Drive systems for horizontal mills are widespread in both the cement and mining industries. Based on our experience and product knowledge, we provide the right solutions for each application and your unique circumstances.
We often see ball mills used for clinker grinding, while vertical mills tend to be more common today for raw material comminution. In older cement plants, however, both process steps are equipped with ball mills and their corresponding drive systems.
But many of these gear units have seen better days and might no longer satisfy your needs. We offer upgrades, revamps or complete exchanges of your old drive systems to gear up your cement plant for the future.
Among the different types of horizontal mills used in the mining industry, SAG, AG, rod and ball mills are usually equipped with lateral drives. We offer you a full package of complete drive systems, consisting of girth gears for single or dual drive pinions, main gear units and auxiliary drives. Or you can choose our compact MAAG GEAR LGDX Lateral Gear Unit in single or dual arrangement, depending the power requirements of your mill.
FLSmidth provides sustainable productivity to the global mining and cement industries. We deliver market-leading engineering, equipment and service solutions that enable our customers to improve performance, drive down costs and reduce environmental impact. Our operations span the globe and we are close to 10,200 employees, present in more than 60 countries. In 2020, FLSmidth generated revenue of DKK 16.4 billion. MissionZero is our sustainability ambition towards zero emissions in mining and cement by 2030.
EPM electrolytic starter can be used to start slipring motors from 500 kW to 20,000 kW. It will supply the power necessary to drive the motor by resistance variation. Designed for controlled starting and speed control of large slipring motors in demanding applications, the EPM liquir rotor starters ensure a smooth progressive acceleration of installations such as:
They are widely used in various industries such as mines, quarries, cement plants, water treatment and associated industries. They are also adapted to specific applications such as car fragmentisers, plastic mixers and sugar cane knives.
Several models and options are available according to the starting power required, the inertia of the driven machine and the application. Feel free to contact us and explain us about your requirements (Use the section Necessary information to quote a starter), our staff will quote the suitable starter and the eventual necessary options.
Tank: The tank is manufactured with heavy duty sheet steel 30/10 to 50/10 mm gauge, and is normally supplied complete with lifting eye bolts Tank capacity and dimensions are determined by the motor rating.
The moving electrodes travel vertically inside the insulating container, guided by a nylon rod. The assembly is supported by two brass rods fixed to a transversal carrier which is common to all three electrodes and constitutes the neutral point.
Control and interlocking: Limit switches are incorporated to control the geared motor, and to power the shorting contactor which shorts out the residual resistance at the end of the run up time. The geared motor is fitted with
This type of starter is designed to provide the optimum starting characteristic, which results in smooth progressive acceleration to full load speed. It can also be used for speed variation and torque control. Plug braking can also be implemented with this system.
AOIP starters for slipring motors, also named electrolytic starters or Liquid Resistance Starters (LRS), use mobile electrolytic resistances. Each starter is made of 3 tanks (one per phase) filled with conductive liquid named electrolyte (water mixed with salt, usually Sodium Carbonate) and two immerged electrodes. One is fixed to the bottom of the tank, the other travels vertically inside the insulating container, guided by a nylon rod. The electrodes are in stainless steel (or bronze in option), shaped in concentric cylinders which merge with each other in the minimum resistance position.
The resistance value depends on the distance between the electrodes, Sodium Carbonate concentration, and electrolyte temperature. The level and temperature of the electrolyte are controlled by a float and thermostats triggering an alarm when set limits are reached.
By distance variation between the electrodes, we get an accurate variation of resistance, thus a supply voltage adjustment and a reduction of starting current and torque, purpose of the system. (see Why using a starter for slip ring motors)
The starter slowly decreases the resistance, ensuring a progressive starting of the driven machine, unlike step starting due to starters with fixed electrodes. At the end of the starting process, the resistance is short-circuited.
Some LRS manufacturers do not use mobile electrodes but prefer to vary the level of electrolyte to modify the resistance value. This solution implies using circulation pump which has two disadvantages:
In order to start a slip ring motor, the accelerating torque has to be sufficiently higher than the resisting torque. Higher is the inertia, higher has to be the accelerating torque, otherwise the start will be very long and the motor can be damaged by the heating.
In order to reduce the starting current and starting torque, it is necessary to decrease the supply voltage of the motor. If the supply voltage is divided by two, the absorbed current is divided by the same ratio of two.
For example, for a motor with a ratio starting torque / nominal torque of two and a ratio starting current / nominal current of six under a nominal voltage of 400 V, if the supply voltage is reduced to 200 V the absorbed current is only three times the nominal current. Furthermore, the torque is reduced by the square of the supply voltage reduction, by reducing the supply voltage from 400 V to 200 V, the motor torque is 2/(2x2) ie 0.5 times the nominal torque.
Different models exist to suit the power of the starter(s) and the inertia of the driven machine.The ranges of EPM starters given above are theoretical only, as ranges will depend on many further non negligible parameters such as starting conditions, starting time and cadenza, torque, type and load of the driven machine, ambient temperatureRotor voltage between rings: 3,500 V maxStandard starting times: 20, 30, 40, 60, 80, 130 s factory presetLevel of electrolyte monitored by magnetic floating systemElectrolyte temperature monitored by thermostatsElectrolyte cooling down by natural convection and agitator mixingLow current density of electrodes: about 1 A/cm.
AOIP offers a complete range of services: technical assistance and advice, calibration and verification by the SOFIA laboratory, equipment repair, maintenance, assistance and metrological monitoring, equipment rental, training, installation and commissioning of your equipment. More informations
However, the above two disadvantages can be overcome by installing diesel-driven DC generators and turbine-driven 3-phase alternators which can be used either in the absence of or on the failure of normal electric supply.
Cumulative compound motoris a varying speed motor with high starting torque and is used for driving compressors, variable head centifugal pumps, rotary presses, circular saws, shearing machines, elevators and continuous conveyors etc.
Because its speed remains constant under varying loads, 3-phase synchronous motoris used for driving continuously operating equipment at constant speed such as ammonia and air compressors, motor generator sets, continuous rolling mills, paper and cement industries.
Squirrel cage induction motorisused for low and medium power drives where speed control isnot required as for water pumps, tube wells, lathes, drills, grinders, polishers, wood planers, fans, blowers, laundary washing machines and compressors etc.
Double squirrel cage motoris used for driving loads which require high starting torque such as compressor pumps, reciprocating pumps, large refrigerators, crushers, boring mills, textile machinery, cranes, punches and lathes etc.
Slip ring induction motor is used for those industrial drives which require high starting torque and speed control such as lifts, pumps, winding machines, printing presses, line shafts, elevators and compressors etc.
It possesses high starting torque and its speed can be controlled over a wide range.Single phase series motoris generally used for driving small domestic appliances like refrigerators and vacuumcleaners etc.
It has fairly constant speed and moderately high starting torque. Speed control is not possible. Capacitor-start induction-run motoris generally used for compressors, refrigerators and small portable hoists.
Its operating characteristics are similar to the above motor except that it has better power factor and higher efficiency. Hence, capacitor-start-and-run motorsarecommonly used for drives requiring quiet operations.
This is really informative, and handy when you need to choose a type of electric drive. It would also be really handy to give a rough price comparison of different power options, as the most cost-effective motor that delivers the drive solution is generally sought. eg; generally an SCI motor is used for small appliances, like say, a bench saw. These motors are cheap to produce, but are heavy and not all that efficient. A slightly more efficient motor would be a CS (Cap Start) motor, and an even better option would be a CSCR (Cap Start, Cap Run) motor, which also has a higher start torque. This option may come at a price premium though, so may not be the most appropriate. So for portable equipment, a series shunt motor would be used, because its power to weight ratio is much better.
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Cement plant motor manufacturing is one of our main product focuses. Cement mills, fans, shredders - in the production of cement, particularly large and efficient motors are required for the most diverse processes. MENZEL offers individual motor solutions for all applications in the cement industry up to 13.8 kV and 25 MW.
Thanks to our many years of experience in the manufacturing of cement plant motors, we are the partner of choice for many cement mills operators all over the world. We offer large low-, medium- and high-voltage motors for various industrial sectors. Cement plants represent a particularly exciting challenge here: continuous use, highest performance requirements, high levels of dust, extreme ambient temperatures or installation altitudes. Where heavy masses of raw material are being transported, crushed, grinded and burned, the highest demands are placed on our cement plant motors.
MENZEL cement plant motors guarantee a trouble-free and high-performance operation of your plant. We offer very robust slip ring and squirrel cage motors that are also suited to difficult start-up conditions. Menzel Elektromotoren not only provides electric motors to end users directly, but is also a supplier and partner of drive manufacturers, distributors, and maintenance companies. As a motor manufacturer, we carry a large stock including many unusual motor versions and is highly experienced in customized motor adaptations.Many repeated orders are proof of highest quality and reliability.
Our electric motors delivery program for the cement industry includes three-phase motors with slip ring rotor or squirrel cage rotor up to 13.8kV. Various designs as well as all types of protection and cooling are possible.
Our electric motors for cement mills and other all are manufactured in compliance with the currently valid EN60034 and IEC60034, VDE, DIN and ISO standards and meet all international standards. Menzel Elektromotoren Berlin is TV certified according to DIN EN ISO 9001.
A costly industrial plant such as a cement mill must produce flawlessly at all times. In the event of a plant shutdown, with MENZEL you can count on a manufacturer who can provide you with electric motors at short notice from stock - worldwide. MENZEL keeps one of the largest stocks of major motors for the cement industry across Europe.
We can provide you with large brand new medium and high voltage motors with squirrel cage or slip ring rotor up to 15000 kW directly from stock. We keep motors of our own MENZEL series, but also of other brands in stock and can provide them within a very few days. Special constructions and individual adjustments of our electric motors are possible at any time.
You have an emergency and plant shut down? The best way to make your inquiryis to use our contact form, specifying how fast you need the electric motor you're looking for.One of our engineers will get in touch with you quickly.
Menzel was to supply a spare slip ring motor for a cement plant in Canada and had to meet very exacting requirements. This was the third order of motors that this Canadian system integrator has recently placed at MENZEL. The new slip ring motor must be able to replace three existing crusher motors in case of a failure. To ensure smooth commissioning at the installation site, which is characterized by very tight space restrictions, Menzel's project manager took the measurements in Canada himself.
Menzel chose a 4.5 MW slip ring motor from stock and built an extended shaft. Furthermore we fitted special adapter plates with mounting holes for all three locations as well as brackets for plug and play mounting of vibration sensors for condition monitoring. The custom-made adapter plates were made in our in-house welding shop, which allows flexible production of special components and custom-made welded designs at all times. In addition, the terminal box of this spare slip ring motor was fitted with long feeder cables to facilitate the third-party connecting-up.
Through our many years of experience in the manufacturing of cement mill motors, we are familiar with a wide variety of requirements and can advise customers from the industrial cement sector around the world. MENZEL electric motors are being operated in numerous industrial plants, not only cement plants. Further reference projects from the industrial cement sector and others can be found here.
Menzel offers a comprehensive range of larger electric motors for the industrial cement sector. As a manufacturer of electric motors, we place our customers and their individual requirements at the heart of the focus of our engineering work. Our service packages covers far more than just delivering the correct drive. We also offer a wide range of services including support, maintenance, commissioning, consultancy, and logistics. We follow a clear objective, which is to be available to our clients at all times:
Explanation: The term MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor. It is one of the most common transistors in digital electronics. It is a majority charge carrier device with the fastest switching because it does not have minority charge carriers which take more time in settling down.
Explanation: Snubber circuit refers to a kind of DV/dt protection circuit of the thyristor. It is used to limit the high rate of change of voltage from cathode to anode. It is usually used to protect SCR thyristor from high DV/dt and di/dt stress.
9) A 1 - full-wave rectifier is made by using thyristors. If the peak value of the sinusoidal input voltage is Vm and the value of the delay angle is ?/4 radian, find the average value of output voltage
Explanation: TRIAC is an abbreviation for a three-terminal ac switch. If we divide TRIAC, we get TRI ana AC. "TRI," as the name suggests that the device consists of three terminals, and "AC" means that the device controls the alternating current. It is a four-layer, 3 terminal bidirectional device.
12) A solar cell of 450 V supplies power to an ac source of 440 V, 50 Hz through a 3 phase fully controlled bridge converter. An inductance with a value of 10 A is connected to the dc circuit to maintain the dc current. If the resistance of the solar cell is 1 , each thyristor will be reverse biased for a period of
Explanation: Most suitable power device for higher frequency (above 100 kHz) switching application is power MOSFET because it has lower switching losses. So, for lower frequency switching applications, BJT is used.
Explanation: IGBT stands for Insulated Gate Bipolar Transistor. It includes the best features of power MOSFETS and power transistors(BJT). Same as a MOSFET, it has low input capacitance and high input impedance. In one state, it has low resistance and high current controlling capacity like a BJT.
Explanation: The thyristor is known as SCR because it is a silicon device used as a rectifier and that rectification can be controlled. It is made up of silicon only because the leakage current in silicon is less than that of germanium. If any device is used as a switch, it is necessary that leakage current must be minimum.
17) A single-phase controlled, a full-bridge converter is supplying a highly inductive DC load. The conductor is fed from a 220 V, 50Hz, ac source. Find the fundamental frequency in Hz of the voltage ripple on the dc side
18) A single-phase fully controlled thyristor bridge ac dc converter is operating at a firing angle is 300 and overlap angle is 200 constant dc output current of 10 A. find the fundamental power factor at input ac mains?
Explanation: Freewheeling diode is also called bypass diode or commutating diode. It is used to improve the waveform of the loaded current and power factor. It is connected across a realy, which is driven by a transistor. It enables for dissipation of energy stored in the inductance of the load in the circuit and provides a continuous flow of load current when the thyristor is blocked.
26) A 3 phase, 6 pulse SCR converter is connected to a voltage source of 220 V, 50 Hz, AC mains, and controlling a dc drive with terminal voltage 210 V and rated current value is 90 A. If the commutation angle = 150 and firing angle = 60,0, find the rating of shunt compensator and power factor.
Explanation: Buck-boost regulator provides output voltage polarity reversal without a transformer. The buck-boost converter refers to a voltage regulator used to regulate dc power supplies. A negative polarity output may be required with respect to the same terminal of the input voltage. The output voltage can be either more or less than the input voltage.
Explanation: Choppers refer to a static switch used to provide Variable DC voltage from a constant DC voltage source. It is a DC to DC converters. It can be either step up or step down DC to DC converter. In Step up DC converter, the output voltage is less than the input voltage. It is also known as Buck converter. In step-up, DC converter, which is also called Boost Converter, is opposite to buck converter. There is also a converter based on the combination of these two; it works in both buck and boost mode depending upon operating conditions; this type of chopper is called Buck-Boost Converter.
Explanation: A cycloconverter is a kind of AC to AC converter based on thyristors that converts AC at one frequency to ac of another frequency without the involvement of a dc source. It is used primarily to increase or decrease the frequency of the output voltage(s) with respect to the frequency of the input voltage(s), without using any AC-DC nor DC-AC converters during the process. The supply side of the cycloconverter is considered as the input, while the load side is considered the output of it.
Explanation: 18 switches are required to construct a three-phase to three-phase cycloconverter. Three phases of a three-phase cycloconverter need three sets of three-phase half-wave circuits, and each circuit needs 6 thyristors. So the total number of thyristors required is 18.
35) A three-phase cycloconverter is used to find the variable frequency single-phase ac output. If the single-phase ac load is 240 V, 50 A at a power factor of 0.8 lagging, find the RMS value of input voltage per phase
Explanation: PWM stands for Pulse Width Modulation. It is used in the voltage source inverter to control the output voltage and output harmonics. It is a method of controlling the average power of a signal over a continuous range by switching it between on and off states. It is a method of generating amplitude modulation. By increasing the number of pulses per half cycle, the order of harmonic frequency increases so that the filter's size is reduced.
38) A single-phase full-bridge voltage source inverter (VSI) is fed from a 240 V dc source. If a pulse of 600 duration is used to trigger the devices in each half-cycle, find the RMS value of the fundamental component of the output voltage.
39) An electric motor, developing a starting torque of 18 Nm, starts with a load toque of 9 Nm on its shaft. If the acceleration at the initial point is 3 rad/sec2, find the moment of inertia of the system(Ignore friction)
41) A 240 V, 1200 rpm. 30 A separately excited dc motor has an armature resistance of 3 ohms. A step-down chopper controls the dc motor with a frequency of 1 kHz. The input dc voltage given to the chopper is 280 V. If the duty cycle of the chopper for the motor to operate at a speed of 700 rpm, find the rated toque
42) A single-phase half-controlled rectifier is driving a separately excited dc motor. The back emf constant of the motor is 0.30 V/rpm. The armature current's value is 8 A without any ripple, and the armature resistance is 3 ohm. The converter is working from a 240 V power supply of a single phase ac source with a firing angle of 600. Find the speed of the dc motor under this condition
Explanation: Ripple frequency refers to a frequency of the residual AC voltage. After that, it has been rectified to DC in a power supply. Because of higher ripple content in the converter output motor, heating and commutating problems arise. It works on high DC voltage. For a half-wave rectifier, the value of ripple frequency i the same as the AC frequency, and for a full-wave, the value of ripple frequency is twice the original AC frequency.
Explanation: Single-phase induction motors work on single-phase AC supply. It has two windings; Main windings and auxiliary winding. For speed control of a single-phase induction motor by an ac voltage controller, and only a fundamental component of current is required to develop a toque. The harmonics in the motor current may cause power losses resulting in heating of the motor.
46) A resistance of 4 ohms is connected in the rotor circuit, and a resistance of 8 ohms is additionally connected during OFF periods of a chopper. The OFF period of the chopper is 6 ms. Find the average resistance in the rotor circuit for the chopper frequency off 200 Hz.
48) A 3- fully controlled thyristor bridge converter is used as a line commutated inverter to feed 60 kW With the power 450 V dc to a three-phase, 430 V (line), 50 Hz ac mains. If the dc-link current is constant, find the RMS current of the thyristor.
Explanation: Cycloconverters are mainly used where precise speed control is needed. It means cycloconverter is not suitable for cement mill drive as well as compressor drive. Papermill requires constant speed drive. So cycloconverter fed induction motor drive is widely used for machine tool drive.
51) A dc chopper is used in the regenerative braking mode of a dc series motor. The dc supply is 400 V, and the duty cycle is 60%. The average value of armature current is 80 A. If it is considered as continuous and ripply free, find the value of power feedback to the supply?
Explanation: A power diode refers to a semiconductor device that is used to convert alternating current to direct current. It consists of two terminals, cathode and anode, the same as that of a normal diode. A power diode is nothing but a signal diode with an extra layer.
Explanation: PN junction diode refers to a diode that is formed when a p-type semiconductor is fused with an n-type semiconductor. It creates a potential barrier across the diode junction. In forward biasing conditions, the PN junction diode acts as a closed switch.
Explanation: The two-transistor models of an SCR are obtained by bisecting the SCRs top and bottom two layers. SCR is a unidirectional device that works like a diode. It enables current to flow in a single direction only.
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Throughout the cement production plant, hundreds of drive systems of all sizes perform indispensable tasks. They serve as the interface between your electrical and mechanical components and they often come from multiple vendors. Our cement process expertise and engineering help you address all your drive requirements with a coordinated portfolio: the SICEMENT Drives. With the right drive solution in the right place, we can leverage your potentials for increased reliability, productivity, and energy efficiency always with your entire process chain in mind.
The SICEMENT Drives includes specific drive solutions for all normal cement production processes. Despite the wide power spectrum, standardization allows them to be completely incorporated into an integrated power supply network and control system. This is vital to guarantee safe and transparent operation of processes throughout the cement works.
SICEMENT Drives offer the worlds first true one-stop solution for entire drive systems frequency converters, motors, couplings and gear units from a single source. All of these components are perfectly integrated and interact smoothly.
SICEMENT Drives seamlessly integrate any automation environment, and throughout the entire lifecycle. This leads to reduced time to market and time to profit. And you can also leverage the full productivity potential of a harmonized technology landscape, increase energy efficiency, and enjoy reliable system performance in a variety of automation environments.
With modular drive systems, you can flexibly respond to any demand in vertical and ball mills. Our MultipleDrive concept allows you to choose the number and size of components that precisely match the power requirement of your application.
Further advantages of the MultipleDrive concept are the outstanding availability and reliability through continuous condition monitoring and the ability of the mill to keep running even if one of the drives requires maintenance.
A system design incorporating SICEMENT Drives gives you the best output and power utilization. Because we offer such a large selection, you can choose the optimum drive to fulfil each particular mechanical task. Our design ensures potential for major savings in many areas of application.
For example: Speed-controlled drives reduce mechanical impact load because of their soft start feature. Frequency converters with feedback capability put power back into the grid during breaks. And variable-speed drives help you save up to 70% of fans electricity consumption and this typically pays off in just 9 to 24 months.
At the same time, the digitally supported drive technology opens up a new dimension in transparency: the enormous data volumes of the motors and converters can be recorded, evaluated and converted into valuable data. Their analysis provides new insights that optimize the processes, evaluate the condition of the machines and optimally plan the maintenance work.
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Our automatic production line for the grinding cylpebs is the unique. With stable quality, high production efficiency, high hardness, wear-resistant, the volumetric hardness of the grinding cylpebs is between 60-63HRC,the breakage is less than 0.5%. The organization of the grinding cylpebs is compact, the hardness is constant from the inner to the surface. Now has extensively used in the cement industry, the wear rate is about 30g-60g per Ton cement.
Grinding Cylpebs are made from low-alloy chilled cast iron. The molten metal leaves the furnace at approximately 1500 C and is transferred to a continuous casting machine where the selected size Cylpebs are created; by changing the moulds the full range of cylindrical media can be manufactured via one simple process. The Cylpebs are demoulded while still red hot and placed in a cooling section for several hours to relieve internal stress. Solidification takes place in seconds and is formed from the external surface inward to the centre of the media. It has been claimed that this manufacturing process contributes to the cost effectiveness of the media, by being more efficient and requiring less energy than the conventional forging method.
Because of their cylindrical geometry, Cylpebs have greater surface area and higher bulk density compared with balls of similar mass and size. Cylpebs of equal diameter and length have 14.5% greater surface area than balls of the same mass, and 9% higher bulk density than steel balls, or 12% higher than cast balls. As a result, for a given charge volume, about 25% more grinding media surface area is available for size reduction when charged with Cylpebs, but the mill would also draw more power.Get in Touch with Mechanic