Hammer mill malfunction and troubleshooting
See the below table for some tips about Hammer mill malfunction and troubleshooting.
| Trouble |
Cause/s |
Solution/s |
| Machine is started with difficulty. |
Too low voltage
The lead wire section area is very small.
Fuse burns off easily.
The presence of the raw materials inside the mill chamber; the mill chamber should be completely discharged.
|
Avoid turning up the machine at peak hours of power consumption. Restart the machine.
Replace the old lead wire with a new one.
Use a bigger compensator.
Use a new fuse in accordance with the motor load. |
| Motor overhead; The power is cut off
|
The motor runs in two phases.
The motor coil has a short circuit.
There is overload in the long-term. |
Connect the other phase and continue to run in three-phase.
Repair the motor.
Run the machine under the rated load. |
| Severe vibration in the hammer mill |
There is an error in the hammers array.
Every two opposite hammers are of different weights.
Some hammers are locked, they are not free.
Imbalance of other parts on the rotor;
The main shaft is bent.
The bearing is worn.
The pin shaft of the hammer is worn.
There is no distance between two halves of the coupling.
Couplings are misaligned.
Insufficient strength of anchor bolts.
|
Install hammers in accordance with their arraying diagram.
Keep a 5-gram weight difference between two opposite hammers on radial when replacing the old hammers with new ones.
The hammers should be freed.
Check the rotor in terms of imbalance.
Align the shaft or replace the old shaft with the new one.
Replace the old bearing with the new one. |
| Abnormal voice is heard from hammer mill.
|
A metal part or stone has entered the machine.
Some inner parts have been dismounted or broken.
There is a small distance between the screen and hammers.
Rotor has been displaced.
The ball bearing has probably broken.
|
Turn off the machine to remove hard materials.
Turn off the machine to check and replace spare parts.
Keep the distance between the hammer and screen in accordance with the instruction.
Check and do the required adjustments. |
| Low efficiency |
The motor is of a lower power.
Sever wearing of hammers;
Uneven feeding;
The raw materials’ moisture and fat content is very high.
Using inappropriate screen;
Dust filter is blocked.
Low percentage of open area of the screen.
Mesh pores are blocked.
|
Check the motor and repair it.
Change the hammers or replace the old hammers with the new ones.
Feed materials evenly.
Dry the raw materials and enter with <8% fat.
Replace the inappropriate screen with an appropriate one.
Clean filter bags, or replace the old filter bags with the new ones.
Choose a high open area screen.
Check dust collector, jet filter, and induced draught (ID) fan.
The suction path should not be torn. |
| Feeding inlet has been removed. |
Conveying pipe is blocked.
Screen holes are blocked
The grinding plate position does not match the rotor rotation. |
Remove the blockage.
Clean the holes of the screen or replace the old screen with a new one.
Change the position of the guiding plate or running direction of the motor.
Use glue around the mesh. |
| Coarse mesh of the product
|
Severely worn or damaged screen;
The screen and its frame do not touch in a proper way, or there is a large side gap. |
Repair the screen or replace the old screen with a new one.
Turn off the machine and repair or tighten the screen and frame.
|
| Bearing has been overheated. |
Misalignment of the main shaft and motor;
Too much or less volume of lubricating oil has been used.
The bearing is damaged.
The main shaft is bent, or the rotor is imbalanced.
The motor has run overloaded for a prolonged period.
Inappropriate lubricating oil has been used. |
Adjust the motor; it should be concentric with the main shaft.
Change the oil. Add oil in accordance with the instruction.
Replace the damaged bearing with a new one.
Balance the rotor after aligning the main shaft.
Reduce the volume of the feeding.
Use suitable lubricating oil.
|
* The ball bearings’ condition should be checked every day. Control all loosen bolt and nuts on a daily basis. Use grease every day and check the screen health before each production and control the bearing and coupling slippage every day before production, and present a written report.
* The mill hammers should be replaced considering the corrosion amount. The distance between the hammers and screen should not exceed 8 mm.
* Tighten the screws of the electric motor every week.
* Check the grease level in each production and use grease if needed. The ball bearings will be corroded or broken if there is high vibration. Therefore, the balance should be checked and the hammers should be tested. The operator should necessarily be a specialist.
* Warning: All machinery should be repaired, modified, and regulated after the main power board is cut off
