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Traction elevators are one of the most commonly used types of elevators. They use a rope and pulley system to raise and lower the elevator cab. The weight of their cab is balanced by using a counterweight, which was first introduced in 1900. Nowadays, some elevators are using steel belts in place of steel ropes. … Continue reading "Geared vs. …
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next size Gearless Mill Drive, i.e. a 42ft mill. It is a dual design approach considering, on the one hand, the experi-ences Siemens made with Gearless Mill Drive (GMD) instal-lations over the past 40 years and, on the other hand, using computerized design tools calculating the system behavior where experience does not yet exist.
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The comparison of a conventional drive train to a gearless drive for a grinding mill is shown in figure 1. Figure 1 – Top view of SAG mills with alternative drive options; left side: dual pinion drive including motor, gearbox, pinion and girth gear;
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Table 1 — Mill comparison capital cost Project Mill size DXL (ft) Drive system Capital cost Horsepower Production rate A Ptimary SAG, 26x11 Vatiable speed ac synchronized motor mill, $1.3 million 4025 11,000 coupled to a gear dfive. motor, $1.3 million Secondary ball mill, 18x27 ac synchronized motor coupled to a gear mill, $1.6 million
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Eliminating such components significantly increases the efficiency and the availability of the mill. The gearless motor is fed by a cyclo-converter which lets the operator easily vary the mill's operational speed. ABB (then BBC: Brown Boveri & Cie) installed the world's first Gearless Mill Drive (GMD) in 1969.
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Fig. 1, General scheme of a Gearless Mill Motor drive [24]. of the airgap is in the range of 15-17 mm. A tolerance of +/- 3 mm is consi dered for setting alarm s and protections.
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The SIMINE Gearless mill drives pump system significantly enhances concentrator productivity by eliminating the reducer gear between motor and pump and all corresponding maintenance. In addition, the cyclone pumps with variable speed can adjust their energy consumption to the optimized flow of pulp, resulting in energy savings of up to 30%. …
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czech large sag and ball mill drive systems czech large sag and ball mill drive systems. Gearless mill drives Grinding ABB . ABB's GMD is the most powerful mill drive system in the market to power semiautogenous (SAG), ball and autogenous (AG) mills, This 'workhorse' for grinding operations combines a robust, service-friendly and fit for purpose design to provide …
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SIMINE Gearless mill drives – outstanding reliability for your mine The gearless concept The gearless drive avoids any contact between the rotating mill and the static parts of the motor. This allows for contin-uous workflow without maintenance on the gears or the pinions. What used to be downtime is now productive time.
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Ringmotor of the Gearless Mill Drive (GMD) System. CYCLOCONVERTER Principle The Cycloconverter is a frequency changer which converts a poly-phase voltage with the frequency f1 into a single or poly-phase voltage with a different, lower frequency f2. On Gearless Mill Drives (GMD), the operational output frequency varies from 0.3 Hz up to about 6 Hz.
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The gearless drives system in comparison uses only two (2) drive pulleys, each with a 3,800 kW rating. Hence only two cycloconverters and two medium-voltage switchgears were needed as opposed to the original four VFD's and four medium-voltage switchgears. By reducing the electrical equipment, the E-house footprint was half of the original size.
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Gearless mill drive system in iron ore processing. ABB was recently contracted to supply gearless mill drive (GMD) systems for two 38 foot semiautogenous grinding (SAG) mills at the Serra Azul iron ore mine in Brazil. The Serra Azul mine unit, owned by MMX Mineração e Metálicos, an EBX Group company, is located in the iron quadrangle of ...
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A cycloconverter-fed gearless mill drive is a drive system that has hardware and software protection functions to protect the equipment in case of abnormal operating conditions, malfunctions or ...
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1 – Ring Motor and Mill Complexities. We have been fortunate to undertake detailed mechanical and structural design reviews and audits of all mill types from the five major mill vendors and of ring motors from both the gearless drive vendors. We have also been hired by mine owners to determine the causes of most of the major modern mill and ...
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Although GMDs have been in service for decades, and are known for their operational efficiency (reliability and robustness with reduced operating cost per ton), compared to conventional drives, in the last decade due to certain reasons some failures led to serious unscheduled shutdowns and significant insurance events.
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The poles of the gearless or synchronous motor (also called wrap-around motor or ring motor) are directly installed on the pole flange of the mill shell, turning the mill body into the rotor. The stator is then wrapped around the mill. The gearless motor is fed by a cycloconverter which has a rated output frequency of around 5 Hz for the GMD drive.
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Comparison of AGMA standards for spur/helical gears ... Concrete madness - foundations of SAG Mill gearless drive A gearless drive will require about 250% more concrete and more importantly more reinforcing steel in the foundations than the equivalent dual pinion drive = $$$$$ This picture shows only what is above the ground.
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Mill Drive Developments . The economic evaluation of large multi-pinion and ring motor drive systems has led to a ... A comparison of the rotor drive with gearless and CCV twin pinion system, on a cost and timing basis, was recently provided by Morgan (2001) – Table 2.
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Direct-drive has more potential for further improvement. Experts argue the gearbox wind turbine is almost at its maximum efficiency point, while the direct-drive turbines have more possibilities for improvement. 3. Direct drive is more efficient for future higher power rating wind because the gearbox wind turbines require extra stages of gears ...
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125+ Gearless mill drives systems 720+ Km of belt conveyor system ... MineOptimize – Gearless Conveyor Drive for medium power Comparison of motor types June 24, 2019 Slide 21 PM Sync Power 1500KW 1500kW ... - With a little lower weight the …
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Minerals Industries, Inc. 240 Arch Street, P.O. Box 15312 York, Pennsylvania, USA 17405-7312 Phone: + 1 717 843 8671 Fax: +1 717 845 5154 E-mail: mineralsprocessing.info@ Gearless Autogenous/ Semi-Autogenous Mills. Open the catalog to page 1. The sights and sounds of large grinding mills in operation are ...
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Figure 4: Gearless Mill Drive (GMD), courtesy of ABB Figure 4 shows a typical gearless mill drive (GMD) featuring so called ring motor (introduced in 1969 by ABB): the rotor poles are fixed directly to the mill shell and the stator is wrapped around it.
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conventional mill drive system, such as ring gear, pinion, gearbox, coupling or air clutch, motor shaft and motor bearings. Eliminating such components significantly increases the efficiency and the availability of the mill. The gearless motor is fed by a cyclo-converter which lets the operator easily vary the mill's operating speed.
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Gearless mill drive training. ABB is number one in gearless mill drives (GMD) and combines its extensive industry knowledge with its application experience to select the most economical drive solution for your particular circumstances. The wrap around motor is designed with so-called Roebel bars for the stator winding, which have a positive ...
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Siemens, the company that introduced Gearless Mill Drives (GMD) to mining industry started up its first GMD on a ball mill in Norway in 1980. The mill and its drive system are still in service. Today, GMDs are mainly used for SAG mills between 36 and 40 feet (10.7 to 12.2 m) and ball mills from 24 to 28 feet (7.3 to 8.5 m).
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Direct-drive solutions, can provide the highest level of accuracy, precision, and torsional stiffness on the market. Another key improvement is …
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Ringgeared mill drives (RMD): a system used to drive (rotate) a mill. The RMD itself is comprised of motor(s) (synchronous or asynchronous), a frequency converter, transformers and control equipment. As opposed to gearless mill drives, the motor in RMD is mechanically connected to the mill via a coupling, pinion(s) and ringgear.
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A detailed animation showing the workings of a Gearless Mill Drive (GMD), created from a series of CAD files and in-situ photographs.
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The first gearless mill drive was introduced by ABB in 1969 (then Brown Boveri & Cie) and installed at France's Ciments Lambert-Lafarge in Le Havre, . A picture of a gearless mill drive can be seen in Fig. 1a and b and an exploded view can be seen in Fig. 1c, which in most aspect is similar to the one being analyzed. A gearless mill drive ...
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For gearless drives, motor torque output at the maximum desired operating mill speed and ball charge volume has to be determined. Primary Mills: Torque Output (by Motor) vs Torque Demand (by Mill) For the purposes of this discussion, "drive speed" refers to the output speed of any mill drive system, whereas that of
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