Mitsubishi FR-F800 water industry inverters give better control

Image of new inverter Fr-F800 designed for the water industry

 

Inverter drives in the water industry.

 

As with most industries, water companies are following legislation that encourages operations to be more efficient. An example of this is sewage waste being used to generate energy. When implemented locally. it reduces the energy input of the process.

 

Unsurprisingly, inverters or variable speed drives are also widely used. Inverters reduce electric motor energy consumption, but also offer better control. Processes like aeration, chemical infeed and sewage treatment can be more precisely controlled using inverters on various pumps and motors.

 

Inverter controlled pumps are used to match supply to demand throughout the distribution network. They provide more water at peak times and trim it back as demand drops off. Reducing pressure in the distribution network also plays an important role in reducing losses due to leakage.

 

Another important advantage of inverters is that when running equipment at less than full speed, there is less wear and tear. This leads to reduced service and maintenance requirements, which in the case of remote and hard to access pumping stations can represent a significant cost saving in logistics alone.

 

Water Hammer

The electronic intelligence of an inverter can also be adapted to meet industry specific requirements such as controlling water hammer and ‘deragging’. Water hammer is induced when there is a sudden load change within the distribution network. This can lead to temporary or permanent leakage and even catastrophic failure of pipes.

 

Inverters soft start pumps and other equipment and are able to recognise the repeated pressure fluctuations of water hammer and to smooth them out. This not only reduces maintenance and repair demands but can also extend motor life by reducing stresses in the electrical system.

 

Deragging

Deragging is the water industry term for unjamming the impeller of a pump, which is often caused by a build-up of rags or other fibrous debris in the pipework. The problem is commonplace, even though screens and filters are fitted throughout water plant facilities and the wider distribution network. Clearing a blocked pump is both disruptive and expensive.

 

Inverter makers like Mitsubishi Electric has developed self-deragging drives. Here, the inverter detects an excess increase in pressure and triggers a self-clearing sequence that will consist of increasing power and/or cycling the pump back and forward to dislodge the blockage.

 

Harmonics

large inverters employed in the water industry were known for generating harmonic disruption to the electrical supply, and affecting the local power quality. However, the latest generation of drives has addressed this by incorporating active filter technology that typically reduces distortion down to less than 0.5% Total Harmonic Distortion of Current (THDi).

 

Modern inverter drives like Mitsubishi’s FR-F800 are developed using standard hardware with the addition of many application specific characteristics and features in software. A pump rated inverter for instance will be ‘tuned’ to meet the torque control requirements of a pump. It will also be configurable for single and multi-pump installations and have pump related functions such as automatic level and pressure control, soft starting and deragging algorithms.

 

Modern generations of water industry specific inverter drive are designed for a ten-year operating life, have on-board diagnostics, Ethernet communications. They are efficient across a wide range of duties self optimising and reliable

 

See more Mitsubishi Electic inverter drives at 999 Inverters

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