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2. Variable-frequency drive - Wikipedia

   en.wikipedia.org/wiki/Variable-frequency_drive

   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 ...

3. Vector control (motor) - Wikipedia

   en.wikipedia.org/wiki/Vector_control_(motor)

   Vector control, also called field-oriented control (FOC), is a variable-frequency drive (VFD) control method in which the stator currents of a three-phase AC motor are identified as two orthogonal components that can be visualized with a vector.

4. Motor drive - Wikipedia

   en.wikipedia.org/wiki/Motor_drive

   When changing VFD frequency in standard low-performance variable-torque applications using Volt-per-Hertz (V/Hz) control, the AC motor's voltage-to-frequency ratio can be maintained constant, and its power can be varied, between the minimum and maximum operating frequencies up to a base frequency. Constant voltage operation above base frequency ...

5. Variable-speed air compressor - Wikipedia

   en.wikipedia.org/wiki/Variable-speed_air_compressor

   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 ...

6. Direct torque control - Wikipedia

   en.wikipedia.org/wiki/Direct_torque_control

   Thus it is not possible to control the motor if the output frequency of the variable frequency drive is zero. However, by careful design of the control system it is possible to have the minimum frequency in the range 0.5 Hz to 1 Hz that is enough to make possible to start an induction motor with full torque from a standstill situation. A ...

7. Variable speed fire pump controller - Wikipedia

   en.wikipedia.org/wiki/Variable_speed_fire_pump...

   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 ...