impeller.net The Online Pump Magazine

03.12.2001

Drive keeps motor working at maximum efficiency

Mitsubishi's new F500 series is a development of the highly successful A540 drive and uses Flux Optimisation technology to ensure the motor is working at its maximum efficiency the whole time

The part that inverter drives can play in saving energy with pumps and fans has been understood for a long time and many people have benefited from using them to control the speeds of variable torque loads over the years.
With the advent of the Climate Change Levy in April of this year, there has been a big intensification of interest in this field as power users struggle to keep a competitive edge in the face of escalating electricity bills.
In launching a new inverter dedicated to energy saving, Mitsubishi have now taken a typically innovative approach which greatly increases the scope for getting energy even more under control.
The new F500 series is a development of the highly successful A540 drive, with which it is fully compatible.
Whereas the A540 was designed to maximise dynamic performance to meet the heaviest of demands, F500 uses an adaptation of the same technology - called 'Flux Optimisation' - to calculate and control the voltage applied to the motor.
This means that the motor is working at its maximum efficiency the whole time, and so using the least power.
Perfect for the advanced and intelligent control of pump and fan loads, Flux Optimisation works equally well with any lightly loaded motor.
This means the possibilities for saving energy are not confined simply to pump and fan loads which do not depend on running below maximum speed, but any lightly loaded motor could be a candidate.
Apart from extreme flexibility in motor control applications, the new Drives have all the latest energy saving features a user will ever need.
At low loads they are up to 16% more energy efficient than previous comparable products.
The highly flexible F500 series have been built and designed to be future proofed against any new levy changes and are available in frame sizes from 15kW to an impressive 375kW.
The large power range of these Drives is more than enough for most motor control applications and is perfect for centrifugal pumps and fans and other lightly loaded motors.
Physical design is also important in the new Drives and the chassis frame size is the most compact in its class, making it ideal to fit in small areas.
This reduces cabinet enclosure costs and allows for even smaller overall machine design, while opening up opportunities for simple re-fits in locations previously thought unworkable.
If users need any extra equipment they need not look any further, as the F500 has a comprehensive range of 12 pulse, 24 pulse and zero harmonic options.
Furthermore when its used with a Mitsubishi DC Link choke, the Power Factor on the Drive improves to 95%.
The F500 is designed to be compatible with many of the existing popular A540 accessories.
This means users can maximise their investment in their existing Drive support assets.
A new CPU is included in the Drive, giving it the fastest processing performance of any of the current Mitsubishi range.
This new processor has built in PID control for simple loop operations when connected to an encoder reducing then need for expensive dedicated loop control equipment.
Other benefits, such as an intelligent self-learning feature that allows the Drive to tune itself to suit the application are all resulting from the new CPU design.
A new motor sequencing function is another important feature.
When running in PID control, the inverter drive is able to control the switching of multiple motors (up to 4), so that they are either inverter controlled or switched direct on line, depending on the load/speed requirement.
This can also rotate the duty and standby motors automatically.
Taken together with a whole host of benefits to make the users life easier - like the self-commissioning function to find the best acceleration and deceleration times, the compatibility with Mitsubishi's MX500 simple programming software or the full fieldbus capabilities, there has never been a more cost-effective way to save money on motor control.
Reliability is an area where Mitsubishi's reputation is second to none.
This was pointedly made clear in a recent European market survey by the independent research company IMS.
They concluded that customers found Mitsubishi Electric's Drive products to be the most reliable.
To demonstrate this at a product design and engineering level you only have to consider the use of smart cooling fans that switch on only when required, extending the life of the Drive considerably by closely regulating its operating temperature.
Networking options are now a pre-requisite in any control equipment.
Therefore the complete range can be connected to all the major open fieldbuses, such as CC-Link, Profibus DP and DeviceNet to name a few.
If these are not enough, the F500 series has a range of other communication modules, including RS485 which allows the Drive to be connected to programming and supervisory software, such as MX500 and MX SCADA.

Mitsubishi Electric

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