Imagine you have a regular light switch and a dimmer switch for a light bulb. A regular switch only has “on” and “off,” while a dimmer lets you control how bright the light is. A VFD is like a dimmer switch for a fan motor – it lets you control the fan’s speed. Changing the fan’s speed with a VFD also changes the motor’s horsepower (its ability to do work) and torque (its turning power). Let’s break it down for centrifugal fans (the most common type).
VFD fan control
Know the Speed/Power/Torque Trade-Off for Your Application
Did you know that when you control and vary the operating speed of your industrial centrifugal fan or blower using a variable frequency drive (VFD), you’re affecting both horsepower (HP) and torque? It’s not always obvious, but it’s important to understand when you may be operating at reduced power or torque due to changes in speed because you always need a certain horsepower to drive the fan and move air through the type of pressure in your system.
Maintain Static Pressure with VFD for Air Flow Control
Using a variable frequency drive or VFD for air flow control on your industrial fan can increase efficiency and save on energy costs over time. That’s because it gives you a high degree of control while keeping the airstream clear, thus avoiding static pressure losses that inevitably reduce efficiency.
VFD Motor Control for Overspeeding Industrial Fans
Once upon a time, direct-drive industrial fans could only go one speed. With the invention of the Variable Frequency Drive (VFD), industrial manufacturers gained a great degree of control and the ability to overspeed the fan for optimal operation in the application through which it is moving process air.
VFD or Fan Damper?
Industrial fan installation and applications are full of choices, big and small, immediate and long-term. One of the small choices that can make a big difference in the long term is whether to use a Damper or a Variable Frequency Drive (VFD) to control the capacity of your industrial fan. While some may choose both options depending on their applications, many fan users make an “either-or” decision.