufficient lubricating oil in the reducer, resulting in severe adhesion on the gear surface.

Failure to replace components in a timely manner: Failure to replace vulnerable parts such as brake shoes and clutch plates after wear may result in brake failure or transmission failure. Industry standards require that the decrease in friction coefficient of brake shoes should not exceed 20%, otherwise replacement is required.

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