Drives with LON chosen for Finnish HVAC contract

The FR-F700 series of power-saving inverter drives can produce savings of up to 57% compared with conventional drives.

When the Finnish city of Tampere undertook a major renovation of one of its key buildings, only one model of drive was considered for fan control in the heating and ventilating system - the highly efficient FR-F700 inverter drive from Mitsubishi Electric - one of the few drives in the world with LON communications.

Whilst the FR-F700 series of power-saving inverter drives can produce savings of up to 57% compared with conventional drives, this was not the motivation for its selection in this HVAC contract.

Jyrki Viitakoski of UTU Power Electronics, Mitsubishi's local distributor explains.

"The Tampere local authority has standardised on the LONWORKS platform for the harmonisation of key building systems - security, lighting and so on - and wanted to integrate the HVAC system, right down to individual drive level," he says.

"Now, using FR-F700 with LON, there is central monitoring of all key parameters, with plenty of advance warning of any problems, improving the quality and reliability of air handling in the building".

The NEKALA 2 building, built originally in 1968, comprises some 15,000 sq m over two floors, with an internal volume of 25,0000 cu metres.

Housing some 80 people, responsible for various local authority functions, the building incorporates a depot, with garages as well as offices, a kitchen and lunchroom and, of course a sauna.

The project involved the conversion of workshops to provide additional office space, involving a revamp of the HVAC system as well as building and fitting out of the new space.

The upgrade of the HVAC system was undertaken by contractor Tampereen Ilmastointiyhtyma Oy, with other automation work carried out by TAC Finland Oy.All other electrical work, including the installation of the three F740 drives and motors (one at 2.2 kW, two at 1.5 kW), was carried out by Tampere 's own electrical contracting department.

Using the LONWORKS network, the drives, running in speed control, receive run and speed command from the TAC PLC controller, and feed back comprehensive data - speed, current, alarms and other data.

The FR-F700 features both optimum excitation control, for improved motor efficiency during constant speed operation and acceleration periods, and optimum torque patterns which accurately match the power delivered to that required at any instant.

The speed of optimisation is effectively instant, so the drive is always giving maximum performance and efficiency to the load; previous generations of technology could only effectively optimise for energy efficiency under steady load or speed conditions.

Its ease of commissioning, its removable terminal block, on-board EMC filter, predictive maintenance monitor and its tripless reliability, as well as its ability to optimize energy usage, have made the FR-F700 a very popular choice for pump and fan drive applications.

With its LON connectivity, the drive can be simply added to existing networks, such as at this Tampere local authority building, integrating into the single smart building system.

LONWORKS allows the integration of key building sub-systems from multiple manufacturers, simplifying total building control and monitoring.

As new areas of a building are upgraded, or entire new buildings are added to a complex, users are free to pick products and services from any vendor they choose without fear of being locked into one supplier.

Devices within this Tampere building all communicate across a single LONWORKS network, which was in place prior to this current upgrade.

"The city of Tampere uses a lot of Mitsubishi drives," concludes Jyrki Viitakoski," and they were delighted that these latest drives could be integrated into the LON network - it was a key reason for their selection".

"It means that data from the drives can be used directly to determine maintenance needs and intervals, making it much more efficient for the client.".

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