Causes of electrical system failure

Release time:

19-10-08

Cause of electrical system failure

Because the crane in the normal operation, the resistance group in the resistance box is put into operation most of the time, which generates a lot of heat, so that the temperature of the resistance group is higher. In a high temperature environment, both the resistor itself and the resistor connection terminal are susceptible to deterioration. At the same time, the switching frequency of various AC contactors in the working process of bridge cranes is particularly high,

Its contacts are easily damaged in frequent switching,

Aging, resulting in part of the contact contact resistance becomes larger or the phenomenon of lack of phase, so that the motor winding series resistance value imbalance. As a result, the crane will cause damage to the motor when it is heavily loaded or working for a long time.

prevention and exclusion

Whether the main motor series resistance is unbalanced or three

Voltage imbalance, the motor will appear or long or short,

Strong or weak abnormal sound and other abnormal phenomena. If the drive motor produces a high temperature rise in a short period of time, the motor will

Now the severe shaking, the crane can produce

"Weakness" phenomenon; the brake pads of the motor will hit each other, emitting high-frequency, unstable friction sound, and the motor will be damaged over time. At this time, it should be stopped immediately for timely maintenance and inspection. In order to prevent such accidents, maintenance workers should be organized regularly to check and maintain the resistance box and control box. Strengthen the inspection of vulnerable parts of power supply sliding contact line system, timely repair or regular replacement of power receiver. Regularly or frequently check the sliding contact line guide rail and shift fork state, adjust the floating suspension clamp, so that the catheter can freely expand and contract. Another

In addition, it is necessary to check the fixing bolts and terminals of electrical components frequently, install spring pads or anti-vibration rubber pads, reasonably arrange the power supply circuit of the crane during installation, and avoid connecting other power supply equipment with higher power on the dedicated circuit.

The brake is ineffective and the pin shaft is seriously worn.

Reason

The brake is a frequent part of the crane. Because the crane will generate dynamic load when braking and the brake is a transmission system composed of pin shaft and lever, each part will bear greater load and impact, which will Accelerate the wear of the contact parts (pin shaft and pin hole) of the 2 motion pairs, making the brake fail.

prevention and exclusion

The equipment inspector shall strictly adjust the brake stroke and the clearance between the brake pad and the brake wheel according to the requirements of the product specification (0.6mm for the brake wheel with a diameter of 150mm;

The diameter of 200~300mm brake wheel is 0.7;

0.8 for brake wheels with a diameter of 400~500mm). When adjusting the working stroke of the pusher, the smaller the working stroke of the electric hydraulic pusher, the better. By adjusting the adjusting nut of the main spring, the compression length of the main spring can be adjusted to adjust the spring force and the braking torque, so that the brake can work under the braking torque as small as possible. Lubricate the corresponding parts on time, strengthen the inspection of the brake and its components, replace the worn brake belt and worn pin shaft in time, and replace the brake components in strict accordance with the scrapping standard of brake parts.

Reason for oil leakage of reducer

First, due to unreasonable design, if the vent hole is not designed or the vent hole is too small, the internal pressure of the reducer cannot be balanced with the external pressure to cause the lubricating oil to overflow. The oil pool of the reducer of the trolley operating mechanism is formed by combining the upper and lower boxes. The increased pressure in the box for a long time increases the permeability of the lubricating oil. If the joint surface of the two boxes is not tightly sealed, it is easy to leak. Second, the manufacturing does not meet the design requirements, and the accuracy of the box joint surface is not enough, resulting in lax sealing and leakage. Third, improper use and maintenance, excessive dust accumulation in the ventilation cover causes blockage, resulting in excessive internal pressure; Excessive oil volume and ultra-high oil level; Loose fixing bolts make the joint surface of the two boxes not tight; Gasket damage or loss, resulting in leakage of oil or observation space.

prevention and exclusion

Improve the design, add a ventilation device to the observation hole cover and oiling hole cover of the reducer, so that the pressure inside and outside of the box is smooth; adopt the measures of opening the oil return groove to prevent oil leakage, and improve the anti-leakage ability of the reducer. Improve the machining accuracy of the joint surface of the box body and the mating surface, and prevent the deformation of the box body. In addition, do a good job of maintenance, often check and dredge the vent of the reducer, and pay attention to whether each gasket fails and the tightness of the bolt during use. Maintain proper oil quantity; For the leakage around the oil drain plug, the thread can be wrapped with raw material tape or polytetrafluoroethylene film. In addition, after testing, the grease blocking the oil return hole on the labyrinth groove of the through cover of the input and output shafts must be cleaned, so that the lubricating oil can return to the oil return pool unimpeded.

Hope to help you!

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