Drives hold air temperature constant for painting

Three large chiller units, featuring FKI high power drives, ensure air temperature in Jaguar's paint plant is kept constant.

Jaguar cars are impressive not only for their distinctive looks, but also for the standard of their paint finish.

The company has invested large sums into its paint preparation plant to achieve this result.

A major part of this investment has been directed into three large chiller units supplied by Carrier Engineering.

Employing high power FID 3000 drives from FKI, these units ensure that the air temperature in the paint plant is kept constant during the critical summer months.

High levels of production flexibility and environmental conformity are the order of the day at Jaguar Cars.

Cars are built to customer order in a highly automated process that enables the colour of the vehicle to be changed, at will, from one car to the next.

This is possible because the time interval between two cars is sufficient to clean the spray equipment of the water based paint, ready for another colour.

The colours of the cars may vary but the conditions under which they are prepared do not.

A general requirement is that air temperature must be held constant if perfect consistency of paint application, adhesion and curing is to be achieved.

Maintaining these parameters within the summer months is most difficult to achieve and requires special equipment.

This task was performed by large chiller units using refrigerant pumps with adjustable impellers, which altered the refrigerant flow to control the cooling rate of the system and, hence, the air temperature.

The system worked reliably, but was not efficient because the pump motors were always driven at a constant speed irrespective of the impeller position.

There were also environmental considerations for Jaguar, who were keen to change from non-ozone friendly gas (CFC) to ozone friendly refrigerants at this site.

However, as the refrigerant turns from liquid to gas, the ozone friendly mediums are not as efficient in ensuring the same levels of heat transfer.

As a result, the pumps would need to be driven faster to achieve the same level of refrigeration using the new ozone friendly medium.

Three large chiller units from Carrier, one of the largest suppliers of such systems in the world, were modified to incorporate FID 3000 drives from FKI, bringing the improved energy efficiency and enhanced levels of control required at Jaguar's paint plant.

The drives are used to control the pumps in the chillers, matching pump speed to demand and eliminating the need for adjustable impellers.

The drive units are all rated at 600kW and will operate from April until the middle of October, each year, when they are turned off due to the seasonal drop in ambient temperature.

The drives were used to change the motor supply frequency, which was increased from 50Hz to 55Hz, increasing the motor performance and hence the refrigeration capacity.

This allowed the original system design to be used with the new refrigerant and yet still provide increased overall performance.

Carrier chose the FID 3000 drives not only for their dynamic performance, but also because of FKI's background knowledge of applying their drives and interfacing with sophisticated Carrier control units.

FKI also provides twelve pulse drives that are very low in current harmonics, making them supply friendly.

The "supply friendly" aspect of the drives was of particular importance due to the large amounts of power required by the pumps in the chiller plants.

This meant that their demand interference on the mains supply had to be considered carefully.

FKI also carried out a full harmonic survey as part of its overall service package to Carrier/Jaguar.

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