High load efficiency
Particularly with heavy loads that need tools to maintain stable operation over the long term, load efficiency of equipment is vital in the mining business. Synchronous motor’s high load efficiency renders it critical equipment for mine operation. When thinking of the motor’s power output, first, the synchronous motor should be able to preserve a load efficiency of at least 90%. For a 60% loaded motor, the motor on a big metal mine saves roughly 2 million KWH of electricity yearly and cuts the operating expense by 18 percent.
Technically, many appliances have started to be fitted with sophisticated temperature control systems as synchronous motor technology continually advances so that in the event of overload the engine could keep high working efficiency. In 2019, to give one example, a mining behemoth installed a coolant temperature control system on the synchronous motor of its principal mining machine, lowering the motor failure rate by 15% and also decreasing the wear and tear received from continuous overload running. Furthermore, by perfecting the motor’s starting mode (for example, by using a soft starter), the present impact of the motor can be efficiently lowered, therefore choking down the influence on the power system and further enhancing the long-term load bearing capacity of the machine.
Economically speaking, the motor’s load efficiency has a direct impact on the return on investment of the whole production system. One coal mine has, for instance, almost 3 million yuan yearly saved in electric cost thanks to precise debugging and load monitoring of synchronous motors. Most significantly, the mine’s cost of production per ton of coal has greatly decreased by bettering load efficiency, thus increasing its marketability.
Precise speed control
Among synchronous motor applications in mining equipment, one of the most important advantages is that it can effectively control the speed. In the crushing, transporting, and screening processes, equipment is required to maintain a high-speed operation precision; otherwise, production efficiency and quality of products will be affected. For instance, applying a synchronous motor in an experiment on the ore crusher, the equipment’s speed error is kept at ±0.5%, while the speed fluctuation error of the ordinary motor can be up to about 2%, resulting in output fluctuations and irregular wear.
Real-time monitoring system is extremely important in the process of obtaining accurate speed control. By integrating high-precision encoders and feedback control technology, the system is able to correct the operating status of the motor in real time, maintaining the mining equipment at the desired speed under conditions of variable loads. As a sample of taking a large mine’s conveys system as the example, using a synchronous motor with high precision, it keeps conveyor belts at a constant speed, thus eradicating the condition of ore piles up due to variations in speeds, and by enhancing production efficiency by 10%.
On economic advantage, as for enhancing mine production’s automatin degree and reducing maintenance charges caused by abrasion excessively, precise speed regulation also does well. A mining company in 2020 achieved a 20% reduction in machine breakdown by applying high-accuracy synchronous motors combined with a real-time control system. In addition, precise control of speed further enhances the ratio of energy saved by the motor, which leads to further reducing energy consumption and operating costs, statistics show system optimization after the saving of a maximum of 500,000 KWH of electricity annually, ROI was enhanced by 14%.
Technically speaking, accurate speed control is not only the capability of the motor itself, but also the fine tuning of the control system. For example, after the optimization of the crusher control system of a mining enterprise, it uses the most advanced digital control technology, which makes the speed regulation of the motor smoother, and can adjust to the change of the ore texture in an effective manner, and improve the controllability of the production process. After optimization, the failure rate of the equipment was decreased by 25% as indicated by the operator, and the stability of the production process was guaranteed.
Power factor compensation
This demand for electrification from mining enterprises is en family, and it is subject to a reactive power loss when the motor equipment is running, such as in the case with an induction motor. A synchronous motor is the optimal solution for this power factor correction problem, enhance energy utilization, and reduce operating costs. In the case of a big copper mine with synchronous motor application in the main transmission system, the overall power factor was raised from 0.76 to 0.95, thus reducing reactive power loss by approximately 27 million KWH per year, an equivalent cost-saving of about $2.4 million.
In terms of technical parameters, the power factor of the usual induction motors is from 0.7 to around 0.85, and synchronous motors can adjust their excitation current to stabilize the power factor at above 0.9. In 2022, a mining company undertook a grid optimization program that resulted in 45% less reactive power compensation equipment use and reduction in transformer overloads, thereby extending equipment life by about 30%.
From the economic standpoint, better power factor directly relates to reduced electricity costs to enterprises. Data indicated that an iron mine in 2021 realized a 15% cut in the annual electricity bill after synchronous motors compensated for the power factor, with an ROI raised to 23%. The other pertinent issues were improved grid voltage stability by 18% and reduced voltage fluctuation-caused equipment failure rate.
What is then the practical difficulty that modern induction motors have in effecting the power factor compensation as do synchronous motors?The IEEE 519-2020 standardclearly states that an installation of static VAR compensator (SVC)**is usually necessitated by the enterprises when the industrial load power factor dips below 0.8. In contrast, synchronous motors can naturally share the task of reactive power compensation. One mining business upgraded conveyor motors at the concentrators in 2020 to synchronous motors and avoided maintenance on equipment for reactive power compensation, thus saving $40,000 per unit for the year and lowering periods of downtime for the equipment.
In true applications, the compensation power factor effects are far greater than just some savings in electrical bills. A mine in Chile in 2022 reduced the congestion trips of its power system by 62% in three months of synchro-motor operation. This happened because compensation for power factor reduces reactive power flow, thereby stabilizing the whole power system, thus lessening frequent adjustments with equipment. The mine reduces approximately $800,000 in maintenance cost per year in contrast to conventional alternatives, hence greatly enhancing the equipment life.
Low maintenance cost
Since mining equipment tends to operate for extended periods against heavy loading, maintenance costs are critical to determining the feasible operation of the equipment. Structural design of synchronous motors minimizes maintenance requirements compared to asynchronous motors, and that has been a major consideration by mining firms in this regard. An example is a North American gold mine that reported that after a synchronous motor was installed on its crusher, the average maintenance period reduced from two times a year to once every four years, thus saving more than $1 million on maintenance every year.
From the technical aspect, the synchronous motor has the Brushless Excitation System which gives the advantages of less brush wear and contact resistance issues as compared with the carbon brush excitation system thus making maintenance cycle about three times more.
A mine in 2021 conducted cost analysis of maintaining brushless synchronous motors with the traditional ones, and it was shown that the annual cost maintenance of synchronous motors was only 35% as much as that of the old traditional motors.
Reduction of base maintenance cost is not only true from the point of view of direct equipment maintenance; it has further indirect economic impacts, because equipment downtime results into losses in production. As an example, in 2022, a mining company found that their ore transfer system with synchronous motors now experiences reduced annual downtime by 180 hours, thus ensuring almost a 4.7% increase in production efficiency with revenues of about $5 million.
The GB/T 2900.25-2021 standard makes mention of the bearing failure rate of the asynchronous motor as around 0.65% while to 0.2% with the synchronous motor, thanks to the advantage of the best Permanent Magnet Rotor and a better cooling system conveyor. The downtime of critical equipment gets reduced directly with this change to synchronous motor technology for a mine in 2023 by approximately 70%.
What makes synchronous motors bring down their maintenance cost? The core rationale is in structure optimization. The induction motor, for example, requires a constant change of carbon brushes, cleaning brush dust as well as maintaining the field winding, while in the case of a synchronous motor, the absence of dust intrusion makes extended life possible owing to having a closed stator winding. When an Australian miner changed its underground mining system in 2020 to include synchronous motors, its MTBF increased by almost double from 7,500 hours to 15,800 hours.
More important is that the saving in costs on maintenance is not only in their daily upkeep; it also has significant parts in the long-term return on investment for the equipment. For instance, an international mining group massively replaced all its underground drilling equipment in 2021 and then moved to synchronous motors, after which there was an expansion in average life from 15 to 22 years and increased ROI of 12%. They cost about 15% more than induction motors at start, but their maintenance cost totals to almost 50% lesser over a period of 5 years.
The cost-saving aspect of the maintenance also shall find practical applications to the peculiar working environment of the mine. In a platinum mine in South Africa, a batch of synchronous motors was under operation at extreme high temperatures (≥50 ° C) and in a very high dust environment, and after 6 months from analysis of operation, found the period of maintenance for this equipment to be extended from 6 months into the familiar 2 years and the consumption of lubricating oil reduced by 57%. This shows that both reduced day-to-day maintenance burdens, and stiff reliable operations within very harsh environmental conditions, are able to provide a very big saving in overall operating costs.
Load fluctuation is stable
Load fluctuations can occur in any kind of mining operation. The most common incidences occur when abrupt shifts of load are thrown on the mining, transportation, and processing equipment engines that need strong load adaptability. One of the main advantages of synchronous motors is their ability to deal with load fluctuations and to keep a good running capacity under these conditions. Synchronous motors are far superior to traditional induction motors and this superiority allows them to reduce the effect of load fluctuations and increase the stability of production processes. In large coal mines, the synchronous motor has decreased downtime by load fluctuation by 40% in the crusher, providing an annual energy saving of around 1,800,000KWH.
On the part of technical parameters, during extreme load fluctuations induction motor is subject to major speed fluctuations thereby causing reduce in efficiency of the equipment. These machines maintain their rated speed even when the load changes and, thereby, absorb load fluctuations. The synchronous motor installation into the mine conveyor system reduces the speed fluctuation error from ±5% to ±1% during load changes; thus, greatly reducing mechanical damage and equipment downtime due to load fluctuations.
In view of the economic indicators, the control of load fluctuations directly affects the life span and maintenance values of the equipment. With the implementation of a synchronous motor in 2022 for its crusher drive, the mining company has reduced maintenance costs by some 12%, having avoided earlier wear on the equipment due to unreliable loads. The enhancement attaching greater importance is the reliability and stability of that equipment has seen the mean time between failure (MTBF) more than double: 500 hours to 1200 hours.
In figurative terms, The inherent load fluctuation control of an average firm faces 6.5% loss due to downtime loss. In comparison, a firm utilizing synchronous motors will usually operate under an annual load fluctuation control limit of 3.5%, resulting in millions of dollars in savings on operating costs. CompanyA has achieved lower power losses by 7% and provides for the equipment maintenance cost by 15% through load fluctuation control using synchronous motors in the year 2021 saving nearly 3 million dollars in one year.
From the technical detail stand, taking into consideration the synchronous motor application, the installation is usually incorporated with a high-precision load monitoring system enabling the motor to automatically adjust the excitation current according to load changes in real time and to maintain a usually stable working state. This was reported as implemented successfully on the part of B Mining Company in 2020, to achieve a 65% reduction in load fluctuation of the motor, minimizing risk of sudden downtimes, hence tremendously improving production continuity and stability.
High power output
Particularly crusher, elevator, and other devices, many require high power output in the mining sector; they need strong power to handle challenging tasks. Synchronous motors are very advantageous in high-power demand situations owing to their high power output capacity. For a steel mine, the replacement of a synchronous motor in its core smelting equipment not only increased power output, but also greatly improved productivity. Three months of use have seen a 12% increase in the production capacity of the equipment as well as a rise of 5000 kW to 6500 kW in output power of a single device.
The heat of the motor rises, simple to cause overheating and failure in the long period of high load operation especially when the load rises; therefore, in the face of high power output, the conventional induction motor will have lower efficiency with load increaseespecially in long term operation of high load run. A synchronous motor operates at high efficiency and stability, and it can preserve constant high power generation. The synchronous motor of a gold mine runs continuously with high load; its efficiency remains above 96%, significantly lower than the traditional motor’s 90% efficiency level; and the power output can be stably maintained below 110% of its rated power so as to suit the greater load demand.
Most mines can maintain high power stability during equipment start and stop by using synchronous motors, as per data on behaviour. After the conversion of a synchronous motor in a coal mine, for instance, the starting power stability of its primary conveyor system has improved by 15 percent and the equipment damage from current impact has decreased. The transformation will lower typical motor replacement and maintenance costs, reduce start-up losses in the power grid, and hence reduce yearly power expenses by around $2. 5 million in 2021.
Economically, high power output has considerable direct advantages in view of financial markers. After replacing the synchronous motor, a major bauxite mining business saw an 18% rise in production efficiency, a 25 percent increase in return on investment, and a 12% decrease in energy usage per unit of outputboth of these contributed to a 25% increase in ROIpower of its crusher rose from 3000 kW to 4000 kW. Furthermore, long-term stability and efficiency improvements in the equipment raised production levels and market competitiveness, while the business lowered its power bill by $2 million.
Data comparison shows that synchronous motors can achieve ±1%, while the power output stability of traditional motors is usually preserved in the range of ±3% according to the industry data. In a test of a major mining company, for instance, the use of synchronous motors decreased the range of power output fluctuation of the gear by 65%, therefore not only improving the line’s continuity but also solving the issue of equipment failure due to erratic power supply.
