Nord Drive Systems – designed by German precision engineers, Getriebebau Nord and assembled locally by BMG – encompass modular drive configurations that ensure optimum performance of mechanical speed control for specific applications in industry, including mixing and agitation solutions for water, wastewater, processing and raw materials management applications.
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BMG’s Nord agitator drive systems – which easily move large masses in agitating and mixing applications – consist of an electric motor, frequency inverter, MAXXDRIVE® gear unit and accessories.
“Nord drive solutions, which meet stringent local and international quality standards, are known for reliability, energy-efficiency, low noise levels, extended service life and reduced maintenance,” says Johan (Os) Stoltz, National Product Specialist for Nord Drive Systems in BMG’s Electromechanical Drives division.
These modular drive systems incorporate advanced drive technology and special design features to meet the precise requirements of every operation. In particular, pumps, mixing and agitating systems are required to meet high demands in environmental technology, to distribute safe drinking water, convey wastewater and circulate activated sludge, for example.
BMG’s Nord agitator drive systems – which easily move large masses in agitating and mixing applications – consist of an electric motor, a frequency inverter, a MAXXDRIVE® gear unit and accessories. Notably, the Nord MAXXDRIVE® series is the only complete industrial gear unit system on the market with a one-piece UNICASE lightweight housing for mixing and agitating processes.
Nord helical and helical bevel gear units – available from BMG in various sizes and speed ratios – offer high operational reliability and protection against leaks through optimum sealing. The robust and rigid design enables the system to cope with excessive loads, while the short total axis spacing results in low bending torques and extended operation times for the entire drive system.
BMG also offers a wide range of attachment options for simple and economic integration into mixing and agitation industry applications. “We supply numerous NORD drive components as explosion-protected ATEX versions, for safe operation in hazardous areas, including Zones 1 and 2 for gas/vapour/mist and zones 21 and 22 for dust,” Stoltz adds.
NORD MAXXDRIVE Industrial Gear Units provide high output torques from 15 to 282 kNm and are perfect for use in heavy duty applications such as agitators, conveyor belt drives, mixers, mills, drums or crushers. They are available as helical gear units or bevel gear units and are constructed with Nord’s UNICASE housing, which was developed to accommodate larger roller bearings to guarantee longer service life.
These compact industrial gear units ensure reliable operation even under extreme conditions and are designed for vertical and horizontal installation to minimise required space.
Another important feature of Nord’s MAXXDRIVE-based agitator drive system is the IEC/NEMA approved SAFOMI Seal-less adapter for agitators, which prevents vibrations during operation. This adapter includes an oil compensation volume, so additional attachments and wearing parts such as an oil tank and drive shaft sealing rings are not necessary. This results in greater operational reliability and reduced maintenance.
“Existing MAXXDRIVE helical gear units with standard IEC/NEMA adapters can also be easily converted for SAFOMI adapters,” notes Stoltz.
Nord drive systems for agitators, pumps and mixers used in water, wastewater and process plants are engineered with a VL heavy-duty spread bearing design, which translates to reinforced bearings and increased bearing spacing. These reinforced and larger output shaft bearings allow the gear unit to absorb high radial and axial bearing loads that occur during the agitating process. Advantages of oversized output bearings include quick assembly, large bore capacities, high radial load capacity and longer service life.
To enhance efficiency, BMG offers an agitator version VL2 bearing with increased bearing spacing and reinforced bearings, as well was a drywell version, VL4, with an additional oil drip plate with leakage or oil sensors. The bearing spacing of VL2 to VL4 versions are increased with output flange attachments, while the gear unit size remains unchanged. Nord also offers the VL6 design that allows the gear unit to be mounted onto the face of the housing.
Coaxial drives are recommended for agitators and mixers that require a double agitator, due to the large size of the tank. Double agitators often consist of agitator blades that rotate in one direction in the middle of the tank, while a scraper blade rotates in the opposite direction. This system is designed to efficiently move material settled around the wall of the tank and return it to the agitation blade.
NORD offers the option of operating two shafts inside each other for coaxial agitators. The inner agitator is driven by the upper gear unit and the outer agitator by the lower unit. The direction of rotation and the speeds of the agitator and scraper can be completely independent of each other.
IE5+ synchronous motors and frequency inverters
NORD IE5+ synchronous motors – with the highest defined efficiency class – enhance the performance of these mixers and agitators and are also ideal for food processing, pump and conveyor applications. Notable features include a compact and hygienic design, high corrosion resistance and easy cleaning.
Because a very high percentage of the total cost of ownership (TCO) of an electric motor is made up of the energy consumed by the motor, these new generation IE5+ motors offer a fast return on investment (ROI). They also offer a constant torque over a much wider speed range, and they are particularly easy to clean, with high corrosion resistance due to their smooth and fan-less motor design.
For even greater system efficiency in agitating and mixing processes, BMG specialists recommend Nord DuoDrive geared motors, which feature the Nord IE5+ motor integrated into a single-stage helical gear unit. With a system efficiency of up to 92%, this wash-down-capable geared motor has one of the highest efficiencies on the market in this power class.
Driven by frequency inverters, these systems also achieve high efficiency in partial load operation. Frequency inverters also bring simple plug-and-play commissioning to the drives for systems such as mixers and agitators, all of which, compared to other drive systems, delivers further significant reductions in the operational and total ownership costs for end users.
Pumping applications
Nord decentralised frequency inverters are also ideally suited for controlling associated pump applications. These units save space in control cabinets, reduce costs for wiring and cables and simplify maintenance, thus increasing the efficiency of entire drive systems.
Actuating pump drives via frequency inverters enable different pump characteristics to be selected, simply by changing the system parameters. Various parameter sets are directly stored in the inverter and pumps can be adapted to different media, flow rates or process requirements.
BMG offers fully matched Nord drive systems that are tailored to the exact requirements of every customer’s application. Modular systems are easy to expand or upgrade, using a minimum of different types and sizes of components. Local assembly by BMG enables prompt delivery of drive systems and the ready availability of spare parts.
BMG plays a pivotal role in supporting the productivity and production targets of industrial, manufacturing, mining and agricultural sectors of economies in all the countries it serves. As Africa's largest distributor, manufacturer and service provider, the company has a reputation for delivering quality engineering consumables and components, including: bearings and seals; power transmission components; drives, motors and controllers; hydraulics, pneumatics and filtration; heavy and light duty materials handling; pumps and valves; lubrication, fasteners and gaskets; and a wide range of specialist maintenance and monitoring tools.