Variable Frequency Drives (VFD) are actually a motor controller responsible for driving an electric motor. This is accomplished by varying both the voltage and frequency applied. Because the frequency has a direct link to the speed at which the motor operates, also referred to as RPMs, the faster the frequency, the faster the RPMs.
In the event that the full speed of the motor is not required, the Variable Frequency Drive works by reducing voltage and frequency so that the speed requirements of the motor’s load are met. There are a number of benefits that go hand in hand with using this type of motor controller.
- Energy Consumption and Costs – A VFD helps reduce energy consumption and cost. As mentioned, if the full speed is not required for a certain application, energy consumption is less and energy costs decrease. Today, over 65% of all power consumption in industry comes from electric motor-type systems. By optimizing these with a VFD or even upgrading an existing VFD, energy consumption would be cut by up to 70%. Obviously, when less energy is used, the cost goes down.
- Improved Production – Variable Frequency Drives also improve the quality of the finished product while reducing operating costs. Especially in a world where the end-user demands perfection, having the opportunity to produce a much higher-quality product for less money is extremely beneficial for all parties.
- Tax Incentives and Rebates – It is quite common to see tax incentives coming from the government and rebates from utility companies for manufacturers who follow more energy-efficient practices. With the installation of a VFD, people can take advantage of these perks, which bolsters the return on investment.
- Tighter Process Control – When a motor is operated at a more efficient speed, regardless of the application, the number and severity of errors decline dramatically. Because of this, production levels increase. Ultimately, having a tighter process control equates to more revenue being generated. In addition, manufacturing companies experience a higher output because jerks are eliminated when starting conveyer belts.
- Longer Equipment Life – With Variable Frequency Drives, equipment lasts longer. Due to the optimal control over the motor’s voltage and frequency provided by a VFD, there is a greater level of protection. In other words, there is less risk of the motor experiencing under-voltage, electro-thermal overload, overvoltage, phase protection, and so on. In addition, gears, belts, and bearings wear down less often because of a smooth startup. Even water hammer is eliminated or, at a minimum, reduced because of seamless accelerations and decelerations. Not only will equipment last longer, a VFD reduces the need for maintenance.
- Improved Starting Characteristics – Variable Frequency Drives are also beneficial in that they can bring a motor up to full speed very quickly while drawing just 100% to 150% of full-load amps. This is accomplished when a VFD manages the magnetic flux specific to an induction motor. In keeping a constant flux, the inrush current does not exceed the rating for full-load amps although full torque is maintained.