In polarization problems, a common fault is that two diagonal corners vibrate normally while the other two diagonal corners have almost no amplitude. Possible causes include the following:
- The angle of the motor weight blocks may have changed.
- The four spring support points are not on the same horizontal line.
- The spring supports are faulty, or the spring forces are uneven and differ greatly, requiring adjustment.
- The static heights of the springs are inconsistent.
- The difference between the motor center and the coupling center at the drive end is too large when the screen is stopped.
- There is a problem with the vibrating screen exciter.
- The screen frame rigidity is insufficient or the frame has loose parts.
- When spring compression is the same, the overall rigidity of the vibrating screen is insufficient. In this case, reducing the frequency can help identify the problem.
How to Repair
Check whether the screen frame is a standard rectangle rather than a parallelogram. Check whether the spring supports were installed on the same level during design and manufacturing, and whether the selected spring stiffness is the same. Check whether the self-synchronization between the two vibrators is normal. Check whether the phase angles of the primary and secondary eccentric blocks on both side plates of the vibrating screen are consistent, because this directly affects whether the generated vibration force is uniform.
Torsional vibration occurs mostly in linear vibrating screens. The main causes include: the vibration force direction from the vibrator is offset, the spring damping system or different components are faulty, the linear screen is not placed on a level surface, and the screen surface cannot remain horizontal.
How to Repair Torsional Vibration
Check whether the spring supports of the screen can be installed on a uniform plane and whether the current compression amounts are the same. The error should not exceed 5 mm. When installing universal joint shafts, check whether the phase angles on both sides are the same. Other causes should be judged according to the specific screen type and operating conditions. For replacement of screen frames, spring supports, eccentric blocks, and related structural components, Hansheng Automation provides custom machining according to your drawings.
Small Amplitude of the Vibrating Screen
Possible causes include insufficient power supply voltage, incorrect wiring connections, and voltage drop, all of which can reduce amplitude. Too few eccentric blocks can also cause small amplitude; increasing the number of eccentric blocks may help. If the screen is driven by a vibration motor, the angle between the eccentric blocks at both ends of the motor shaft also affects amplitude. A smaller angle increases the exciting force and amplitude, while a larger angle reduces amplitude. Excessive feed volume and material accumulation can exceed the screen's capacity, causing heavy load and affecting amplitude. Unreasonable spring design can also reduce amplitude. In addition, equipment faults such as damaged motors, electrical components, or exciters may be responsible.
Large Amplitude of the Vibrating Screen
Excessive vibration force is one cause. If the damping spring hardness is too high, there is little cushioning effect, and the equipment may jump during operation. Installation problems, such as uneven ground, can also lead to large amplitude. Loose anchor bolts are another common cause; even if the screen is installed level, abnormal vibration after a period of use often indicates loose anchor bolts. Motor direction also matters; if the power or direction is incorrect, the screen may jump severely. The rotation direction of vibration motors is generally adjusted before the screen leaves the factory.
