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A vacuum fluorescent display (VFD) is a display device once commonly used on consumer electronics equipment such as video cassette recorders, car radios, and microwave ovens. A VFD operates on the principle of cathodoluminescence , roughly similar to a cathode-ray tube , but operating at much lower voltages.
Small variable-frequency drive Chassis of above VFD (cover removed). A variable-frequency drive (VFD, or adjustable-frequency drive, adjustable-speed drive, variable-speed drive, AC drive, micro drive, inverter drive, variable voltage variable frequency drive, or drive) is a type of AC motor drive (system incorporating a motor) that controls speed and torque by varying the frequency of the ...
With a variable-speed drive on the pump or fan, the supply can be adjusted to match demand and no extra loss is introduced. For example, when a fan is driven directly by a fixed-speed motor, the airflow is designed for the maximum demand of the system, and so will usually be higher than it needs to be.
If a variable speed drive compressor operates continuously at full speed, the switching losses of the frequency converter result in a lower energy efficiency than an otherwise identically sized fixed speed compressor. Where demand remains constant within 5–15% of the total free air delivery flow rate, dual-control compressors configured in a ...
Variable-frequency drive, on electric motors; Virtual Floppy Disk (file type), in Microsoft Virtual PC; Other uses. V.F.D., a recurring acronym in A Series of ...
This article is a subtype of variable speed drive, of which there are many beyond just electronic means. That DoE PDF says this right in the 2nd paragraph of the first page: Speed can be controlled in a number of ways, with the most popular type of variable speed drive (VSD) being the variable frequency drive (VFD).
For the same application, the program would select a 125 kW gen-set when using a variable frequency drive and a primary reactor bypass with a 30% starting voltage drop, cutting the gen-set in half (Slides 36–39). [5] Energy Savings – "Most motors turn at nearly constant speed. However, much of the time the devices they drive operate at less ...
The only difference between DTC and DSC is the shape of the path along which the flux vector is controlled, the former path being quasi-circular whereas the latter is hexagonal such that the switching frequency of DTC is higher than DSC. DTC is accordingly aimed at low-to-mid power drives whereas DSC is usually used for higher power drives. [6 ...