Free phone 0508 763 862

Compressed Air Controls on YouTube Compressed Air Controls on LinkedIn


Key features: 

  • ELGi's own superior technology airend for volumetric efficiency
  • Thermo-zoned layout to ensure cool running and maximum Uptime
  • Three-stage air filtration system
  • Oil carry-over <1ppm
  • Highly efficient motor
  • Low sound level <69 dBA
  • Easy access to routine service points
  • Safety compliant package
  • Equipped with advanced controller for remote monitoring 
  • Integrated with VFD and dryer options for greater energy savings

* Products available in 50Hz and 60Hz based on the market requirements.

ELGi saves you energy and money

ELGi’s EG screw air compressors save you energy and money through their variable frequency drive (VFD).

If your compressor’s unload hours on an HMI/hr meter are 15-20 percent of total run hours, there is a potential to save energy through a VFD.

Contact us for an Air Data (AD) assessment.

What is a VFD?

The VFD is a type of adjustable-speed drive to control the motor speed by varying the frequency applied it.

What does adjusting the speed do?

The motor speed is directly proportional to the frequency and thus changes in frequency impact the motor speed and the amount of power consumed. 

The VFD can transform air compressors that have traditionally been known as power guzzlers into energy-efficient equipment.

How much energy can be saved?

Once it is fitted with a VFD, the energy cost of an average compressor comes down by 18 percent. 

This calculation is based on the assumption that it is a compressor with a running life of 15 years, runs 24 hours a day and has a load-unload cycle of 70:30. 

Examples of cost savings with VFD

An India-based automobile company recorded around 40 percent savings in its power costs after fixing VFDs in its ELGi EG 37-7.5 compressor. 

The company uses compressed air for applications such as castings for sandblasting, painting and dust removal. 

The company received the ROI in just six months. 

Since the heat generated in the compressor reduces with the VFD, the company can also expect better longevity of the compressor’s parts like the intake valve and air-oil separator, and extended oil life.

Three ways to save energy

  • 25 percent energy savings due to the elimination of the unload cycle.

In general, compressors work in the load-unload mode. 

When there is demand, compressor loads and allows the pressure to rise, and unloads once it reaches the unload pressure set point. 

The compressor cannot be turned off since the motors are not designed to frequent switching on and off. 

During the unload cycle, the intake valve closes and there is no air flow, but the motor continues to run at the rated speed. 

The compressor consumes 25-30 percent of power. 

With VFD, there is no unload cycle, and air continues to be produced at the required pressure.

  • 7 percent energy saving due to reduction in operating pressure.

If an application requires an operating pressure of 6 bar, the fixed speed machine operates on load-unload set points which are 6 and 7 bar, respectively. 

To compress an extra 1 bar, approximately 7 percent of additional energy is spent, which is a waste.

In a VFD-powered compressor, the pressure is maintained constantly throughout and this loss is eliminated.

  • 3 percent energy saving due to leakage and pressure drop reduction.

Air leakages and pressure drops are inevitable in any compressed air system.

For every 1 bar increase in compressed air pressure, there is a corresponding 3 percent higher rate of leakage and pressure drop in the compressed air circuit, which demands extra power. 

Since a fixed speed machine requires 1 bar extra over the desired pressure, it is bound to lose energy on this account. 

In VFD-powered compressors, the pressure is maintained constant throughout the cycle and leakage losses due to increase in pressure are eliminated.

VFD compressors are highly effective ways to save energy during a compressor application.

If the requirement is 900 cfm, the base load will be shared by load-unload compressor of 400 cfm and the trim load will be shared by the 500 cfm VFD compressor.

Share this with your work colleagues

Share on Facebook Share on Twitter Share on LinkedIn Share using email