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The Lenze SMV frequency inverter is providing the means for isolated rural communities in the Australian Outback to save water and energy at the same time.

The SMV, supplied through Lenze’s Australian distributor FCR, is at the heart of a pumping system that matches the delivery of water to demand, rather than running the pump at full pressure irrespective of demand, which was the previous default operating mode.

The solution overcomes the problems of operating on a SWER (Single Wire Earth Return) system, which is common in remote areas of Australia and other large countries.

With a SWER mains supply there is only a single supply cable, typically strung on poles above ground.

In this case the supply is 480V AC.

The return path for the power is the earth, or soil, which effectively creates a 480V single-phase supply.

Previously, special pump motors were used to suit the supply adding to the installation costs.

This fixed-speed motor/pump combination would be sized for the maximum flow that is most of the community taps on at once, so every time a single tap is opened, full power was used to maintain pressure.

As the starting currents for the motor can be 200-800 per cent of rated current depending on motor load, this would cause lights to dim and other household appliances to be adversely affected.

The Lenze solution was to use a three-phase SMV frequency inverter connected for single-phase input.

The inverter requires derating as the input rating with single-phase current needs to be about twice the output current.

A standard three-phase motor can be used.

In addition, the soft-starting nature of the drive ends the problem of dimming lights.

However, the biggest benefit is that, by using the inverter’s PID input, the pump can run to match demand by maintaining system pressure.

The pump speed is varied and energy savings above 50 per cent can be achieved.

The first customers for this new pump concept are situated in the regional areas of Northern Victoria and southern New South Wales.

‘In addition to the savings in water usage, the reduction in energy usage is considerable, helping to ensure fast payback for the SMV-based pumping system,’ said Adrian Villanti of FCR.

‘To put these savings in context, we were running a 2.2kW motor in the pump of the latest application.

‘At rated speed the motor uses all the 2.2kW of power.

‘We measured it from the SMV’s power usage parameter.

‘When the motor was running at reduced speed – the speed required to maintain pressure flow requirements were measuring just 0.75kW of power usage,’ he added.

This represents a 65 per cent saving in the power required.

In addition to its water and energy saving benefits, the IP65-rated SMV also saves money on the installation as a secondary control enclosure is not required.

Even though the drive is usually installed in a shed or sheltered from the weather, there is still a need to protect the electronics from moisture, wildlife and other contaminants.

The IP65 rating on the SMV delivers this protection and a polycarbonate casing is supplied for additional long-term reliability, which does not degrade from the UV rays in sunlight.

Consistent operation is assured even if there are major fluctuations in the supply voltage as the SMV accepts inputs between 320V and 528V AC.

The Lenze SMV inverters have a wide voltage tolerance and can provide an energy-saving alternative to direct on-line pump systems.

Installation costs are low and standard motors can be used.

A steady water pressure avoids problems with pulsing and leakage and the amount of energy saved is typically more than 50 per cent, according to Lenze.

With 40 years' experience, Lenze Ltd are specialists in drive and automation equipment for the UK market. Today Lenze employ 60 people and operate with management systems approved to ISO 9001:2008.

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The engineering comes first. With almost 50 per cent of our staff being qualified engineers, the right-sized technical solution to your problem is our goal. Our vision of right sizing means to work with you in order to achieve the optimum solution in terms of cost and performance.

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Our products fit together to make the complete drive and automation system. Lenze products include automation, controllers, servos, inverters and geared motors. Our Techdrives division adds essential drive components such as couplings, actuators and locking bushes to complete your design.  

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Lenze companies are in 29 countries and have sales offices in a further 24. Full product information is available on our website and the international helpline makes it easy to contact us.

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