When evaluating the operation of electric hoists, the core quality issues focus on five dimensions: electrical system, mechanical structure, safety devices, operational performance, and environmental adaptability. The specific analysis is as follows:

1、 Electrical system quality issues

Motor failure

Performance: The motor does not start, runs weakly, or overheats.

Reason: Power phase loss, unstable voltage, wiring errors, burnt windings or damaged bearings.

Case: A factory experienced frequent motor burnout due to voltage fluctuations, which was resolved by installing a voltage regulator.

Testing method: Use a multimeter to measure voltage and current, test the insulation resistance of the motor, and check if the overload protector trips.

Control circuit issues

Performance: Operation failure (such as "only up and not down"), button unresponsive.

Reason: Oxidation of contactor contacts, relay failure, or poor circuit contact.

Case: Due to the aging of the control circuit at a construction site, the contactor contacts melted and the hoist could not be stopped, causing a safety hazard.

Detection method: Check the continuity of the circuit, clean or replace the control button, and test whether the limit switch is reset.

2、 Mechanical structure quality issues

Brake system failure

Performance: Heavy objects sliding or unable to stop.

Reason: Brake pad wear, spring failure, or oil stains on the surface of the brake wheel.

Case: Due to excessive brake clearance in a warehouse, the hoist suddenly slipped while lifting goods, almost causing an accident.

Testing method: Check the thickness of the brake pads, adjust the clearance to the standard value (usually 0.3-0.5mm), and clean the surface of the brake wheel.

Chain/wire rope issues

Performance: Wear, breakage, or chain jamming.

Reason: Long term use can cause metal fatigue, insufficient lubrication, or overload.

Case: A construction site suffered equipment damage due to a broken steel wire rope causing heavy objects to fall.

Testing method: Regularly check for broken wires and deformation, replace according to standards (such as GB/T5972), and ensure sufficient lubrication.

Gearbox malfunction

Performance: Stuck operation, loud noise, or oil leakage.

Reason: Gear wear, bearing damage, or aging sealing ring.

Case: A factory needs to replace the entire gearbox due to severe wear and tear on the gearbox gears, resulting in unstable operation of the hoist.

Testing method: Check the gear meshing condition, replace worn parts, and replace sealing rings.

3、 Quality issues with safety devices

Limit switch malfunction

Performance: The hook is running beyond its limit and cannot automatically stop.

Reason: The limit switch is damaged or the position is not adjusted properly.

Case: Due to the failure of the limit switch in a certain workshop, the hook collided with the end of the track, causing equipment damage.

Testing method: Test the precise triggering function of the upper and lower limit switches and adjust the position to the standard value.

Overload protection failure

Performance: The equipment does not automatically cut off power or sound an alarm when overloaded.

Reason: Overload protector setting error or sensor malfunction.

Case: Due to the failure of overload protection at a construction site, the hoist operated in an overloaded state and the motor burned out.

Detection method: Re calibrate the parameters of the overload protector and check if the sensor signal is stable.

4、 Operational performance quality issues

Deviation in lifting speed

Performance: The actual speed does not match the nominal value.

Reason: Insufficient motor power, worn gearbox, or low efficiency of pulley system.

Case: A factory had a slow lifting speed that affected production efficiency, which was later resolved by replacing the high-efficiency motor.

Testing method: Measure the lifting speed under no-load and full load conditions, and compare it with the standard value.

Excessive brake slip

Performance: The hook slides too far after braking.

Reason: Decreased brake performance or excessive load.

Case: A warehouse experienced excessive sliding due to braking, resulting in goods shaking during lifting and increasing safety risks.

Testing method: Measure the braking slip under rated load, which should not exceed V/100 (V is the distance of stable lifting at rated lifting speed for 1 minute), and should not exceed 200mm.

5、 Environmental adaptability quality issues

Impact of high temperature environment

Performance: Motor overheating, grease failure, or component deformation.

Reason: High ambient temperature or poor heat dissipation.

Case: A steel plant experienced frequent overheating of the hoist motor due to high temperatures, which was later resolved by installing a cooling fan.

Detection method: Monitor the temperature changes of the motor during continuous operation to ensure that it is within a safe range (usually ≤ 60 ℃).

Corrosive environmental impact

Performance: Corrosion of metal components and short circuit in electrical systems.

Reason: Exposure to chemicals or salt spray.

Case: A chemical plant had a chain break due to the use of a gourd in a corrosive environment, and subsequently replaced the chain with a stainless steel material.

Testing method: Check the durability of the surface coating, and if necessary, use a corrosion-resistant hoist.

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