ANALYSIS OF COMMON FAILURES OF ELEVATOR TRACTION MACHINE AND TROUBLESHOOTING METHODS丨Potensi Elevator

author: Potensi-Ella
03/11/2021
1. Phenomenon: The horizontal vibration of the traction machine is out of tolerance, and the vibration frequency is consistent with the motor speed.

             Reason: ①The mounting surface of the traction machine base is not flat, causing the base to be forced to deform and destroying the geometric accuracy of the traction machine. ②The coaxiality of the motor shaft and the worm shaft is too poor, which mostly occurs in the traction machine with the elastic coupling seat type motor structure.

           Remedy: ①Remove the wire rope, loosen the anchor bolts, make the traction machine in a free state, and readjust the mounting surface of the traction machine base. If the installation structure with a rubber plate under the base does not need to take off the wire rope, just adjust the compression of the rubber plate at the foot. ②Recheck and adjust the coaxiality between the motor and the worm.

2 Phenomenon: The motor makes a rhythmic drum beat, and the frequency is consistent with the motor speed.

            Reason: Generally, it is caused by the inclination of the traction machine base installation that the motor shaft moves forward or backward to the limit position, and the step surface of the motor shaft and the end surface of the sliding bearing are caused by friction.

          Remedy: Adjust the base to make the traction machine in a horizontal position or take forced measures to prevent the motor shaft from moving forward and backward.



3 Phenomenon: When the brake of the traction machine brakes, there is an obvious sense of impact in the car, that is, a pause.

            Reason: ①The gap between the brake shoe and the brake wheel is too large, and the international regulations are less than 0.7mm. ②The axial clearance of the worm shaft is too large. ③The meshing backlash of the worm gear pair is too large, which is likely to happen to the traction machine that has been used for many years.

          Remedy: ①Adjust the brake release gap to the standard requirements. ②Check whether the lock nut of the worm thrust bearing is loose. If there is no looseness, the gasket should be thinned to make the clearance meet the factory standard requirements. ③There are many ways to adjust the center distance of the worm gear pair, such as bracket type, oblique block type and eccentric type, but the backlash can be adjusted to the factory requirements.


4 Phenomenon: The whole machine is noisy, and the noise in the machine room exceeds 80dB(A).

          Reasons: ① The motor windings are faulty and produce high-frequency hum, which mostly occurs when the windings are running at low speeds, and sometimes also when running at high speeds, which is a motor manufacturing problem. ②The contact spot of the worm gear pair is biased toward the screw-in end or the worm gear tooth surface has a poor finish (which is likely to occur on the scraped tooth surface). ③The thrust bearing raceway on the worm shaft is of poor quality. ④The oil passages of the worm sliding bearing and thrust bearing are blocked, causing poor lubrication of the bearing. ⑤The positioning end face of the thrust bearing is not perpendicular to the axis of the worm, which makes the bearing raceway deviate.

         Remedy: ① It should be inspected and repaired by electric motor professionals. ②Adjust the contact area of the worm gear pair to deviate to the screw-out end. Generally, the worm gear should be replaced if it is caused by scraping the tooth surface. ③ Replace qualified bearings. ④ Unblock the oil circuit. ⑤ Repair or replace the bearing seat.


5 Phenomenon: the tooth surface of the worm gear wears too fast or the glue is broken.

            Reason: ①The lubricating oil is not clean. ②Improper selection of lubricating oil or mixed use of oil makes lubricating oil ineffective. ③The surface finish of the worm gear is poor. ④The oil level is low.

           Remedy: ①Clean the oil tank and replace with clean new oil. ②Worm-driven traction machine should use suitable worm gear oil, and different oil products must not be mixed. ③The tooth surface of the worm should be grinded, and the surface roughness should not be greater than Ral.6. ④ Increase the oil level to the specified height.

6 Phenomenon: The temperature of the fuel tank is too high, approaching or exceeding 85°C.

            Reason: ①The lubrication of the worm sliding bearing and thrust bearing is poor, usually because the oil circuit is blocked or the oil level is low. ② The contact spot of the worm gear pair is biased to one end, making the side clearance too small. ③Lubricant failure or improper oil selection.

          Remedy: ① Unblock the oil circuit and fill up the oil level. ② Make the contact spots of the worm gear set in the correct position. ③ Change the specified worm gear oil.

7 Phenomenon: The oil leakage at the extension end of the worm exceeds the standard qualified product requirement of 150 c㎡/h.

            Reason: failure of shaft end seal or improper assembly.

           Remedy: ① For packing type sealing device, the compression bolt should be adjusted first, if it still cannot be eliminated, new asbestos rope should be replaced. ②As for the mechanical seal structure, the static ring is generally deformed due to the unclean end faces of the dynamic and static rings or the poor finish of the end faces and improper assembly. If it is damaged, replace it. ③The J-type skeleton seal ring device is mostly O-shaped spring to open the buckle or reverse the direction.

  8 Phenomenon: When the traction machine starts, the brake is released slowly or cannot be released.

            Reason: ①The air gap of the electromagnet is too large. ②The coil power supply voltage is less than 110V. ③The hinge shafts of the brake arm are severely corroded.

           Remedy: ①Adjust the air gap to the design requirements. ②Increase the power supply voltage to 110V. ③Grind the pin shaft and hole and add proper lubricating oil.


9 Phenomenon: When the elevator changes from high speed to low speed, the traction wheel shakes, and the box makes an impact sound, and there is a strong sense of suspension in the car.

           Reason:This phenomenon is more common in AC two-speed elevators, and the switching time is too short when changing from high speed to low speed.

         Remedy:Adjust the control time of the time relay appropriately.
10 Phenomenon: The output voltage signal of the tachometer generator of the intermodulation traction machine fluctuates greatly.

              Reason: ①The quality of the tachogenerator is poor. ②The coaxiality between the output shaft of the traction machine and the shaft of the generator is poor.

            Remedy: ① Replace a qualified generator. ②Adjust the coaxiality to the requirement (except for the structure of belt dragging).

11 Phenomenon: The fan does not start when the temperature of the motor with fan reaches the specified value.

              Reason: ①The temperature control relay is out of order or damaged. ② The thermistor fails.

             Remedy: ①Repair or replace the temperature control relay. ② Directly supply power to the fan so that the fan is in a normally open state.