Electric motors with permanent magnets


Direct drive for cooling towers based on the  electric motor  with the regulation of
rotational speed  and control system

Direct drive for coolers with rotational speed control


The new direct drive technology - increases reliability, simplifies maintenance, reduces noise and saves energy.


Baldor Electric can offer a direct-drive motors that have the advantages of high rotational moment and the ability to change the rotational speed, while eliminating the cost and maintenance required for traditional gear drive and belt-fix motors, combining the technology of high specific power of electromotors of AC current with a laminated body and high efficiency of construction of salient pole of the rotor on the permanent magnets, supplemented by coordinated function of rotational speed control. The impeller is directly connected to an electric motor and is controlled by a special control module to ensure optimal speed and efficiency of the cooling tower with reduced noise and energy consumption. The control module enables the possibility of connection with use of the most common protocols communication in heating, ventilation and air conditioning systems.


Direct drive on the basis of a synchronous AC electromotor with permanent magnets reduces maintenance costs.


The structural element of AC synchronous motor with permanent magnets provides the use of a laminated body with fins for providing of the high specific power setting and the size of the flange connection let replace the traditional system of "quadrangular gear- countershaft", used in most towers. Similar technology is offered in standard structural elements, those that already have a high specific power is constructive with the installation on the feet, which can replace a pulley-belt fixes in the presence of additional space for vertical installation.

Proven in the most demanding conditions of industrial applications the use on sea platforms synchronous PM motors of AC is the right solution for working in hot and humid environment inside the cooling towers.

Synchronous PM motors for standard cooling towers of TEAO standard (fully enclosed with air-cooling) are designed to meet the least requirements of the service. Bearing lubricant is required only once a year. The penetration of water along the perimeter of the motor shaft is prevented through the use of insulation technology for bearing Inpro / Seal and dustproof rings. The system of protection against the penetration of moisture in the winding of VPI stator (Vacuum Pressure Impregnation) guarantees a long period of operation of the motor in the most extreme environmental conditions. The holes for condensate disposal help to avoid the moisture inside the motor. There is no more need to replace oil in the gear, the lubricant of the body of support bearing or to replace the belt.


The control system of PM motors Baldor VS1CTD for cooling towers.


Baldor management system includes special features that have been designed exclusively for the cooling towers. Management System embodies our principle of the coordinated operation involving the use of a special control for each synchronous PM motor. The most important operating parameters are implemented in firmware VS1CTD to facilitate the start of the cooling tower, eliminating the need for user to input complicated information to the control unit and pre-start coordination of work of control unit and the PM motor. Given the positioning of the control system VS1CTD at the cooling towers market, a complex working interface has been simplified, which typically can be found in general-purpose management. It gives our systems the additional benefit for our electromotors with rotational speed control and management systems.
In the case of the need to automate and control in the operation of the cooling tower, the control system Baldor allows commutation on multiple network protocols including MODBUS-RTU, MODBUS / TPC, EtherNet / IP, LonWorks, Metasys-N2, BACnet, DeviceNet and protocols PROFIBUS



Shaft Seal


Because of the harsh conditions that are inherent in cooling towers, the output of shaft of a drive motor is protected by a metallic, non-contact, wear-free - durable labyrinth shaft seal, which includes locking steam ring that prevents the penetration of moisture. It is proved that this system safely protects bearings from mud and complies with the specifications requirements of engines IEEE- 841 for difficult conditions of exploitation. It has been successfully used in the cooling tower gear for many years. 



Insulation System


It is always wet in the diffuser of fan installation, so the insulation on the stator winding must be reliable and waterproof. For this purpose the insulation based on original system used in the US Navy was developed. The surface is impregnated with a mixture of epoxy in vacuum under pressure (system VPI). This system is recognized as the best insulation system for use in challenging environments similar to considerate one. Such a system is used in the open engines in the harsh environments of exploitation, such as oil platforms in the North Sea. 





An important issue is the complex system maintenance. Since permanent magnet motor has a low speed (has no a high-speed input), the frequency of its lubrication may be increased up to 2 years. There is no need to inspect this engine for leakage of oil, since it contains no oil.
The variable-frequency drive supplies the minimum current for heating the stator winding to a temperature slightly above the environment temperature to avoid condensation and accumulation of moisture in the motor body frame



Features and advantages of the direct drive for the cooling towers on the basis of the synchronous PM motor


The electric motor with direct drive:


Eliminates the need for gear, an intermediate shaft, block of support bearings and connecting joints.

Essentially simplifies the maintenance of equipment and provides improved reliability

Reduces the impurities in the water by eliminating oil leakage from the gear

Reduces power consumption

Has the improved safety due to fewer rotating elements

 Waterproof motor body frame enables the installation directly in the wet air stream

Eliminates the complex work on coordination of the rotating elements, allow quick installation and reduction of the cost of assembly of the fan installation


Bearings and hermeticity:


Oversized bearings for increased service life of more than 10 to 100 000 hours.

Application of consistent grease to extend the service life

Cope with the axial load from the fan with increased reliability

Proven insulation system Inpro / Seal with set dustproof ring on top

Only one entry point


Rotational speed control:


Designed specifically for use in cooling towers and can be set to the optimum speed of rotation.

Control of permanent magnet motor without use of the position sensor or synchronizer

Possibility of heating with a small current eliminates the need for additional space to accommodate the stator windings heaters

No pre-start settings due to technology "coordinated functioning" of the motor and control system

Possibility of soft start (controlled load)

Energy savings and reduction of the mechanical stress on the system

Improving reliability of the system and increasing of the  service life

Reduction of noise load

Ability to optimize the temperature of the circulating water to optimize the compressor equipment work

Possibility of slowdown by small currents and prevention of the fan rotation from the wind in the off mode.

Ability to bypass the rotational speeds, at which a resonance of the system appears


Communication protocols:


The possibility of using MODBUS-RTU, MODBUS / TPC, EtherNet / IP, LonWorks, Metasys-N2, BACnet, DeviceNet protocol and PROFIBUS.
The ability to implement into existing automation systems





Why the energy efficiency is important?

According to the US Department of Energy report, published in 1998, industrial processes that involve equipment driven by electric motors consume 63% of the total amount of used electricity. Report of 2002 confirms that the companies, which have implemented best practices of the Department of Energy actually have an average of 33% savings by installing energy efficient motors and motors upgrade in existing equipment, including the use of rotational speed control systems. This has positive impact on the environment and on the total cost of production.

The acquisition cost is only a small fraction of total costs


A pie chart on the right shows the common costs over the life cycle of the electric motor with the power of 75 kW, which is operated in continuous mode for the duration exceeding 20 years. Referring to the diagram it can be argued that the initial cost of acquiring are almost insignificant compared to the cost of electricity consumed during operation of the motor.

How the effectiveness of the series Super-E of Baldor production meets industry standards?

The Series of electro motors Super-E of Baldor production offer to the consumers the highest level of overall efficiency from available ones of other manufacturers, which meets or exceeds the most demanding energy efficiency class NEMA Premium.






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