NEWS: Why do I need a Variable Speed Drive compressor?

What’s the difference between traditional and VSD?

The main difference between a Fixed Speed and a Variable Speed Drive (VSD) air compressor is efficiency and adaptability to demand:

A traditional Fixed Speed air compressor operates based on preset cut-in and cut-out pressure settings. When running on load, it consumes maximum kW power, while in off-load mode, it still uses approximately 30% of its full load power. During off-load operation, the compressor idles, waiting for the pressure to drop before restarting. This idle running results in wasted energy, making it less efficient in applications with fluctuating air demand.

By contrast, Variable Speed Drive air compressors automatically adjust the compressor’s operating speed to match demand in real-time. Given that many industrial operations do not require continuous use at full capacity, VSD compressors can save significant amounts of energy, and running cost.

The energy/cost equation

The greatest cost in industrial air compressor ownership is energy usage, representing about 70% of the cost of total ownership. A VSD system typically costs more to purchase at the outset than a similar fixed speed system, but the extra expense is regained through energy saving. In fact, a VSD compressor system can reduce energy costs by 35% – 50% and the newer VSDs technology achieves an impressive 60% saving. This saving will cover the additional investment whilst reducing energy usage as an ongoing benefit and supporting sustainability goals.

How does it work?

A VSD compressor regulates its speed (RPM) using an inverter, which adjusts the voltage based on demand. Unlike conventional AC motors that operate at full capacity continuously, the inverter ensures the compressor receives only the necessary power, improving energy efficiency.

Next generation VSD^S performance

Atlas Copco’s state-of-the-art GA VSD^S air compressors deliver superior performance. Considered the gold standard of environmentally friendly air compressors, the latest models were developed with reduced energy consumption as the core goal. They feature fewer components, sustainable materials, and a new ferrite-assisted synchronous reluctance motor that does not rely on rare earth metals.

Every aspect of the system has been refined to ensure that IE5 standards energy efficiency and IP54 dust and dirt protection are met. A Smart Temperature Control system maintains optimal oil temperature. A new inlet filter provides enhanced filtration efficiency whilst minimising pressure drops. The outcome of this fine tuning is a remarkable energy saving of up to 60%.

Where is a VSD beneficial?

A VSD is a smart choice for optimum efficiency and energy saving:

• Where there is a fluctuating demand for compressed air as opposed to continuous flow.
• Where demand varies by shift, weekends or seasonally.
• Where tight operating pressure tolerances are required.

Models range from small compact units to large industrial systems, so there is a VSD to suit all business sizes.

Examples of end use:

• Manufacturing & Automotive
• Food & Beverage
• Pharmaceutical & Healthcare
• Textile Industry
• Electronics & Semiconductor
• Oil & Gas
• Chemical & Petrochemical

Where is a traditional fixed speed compressor the right option>?

Traditional fixed-speed air compressors can only operate at full capacity, so are best suited to situations where full capacity is necessary. A VSD compressor is not intended for constant operation at full speed.

Which system do I need? – Get an audit

The best way to determine if you could benefit from a Variable Speed Drive air compressor is to get a professional air audit.  At ACL we find that costs can be considerably reduced through the right choice of compressor model and size, alongside other key evaluations and considerations.