With 19 million units sold worldwide, Mitsubishi Electric’s range of frequency inverters sets new standards in performance and energy saving capability.
The portfolio encompasses the FR-D700 micro-drive used for simple applications in the lower power range; the compact general purpose FR-E700; the energy saving FR-F700, which has been specifically designed for fan and pump applications; and the high-end FR-A700 units for advanced applications.
The ultra-compact D700
Despite its ultra-compact dimensions, the D700 has a wealth of advanced functions. It has an improved performance yield in the low-speed range, with vector control and a high overload capacity of 200% at 1 Hz. It has a safety stop built in as standard and is very easy to operate, using simple network connections. With a power range up to 7,5 kW and an output frequency up to 400 Hz, it is ideal for simple drive applications where space is limited, for example pumps, fans, presses, conveyor belts, industrial washing machines and automatic shelf systems.
Best vector control in a compact drive
Another compact drive solution is the E700 range, which has as its main feature exceptional vector control at low speeds. These inverters are very flexible – optional cards can be added and there are changeable I/O boards – and they have lifetime detection on all components. The E700 is an economical and highly versatile solution for a wide range of drive applications including textile machines, door and gate actuators, elevators, cranes, material handling systems and medical apparatus.
The high end A700
The high end A700 drives are suited to demanding drive tasks requiring high torque combined with excellent frequency precision. They offer a combination of innovative functions and reliable technology with maximum power, economy and flexibility. Equipped with Mitsubishi’s innovative real senseless vector control technology, these drives can control the speed and torque of a single phase AC motor without an encoder, with positioning achieved in conjunction with closed loop vector control. The result is maximum performance across the full speed range in terms of dynamic response, precision and control. With a high overload capacity of 250% at 1 Hz, they have integrated PLC control and are very flexible. The A700 drives are ideal for high performance OEM machines where speed and precision are important, as well as conveyors, chemical machines, winder machines, printing machines, cranes and lifting gear, extruders, centrifuges and machine tools.
Energy efficient fan and pump control
The frequency inverters of the F700 series were specifically designed for the needs of energy intensive pump and fan applications, where the potential for power saving is greatest. They can radically reduce power consumption compared to conventional solutions, particularly in the low speed range and the braking and acceleration phases. For example at a frequency of 35 Hz these inverters can achieve a saving of 57%.
With a wide power range of 0,75 to 630 kW and an output frequency range of 0,5 to 400 Hz, they are perfect for air conditioning systems, fans, blowers, hydraulic systems, compressors, sewage, drains, ground water pumps, heat pumps and drive systems with high idling rates.
“These energy saving drives can be used for simple applications yet they are so advanced that they have the ability to match the speed of the motor thus making it possible to run at maximum efficiency says Rowan Krebs, product manager for variable speed drives, Adroit Technologies. The built-in PLC means that functionality can be controlled within the drive. According to Krebs, the F700 series has taken the market by storm, with annual turnover totalling more than €6,5 million after just four years.
Unique features
The F700 range has three unique features: an energy saving mode which can save up to 10% in energy consumption when activated, 5-point V/F control, and optimum excitation control (OEC). In energy saving mode, when the output frequency becomes constant, the inverter has the ability to lower the voltage to a point where it meets the required current, and this is all done automatically. The integrated 5-point curve enables the user to match the torque curve perfectly to the characteristics of the drive system; and with Mitsubishi’s OEC technology, optimum flux is applied to the motor at all times so that maximum drive efficiency is combined with minimum power consumption, adding an additional 12% to the energy saving capability.
In the event of a power failure the inverters will control the stop and initiate an auto-restart. The integrated one-touch digital dial gives fast access to all important parameters. The combination of intelligent design features and specially developed components has increased the service life to an exceptional 10 years, with a warning being displayed when the end of the service life is approaching. The E700 inverters have a full range of communication options, while the built-in control panel allows quick setting, monitoring and diagnostics.
In addition, DC chokes are available for all 700 series inverters from 0,4 to 630 kW to improve the frequency factor of the inverter. These have a number of advantages. They improve the THDi, smooth the DC current, decrease the input current, improve the lambda value and decrease energy consumption by up to 50%.
“Fans and pumps are typically designed with 10% surplus requirements and motors are often oversized for the application; but if the speed can be reduced by 5 Hz, it is possible to achieve a 20% energy saving,” concludes Krebs.
For more information contact Tessa Lithgow, Adroit Technologies, +27 (0)11 658 8100, [email protected], www.adroit.co.za
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