Choosing a motor starter for filter systems

Energy savings:

• Naturally, power is saved when the fan does not always run at constant speed, but adjusts its speed according to extraction requirements.

• Correctly regulated airflow over the filter ensures minimum pressure drop, keeping the fan speed at a minimum. Note that the pressure drop over the filter changes day by day.

• With a variable number of extraction points, you are ensured that not too much heated hall air is vented outside when only a few extraction points are active.

Filter lifespan:

• Constant pressure regulation of the fan ensures that the filter system is not overloaded. This increases the lifespan of the filter elements.

• All other starters (soft starters, Y/D starters and motor protection circuit breakers) operate the fan at full speed, which means regulation must be done by dampers. Since the pressure drop over the filters and the number of extraction points are variable, adjustment must be done several times daily to avoid overloading the filters.

• When changing filter cartridges on systems without regulation, the new filters will have a very low pressure drop, and the fan can therefore draw significantly more air through the filter than it is designed for. This can result in acute clogging within a few months. On a system with filter cartridges for 10,000 m³/h with welding fumes, this can result in additional costs of over DKK 50,000 for replacing with new filter elements (including installation).

• Correct and constant adjustment of airflow can increase the lifespan of filter elements by up to 50%, as overload periods are avoided. On a system rated for 10,000 m³/h, this can typically result in savings of up to DKK 6 per operating hour.

Explosion and fire hazards:

• All process extraction systems must ensure airflow velocity in the duct system to prevent material build-up. This requires demand-based fan regulation, as increasing pressure drop over the filter will reduce vacuum and thus airflow in the duct system.

Operational reliability:

• With demand-based regulation of the fan, the strain on the motor is reduced, which extends its lifespan.

   

• Pressure-controlled operation of the fan also prevents sudden pressure surges, which can cause ductwork collapse.

System integration:

• The frequency converter, via its signal inputs and outputs, also enables integration with other system automation, such as start/stop automation for control of motor dampers and air ventilation systems for coordinated air exchange.