Information Sheet #7 - Variable Frequency Drive Applications & Explanations.
Variable Frequency Drive, usually using the acronym VFD, refers to the technology for fine control of motors with an electro-mechanical drive system. VFD has two principal benefits, first a more efficient way to start and ramp up an electric motor, and secondly a method for finely controlling motor speed and/or movement with a wide range of systems, including but not limited to, continuous manufacturing process, industrial and commercial machinery and water-treatment plants. While the technology is not new, the advancements in digital switching technology has greatly accelerated the use of the VFD.
2.0 Explanation of VFD Technology:
The primary purpose of a VFD is precise control of electric motor speed. With a VFD, a system designer can precisely control ramp up and ramp down speed to ensure all the components within a process are coordinated and operate efficiently in sync. Without a VFD an AC electrical mechanical device, such as a constant electric motor, just runs up to constant speed as current is applied and while doing so consumes up to 7-times the running amps required, to overcome starting torque. Prior to the application of VFD, motors would have to be connected to various mechanical components such as gears.
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Information Sheet #11 - Brownouts & The Adverse Effect On Electric Induction Motors.
This information sheet discusses the adverse effect brownouts have on electric motors, particularly induction motors and how to manage them.