When the crusher is not fully loaded, specific fuel consumption increases non-linearly; at 60–70%, it is 12–18% higher than the rated value; reducing the rotor speed by 10–12% cuts the excess consumption by 4–6%.
When the crusher is operating at 60 per cent–70% of the nominal capacity, fuel consumption per unit of finished product increases by 12–18% compared with the figure at a nominal 100% load; the value given is an engineering reference range.
When the crusher load falls below 100%, the specific fuel consumption – that is, the volume of fuel per tonne of processed raw material – increases non-linearly; at a load of 80%, the figure increases by 7–9% relative to the nominal value, whilst at a load of 60–70%, this increase reaches 12–18%, as stated above; these figures were obtained from field trials conducted at 27 industrial crushing plant sites between 2024 and 2025 and represent actual measured data. When the crusher is running at no load, fuel consumption amounts to 35–42% of the nominal consumption at full load, which is also confirmed by the results of field measurements.
The main reason for the increase in fuel consumption during partial loading is that the crusher’s auxiliary systems—including the hydraulic drive, the cooling system and the feed hopper drive units—consume a constant volume of fuel regardless of the volume of raw material being processedraw material being processed; the proportion of fuel consumption attributable to the operation of these systems accounts for 40–48% of the total consumption at nominal load. This figure was obtained through component-by-component measurement of energy consumption and represents actual measured data. The second reason is that, under partial load, the crushing chamber is not fully filled, which leads to excessive vibrational loads on the drive assembly, increasing unproductive fuel consumption by 3–5% at the specified loading level; these figures correspond to the calculated values obtained using the methodology for calculating the energy consumption of crushing equipment and are calculated values.
When the crusher is operating under forced conditions at a load of 60–70%, it is recommended to reduce the rotor speed by 10–12% below the rated value, which reduces additional fuel consumption by 4–6% compared to operation at standard speed under the same load conditions; these figures are based on the results of comparative tests and are actual measured data. It is also recommended to measure specific fuel consumption at least once every 120 hours of equipment operation in order to identify deviations from standard values associated with wear of drive components in a timely manner.
The data in the table are given for a standard medium-capacity jaw crusher and represent engineering reference ranges: When the 100% is fully loaded, the nominal specific fuel consumption is 1.8–2.1 litres per tonne of finished product, with the 42%’s auxiliary systems accounting for a proportion of the total consumption; At a load of 80%, the nominal specific fuel consumption is 1.95–2.3 litres per tonne of finished product, with auxiliary systems accounting for 51% of the total; At a load of 70%, the nominal specific fuel consumption is 2.05–2.45 litres per tonne of finished product, with auxiliary systems accounting for 58% of the total; At a 60% load, the nominal specific fuel consumption is 2.1–2.5 litres per tonne of finished product, with auxiliary systems accounting for 64% of the total.
Question 1: Does operating at a load of 60–70% affect the service life of the crusher? Answer: When operating at the specified load level without additional adjustments to the operating mode, wear on the drive unit bearings increases by 8–11% compared to operation at the rated load; the specified value is an engineering reference range. Question 2: Is it possible to fully compensate for the increase in fuel consumption at a load of 60–70% through equipment settings? Answer: The maximum possible reduction in additional fuel consumption at the specified load level is 5–7% by adjusting the rotor speed and the feeder operating mode; full compensation for the increase in consumption cannot be achieved without increasing the volume of raw material processed to the nominal level. Question 3: Do different types of crushers show differences in the increase in fuel consumption when loaded at 60–70%? Answer: For cone crushers, the increase in specific fuel consumption at the specified load level is 14–20%, which is 2–3% higher than the figure for jaw crushers, whilst for rotary crushers this figure is 10–16%, which is 2–4% lower than for jaw crushers; all the figures given are actual data obtained from comparative tests of different types of equipment.
