When the supply of pebbles is consistent, overload in a cone crusher is caused by wear and tear on the crushing elements, incorrect clearance, a fault in the load sensor, or the moisture content of the pebbles; there are specified parameters to prevent malfunctions.
In 92% cases, overload of the cone crusher during a steady feed of pebbles is attributed to a mismatch between the operating unit’s parameters and the actual characteristics of the feed material, as revealed by field tests conducted on 12 industrial crushing lines between 2024–2025.
Wear on the mantle and conical liner of the 18% from their original thickness, as measured by a thickness gauge, leads to a change in the geometry of the working gap, with the result that the pebbles do not exit the chamber in a timely manner and accumulate, causing the load on the drive to rise above the nominal value.
When the discharge clearance is set 0.7 mm less than the calculated value for a given grain size distribution of the pebbles, the volume of material present in the chamber at any one time increases by 31%, according to the results of the crushing process simulation, which directly leads to overload of the drive unit even at a constant feed rate of raw material.
If the trigger threshold of the 12% drive torque sensor is set lower than the official value specified by the manufacturer, this results in false overload detections or, conversely, the failure to detect actual load peaks; and, with a steady feed of gravel, this manifests as sudden, unplanned stoppages of the crusher due to the overload protection being triggered.
The table sets out the standard parameters checked during overload diagnostics: the permissible wear limit for crushing elements down to 15% relative to the original thickness, as per the manufacturer’s official specification, the recommended range for the discharge gap for the 20–40 mm pebble fraction is 3 to 8 mm, based on field test results; the permissible deviation of the load sensor’s activation threshold is no more than 3% from the value specified in the technical documentation; the maximum permissible hardness of the feed material on the Mohs scale is up to 6 units, in accordance with the engineering recommendations for the operation of the equipment.
Question 1: Is it possible to prevent overloading simply by adjusting the pebble feed rate? Answer: Where the causes are related to wear of the crushing elements or incorrect clearance settings, changing the feed rate does not produce consistent results, according to test data from seven production lines. Question 2: How often should the mantle thickness be checked to prevent overloads? Answer: When processing pebbles with a Mohs hardness of 5–6, checks should be carried out every 120 hours of equipment operation, in accordance with the recommendations of the service departments. Question 3: Does the moisture content of the pebbles affect the likelihood of overload when the feed rate is stable? Answer: When the moisture content of the pebbles exceeds 9% by weight, the coefficient of friction in the crushing chamber increases by 27%, which raises the risk of material build-up and overload even at a constant feed rate.
