02.11.2013 18:04

Variable speed control with a variable speed compressor

Variable Speed Compressor

Being able to vary the speed of a compressorís function allows for a greater degree of both control and flexibility. Variable speed control for all types of industrial compressor is now commonplace in the market. This is largely because the costs compare favourably with compressors that have no variable speed functionality. As a consequence, variable speed compressors are now much more commonly used than ever before and they have multiple applications, including many that are in the air compression industry.

There are significant benefits for systems served by variable speed compressors where demand changes from time to time because, by varying the frequency of the input electricity to the motor, the system is able to speed up and slow down. Ideally, this change in speed will be one that matches the supply output to meet the demand. However, the variable speed compressor must do this whilst maintaining a stable operating pressure within the system.

The most common form of variable speed compressor technology is in the air compressor industry, but it is also used by the manufacturers of products such as fridges. Generally, a variable frequency drive changes the source power, in alternating current, to direct current. After this, the power is then turned back into a quasi-sinusoidal alternating current by means of an inverter switching circuit. With the power set, it is possible to engineer the compressor so it can vary, depending on demand.

Variable speed control for air compressors is an important component of an optimised airflow system, say in a factory or an office, but it needs to be appropriately applied. Many factors must be thought about prior to variable speed compressor being chosen for an air compression system, not least the correct size of compressor. A skilled engineer in usually required to take all of the systemís unique specifications into consideration before one is selected.

In a typical industrial environment twenty per cent of an establishmentís electricity costs can be put down to the production of compressed air. Many contemporary production line managers are focussed on cost cutting and, as energy prices continue to rise, so awareness around variable speed air compression has risen. Significant cost savings can be made by employing a variable speed drive compressor instead of traditional technology, such as a rotary screw or a piston machine. However, the systemís controller must be capable of maintaining the most pressure uniformly and, in the case of larger systems, this means among multiple compressors. Otherwise, the cost reduction associated with a variable speed compressor will not be noticed.

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