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Integrated VSD Compressors: 8 Key Advantages

The following is an excerpt from the article Integrated VSD Compressors: 8 Key Advantages by Deepak Vetal, product marketing manager, oil-free screw, centrifugal, and high-pressure air, Atlas Copco Compressors

Variable speed drive (VSD) technology offers a range of benefits to operators. Because it works to meet flow demand, VSD helps plants save significant amounts of money and reduce their carbon footprint. But not all VSD technology is equal. Operators can install an external VSD to accompany a fixed-speed, base load compressor to suit it for trim duty. The standalone drive is connected to a fixed speed compressor and wired to the motor to adapt to the variable demand. While initially less expensive than integrated VSD compressors, external VSD equipment can cause far-reaching issues that impact compressor performance and total lifetime cost.

Instead of retrofitting fixed-speed compressors with external VSDs, operators looking for a new compressor for trim duty or other variable demand applications should invest in an integrated VSD compressor. Unlike external VSD components, integrated VSD compressors combine the compressor motor and variable speed drive together in a single product. Utilizing an integrated VSD compressor offers eight key benefits beyond that of external VSD technology that can help operators achieve higher performance levels and fewer maintenance issues throughout the life of the machine.

1) Inverter duty motor

Inverter duty motors are specially designed to have higher cooling air flow, allowing them to run at lower speeds without overheating. These motors maintain high efficiency throughout the entire speed range while providing sufficient torque. Using a fixed speed motor in a variable speed drive application can have a negative effect. As the speed reduces, cooling air flow will reduce according to a square of the speed reduction. Thus at 90 percent speed, there is only 81 percent flow. This can lead to overheating of the windings and a consequent reduction in efficiency and motor torque.

For example, let’s take a look at a compressor motor which needs 1000 cfm air flow for cooling. When we use a standard fixed speed motor, we reduce the speed of the motor by 90 percent. The cooling flow is then reduced to 810 cfm, which could overheat the motor.

When a motor overheats, the torque created may fall below the required amount. This means restricting the speed range of a standard motor, whereas inverter duty motors will maintain the required torque even down to the lower speed limit. With an inverter duty motor you can get more ‘turndown’ and more energy savings.

Keep Reading…

You can read the full article on the benefits of an integrated VSD package in Plant Engineering’s September issue. To learn more about Atlas Copco’s line of VSD compressors, contact our experts today or leave a comment below.

Source:hopnhatvn.com