The common faults of electric hoists in operation can be classified into five categories: electrical system, mechanical structure, braking system, control circuit, and environmental factors. The following is a summary of specific faults and solutions:

1、 Electrical system malfunction

The motor does not start or runs weakly

Possible reasons: power phase loss, unstable voltage, or wiring errors; Motor winding burnt out or bearing damaged; The brake is not fully released.

Solution: Check if the power supply voltage is normal (± 10% rated voltage) to ensure three-phase electrical balance; Test the insulation resistance of the motor. If the winding is short circuited, the motor needs to be replaced; Check if the overload protector trips, reset and restart; Adjust the brake clearance to ensure that the brake pads are completely separated.

Control button malfunction

Possible reasons: poor contact or disconnection of the control circuit; Oxidation or damage to button contacts; The malfunction of the limiter resulted in signal termination.

Solution: Use a multimeter to check the continuity of the circuit and repair the broken points; Clean or replace control buttons; Check if the upper and lower limit switches have been reset or damaged.

Motor overheating

Possible reasons: Overloading operation; Wear of motor bearings or gearbox gears; Poor ventilation.

Solution: Keep within the rated capacity range of the crane; Replace bearings or gears with abnormal noise; Check the ventilation of the electric hoist to ensure good ventilation.

2、 Mechanical structural failure

Abnormal noise or vibration

Possible reasons: Wear of motor bearings or gearbox gears; Loose bolts of structural components; Track deformation or wheel deviation.

Solution: Replace the bearing or gear with abnormal noise; Tighten all bolts and check if the frame is deformed; Correct the track or adjust the wheel position.

Transmission oil leakage

Possible cause: The sealing ring between the shell and the cover is worn or damaged.

Solution: Replace the sealing ring.

The drum or pulley is stuck

Possible reasons: Bearing damage causing poor rotation; Wire rope jumping or tangled disorderly; Poor lubrication leads to rusting of components.

Solution: Regularly clean dirt and add lubricating grease; Replace damaged bearings; Organize the steel wire rope to ensure alignment on the pulley/drum.

3、 Brake system malfunction

Brake system malfunction (heavy object sliding or unable to stop)

Possible reasons: brake pad wear or spring failure; There is oil or impurities on the surface of the brake wheel.

Solution: Check the thickness of the brake pads, and replace them if the wear exceeds 50%; Adjust the brake clearance to the standard value (usually 0.3-0.5mm); Clean the surface of the brake wheel to ensure no oil stains.

The hoist slips after stopping

Possible reasons: brake wear, loose nuts, weakened springs; Dust and oil stains affect braking; The motor coupling is stuck or improperly moved.

Solution: Adjust the brake nut according to the instructions in the crane manual; Clean the braking system, remove dust and oil stains; Check and repair or replace the coupling accordingly.

4、 Control circuit malfunction

The elevator does not respond when the switch is pressed

Possible reason: The power supply is not connected; Switch circuit issues; Low voltage power supply for motor.

Solution: Confirm that the power supply is connected; Check if the internal wiring is damaged or if the connections are loose; Ensure that the power supply voltage of the motor is not less than 10% of the rated voltage.

The hoist cannot stop after running

Possible cause: Contact fusion of the contactor.

Solution: Immediately cut off the main power supply and check or replace the contactor.

5、 Malfunctions caused by environmental factors

Poor contact of sliding contact wire

Possible reasons: Poor quality of the sliding wire and harsh on-site environment may cause the plastic shell of the sliding wire to be fragile and deformed; Corrosion and failure of collector spring; Improper use of the electric hoist caused the current collector to deviate from the normal track.

Solution: Strengthen the position of the sliding line interface to ensure a smooth interface; Replace the corroded spring of the current collector and polish the carbon brush contacts; Standardize the use of electric hoists to avoid skewed pulling and lifting.

Aging, damage, and loose connections in electrical circuits

Possible reasons: Working in harsh environments such as dust, humidity, and vibration for a long time may cause the insulation layer of the wire to age and crack; The wiring screws of the terminal block are loose due to vibration and other reasons.

Solution: Regularly inspect electrical circuits and replace aging and damaged wires in a timely manner; Tighten the loose connection terminal block screws.

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