An ac drive controls ac induction motors and, like its dc counterparts, controls speed, torque, and horsepower. A dc drive typically controls a shunt-wound dc motor, which has separate armature and field circuits. This teardown of the Schneider Electric Altivar 12 variable-frequency drive details the key features that define these drives. Rotating
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equipment, including fans, blowers, compressors, and pumps, consumes more than one-third the total electrical energy generated in the United States. This equipment may use variable-speed-drive technology, in which motor speed adjusts to meet the load requirements, yielding an advantage in both improved productivity and reduced energy consumption. For example, lowering fan or pump speed by 15 to 20% enables a decrease in shaft power of as much as 30%. Properly applied variable-frequency drives are affordable, reliable, and flexible, and they offer a significant amount of savings through reduced electric bills. Electronic variable-frequency drives vary the voltage and frequency to induction motors using pulse-width modulation. The drives use insulated-gate bipolar transistors to convert the fixed-frequency ac supply voltage to a variable-frequency, variable-voltage ac supply to the motor and can regulate the speed of an induction motor from approximately 10 to 200%; wider ranges are possible. The drives also regulate the output voltage in proportion to the output frequency to provide a relatively constant ratio of voltage to frequency to produce adequate torque. The Altivar 12 manual recommends that you remove the vent covers for IP (ingress protection) Type B and C mounting when IP20 protection is adequate but that you leave them on the housing in Type A mounting (Figure 1). ANSI/IEC 60529-2004 describes the degrees of...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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