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Common problems and troubleshooting measures of metal conveyor belts

Sep 10, 2021

1 Motor failure
There are two manifestations of motor failure. One is that the motor cannot start or slows down immediately after starting; the other is that the motor is overheated.
1.1 The motor cannot start or slows down immediately after starting
There are five reasons that cause the motor to fail to start or to slow down immediately after starting:

(1) Line failure;

(2) The protection electric control system is locked;

(3) Improper installation and adjustment of speed (broken belt) protection;

(4) Voltage drop;

(5) Contactor failure;
There are five solutions to these five causes of failure:

(1) Check the line;

(2) Check the protection of deviation, limit, parking along the line, etc., and reset the accident after handling the accident;

(3) Check the speed measuring device;

(4) Check the voltage;

(5) Check the overload relay;
1.2 The motor is overheated
There are five reasons for the overheating of the motor:
(1) The operation is overloaded due to overload, excessive length, or jamming of the conveyor belt;

(2) Due to poor lubrication conditions of the transmission system, the power of the motor increases;

(3) Coal dust accumulates in the air inlet of the motor fan or the radial heat sink, which deteriorates the heat dissipation condition;

(4) In the case of dual motors, the mailed motor characteristic curve is different or the drum diameter is different, which makes the shaft power distribution uneven;

(5) Reasons for frequent operation;

For the above five reasons, there are five solutions:
(1) Measure the power of the motor, find out the cause of overload operation, and deal with it symptomatically;

(2) Replenish lubricant in time for each transmission part;

(3) Remove coal dust;

(4) Equivalent power motors are used to make the characteristic curve consistent, and the power of the two motors can be reasonably distributed by adjusting the oil filling amount of the coupler;

(5) Reduce the number of operations;

These methods can reduce the overheating of the motor.

2.2 Skidding

There are three reasons for skidding:

(1) Insufficient oil injection in the hydraulic coupler;

(2) The conveyor is overloaded;

(3) The conveyor is jammed;

There are three solutions for three reasons:

(1) Unscrew the oil filling plug with a wrench, and replenish the oil according to the regulations;

(2) Stop the conveyor and deal with the overloaded part;

(3) Stop the conveyor and deal with the stuck fault; these three methods are very helpful to solve the slip problem.


2.3 Overheating

The main cause of the overheating of the fluid coupling is poor ventilation and heat dissipation. The main solution to this situation is to clean the ventilation mesh and remove the dust accumulated on the outer cover. This can increase heat dissipation.

2.4 The motor rotates and the coupling does not rotate. There are three reasons for this situation:

(1) There is no oil or too little oil in the hydraulic coupling;

(2) The fusible plug is sprayed with oil;

(3) The voltage drop of the power grid exceeds the allowable voltage range;

There are two solutions to these three situations:

(1) Unscrew the oil filling plug, and add oil or replenish oil according to the regulations;

(2) Unscrew the fusible plug, refuel or replace the fusible plug alloy plug. It is strictly forbidden to replace fusible plugs with wooden plugs or other substances.

2.5 Shock sound when starting or stopping

The cause of the impact sound of the liquefied coupling starting or stopping is the excessive wear of the elastic coupling material on the hydraulic coupling. The solution is to remove the connecting bolts and replace the elastic material.

3 Reducer failure

3.1 Overheating

reason: 
(1) Too much or too little oil in the reducer;

(2) The oil has been used for too long;

(3) Deterioration of lubrication conditions, causing damage to the bearing;

(4) The cooling device is not used;

Solution:
(1) Fill oil according to regulations;

(2) Clean the interior, change the oil in time, repair or replace the bearings, and improve the lubrication conditions;

(3) Connect the water pipe and use circulating water to reduce the oil temperature;

3.2 Oil spill
There are three reasons for oil leakage:

(1) Loose screws on the joint surface;

(2) The seal fails;

(3) Too much oil;

Solution: 

(1) Tighten the screws evenly;

(2) Replace the seals;

(3) Inject oil according to the specified amount

3.3 Shaft break

The main reasons for shaft breakage are:

(1) The design strength of the high-speed shaft is not enough;

(2) The high-speed shaft is not concentric;

(3) Shaft breakage in the case of motor drive;

The solution to this situation:

(1) Immediately replace the reducer or modify the design of the reducer;

(2) Carefully adjust its position to ensure the concentricity of the two shafts;

(3) The amount of oil in the hydraulic coupler should not be too much;

4 Conveyor belt failure

4.1 Belt deviation

(1) Improper installation of the roller set.
When the verticality error between the installation position and the center line of the conveyor is large, the running speed V of the idler roller is not parallel to the running speed of the belt, which can be decomposed into a horizontal speed VX and a longitudinal speed VY. VX drives the belt to move horizontally, and VY makes the belt move. Lateral movement, resulting in deviation. The direction of deviation is related to the inclined position of the supporting roller group. This can be eliminated by adjusting the position of the roller group or by installing a self-aligning roller group.

(2) Improper installation of the front and rear rollers
When the head drives the roller or the tail redirects to the axis of the roller. When the roller is not perpendicular to the center line of the conveyor and the roller is skewed, the tightness of the tape on both sides of the roller is inconsistent, and the traction along the width direction is also inconsistent, and the conveyor belt is tight. The side moves off the track. The front and back positions of the roller bearing seat can be adjusted. If the head roller deviates to the right, the right bearing seat should move forward; if the left side deviates, the left bearing seat should move forward; the adjustment method of the tail roller is just the opposite of that of the head roller. When the deviation is severe, the rack must be reinstalled.
(3) Improper joints
When running, the maximum deviation is at the joint. Wherever the joint is turned, the deviation will occur. It is caused by uneven tension on the conveyor belt due to uneven ends of the conveyor belt joints, crooked belt buckle nails, or the incision of the conveyor belt is not perpendicular to the belt end. Cut the conveyor belt interface straight, re-gluing or re-tapping the belt buckle.
(4) Improper tensioning.
When idling, the deviation is weakened or normal after adding materials. This is caused by slack or excessive initial tension of the conveyor belt. If the tension is too high, the belt will float away from the roller during operation; if the tension is too low, the friction between the roller and the belt will decrease, the belt's longitudinal forward power will decrease, and the lateral movement resistance will decrease, causing deviation. Appropriate addition or reduction of gravity can be adopted to solve the problem. For belt conveyors with spiral tension or hydraulic tension, the tensioning stroke can be adjusted to solve the problem.
(5) The outer surface of the drum has processing errors, sticky materials or uneven wear.
When the abrasion is uneven, the surface of the roller is conical, which makes the conveyor belt deviate to the larger diameter side. To clean up the sticky materials on the surface of the roller, check the cleaner frequently and manually clean the materials on the return conveyor belt; re-encapsulate the rollers with large processing errors and uneven wear.
(6) The position of the blanking port is incorrect.
The idling is normal, and the load will run away. This may be due to the fact that the material falling point is not in the middle of the conveyor belt, the distribution is biased to one side, and the belt is deflected by the eccentric force. Change the position or structure of the baffle at the blanking port so that the blanking is located in the middle of the conveyor belt.
(7) There are quality defects.
The quality of the conveyor belt is poor, the internal tensile material is not uniformly arranged, or the edges are severely worn, the synthetic centerline of the belt tension does not coincide with the geometric centerline of the belt, or the use time is too long, plastic deformation occurs, the surface is not straight, and both sides of the belt The length is different, and the pulling force received is inconsistent, causing the deviation position to be unfixed. Just repair or replace the tape.
Discoloration and dryness of bearing grease
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