Reducing energy consumption is a reality for all industries in South Africa, and the WEG W22 IE3 premium efficiency electric motor can rightfully claim to be the most efficient motor that is turning industry in the country.
Available from Zest WEG Group, the WEG W22 IE3 is available in models with a rated capacity up to 1,000 kW and has been engineered specifically to reduce energy consumption optimising on total cost of ownership in numerous applications.
The WEG W22 IE3 product line was engineered using the latest generation computational tools such as structural (finite element method) and fluid flow analysis as well as electric design optimisation software. This resulted in a robust product that offers reduced energy consumption and thermal efficiency as well as a reduction in noise and vibration levels
Fanie Steyn, manager responsible for rotating machines at Zest WEG Group, says that because a chain is only as strong as its weakest link, during design close attention was paid not only to the internal efficiencies of the working motor, but also to the elements constituting the external components of the designed motor.
Focus on the frame/housing
The frame is a fundamental component in the design because, besides constituting the mechanical structure reference, it is the main conduit responsible for the heat dissipation generated inside the electric motor.
“In addition, the frame and the end shields ensure the enclosure of the electric components, protecting them against the environment where the motor is installed,” Steyn says. “The frame design ensures high thermal exchange and high reliability where mechanical strength is essential.” The terminal box is located at the front of the frame thereby increasing the heat dissipation area and providing a uniform air flow over the motor frame.
Reliability of the frame was also deemed important, so careful consideration of construction materials led to the selection of FC-200 cast iron which is produced in WEG’s own facilities. Interestingly, this is the same material that is used in WEG’s explosion-proof motors.
Fan and fan cover
The main function of the fan, when assembled directly on the motor shaft, is to promote the air flow over the frame fins, thus dissipating the heat generated inside the motor.
The function of the fan cover is to protect the fan against external agents and to ensure continuous air flow over the motor fins regardless of the environmental conditions within which the motor is operating. As a natural consequence, when the cooling system is operating to promote heat dissipation, it generates acoustic noise and mechanical losses which can be caused by a combination of the friction of the fan blades through the air and ineffectual design of the fan cover’s shape.
Good ventilation is key to reducing the mechanical losses, particularly for two-pole motors. Due to its high efficiency, an IE3 motor has inherently less demand for heating removal, so the ventilating system can be optimised to reduce mechanical losses and consequently acoustic noise.
WEG’s design on the cooling system on these new motors was conceived using the most advanced simulation software and fluid flow analysis software, resulting in an innovative aerodynamic profile with reductions in both mechanical and acoustic noise.
Terminal box
Because the terminal box is the point of contact between the user and the motor, WEG first carried out a field survey amongst installation and maintenance experts to determine optimal design performance. This research resulted in a new terminal box concept that prioritises the interface with the user, providing easier access and handling of the power and accessory cables and ensuring more reliability and versatility in the motor installation.
The new terminal box allows improved cable housing, ensuring larger contact areas between the cables and the motor terminals and allowing correct tightening torque. The diagonal cut design of the terminal box base and the terminal box cover enables easier access to the electrical connection and gives a better view of the interior of the terminal box during installation procedures.
Using the same WEG exclusive BMC (polyester with 20% fibreglass) die-cast terminal blocks that are used for the terminal blocks of hazardous area motors ensures high electrical insulation resistance and durability. In addition, the accessory cable connections are made with quick coupling connectors.
“With a focus on designing for efficiency, coupled with the ability to understand and implement market needs, WEG W22 IE3 motors are a long-term solution to the ongoing need for energy usage reductions,” Steyn concludes.
