The two most common motor-control methods are: DC Chopper control and Phase Angle control. This article explores the differences between the two methods, identifying some of the key trade-offs that can be useful for motor-control designers when determining which is the best control method to use for their specific application. Shown in Figures 1 and 6, respectively, the triac control
Click here to download the full size of the above Circuit.
and chopper control circuits used to drive the universal motor can be used in a very simple household appliance. The main difference is that the triac and Gate Drive Transistor in the Phase Angle control circuit are replaced by an IGBT. The chopper circuit also introduces in a full-wave rectifier to the AC line circuit because the IGBT only conducts current in one direction. The main principle behind the Phase Angle control circuit is that the microcontroller (MCU) is used to vary the firing angle to the triac. By adjusting the firing angle to the triac, i. e. , the point in the AC voltage waveform where the triac turns on, the voltage applied to the motor can be modulated and the speed of the motor can be regulated. The firing angle of the triac is referenced to the zero crossing of the AC waveform, which is sensed using a zero crossing detect circuit on the line voltage. The MCU uses a special timer that emits a series of one-shot pulses into the gate of the triac to turn it on. A series of pulses are recommended as opposed to just a single pulse per cycle, because the motor is an inductive load, and a pulse train ensures the triac conducts current in both positive and negative directions. An illustration of this principle can be seen in Figures 2 and 3. In Figure 2, the gate pulses to the triac are for roughly one third of the duty cycle of the voltage waveform. The triac is conducting during this time. In the...
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.....
characters left: