Soft switching on of powerful loads. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Clocks, timers, relays, load switches

 Comments on the article

In circuits with a powerful load and a high switching frequency, electromagnetic relays and starters have been replaced by power semiconductor switches with optical isolation. Currently, there are devices that allow them to be used in systems with direct control from the logic levels of microcircuits such as TTL, TTLSH, CMOS, etc.

For AC circuits, preference is given to microcircuits with the inclusion of an electronic key at the moment the voltage passes through zero. This eliminates large impulse noise, the occurrence of switching voltage surges due to a fantastic shift between current and voltage, and also reduces the requirements for network filters or eliminates them.

Spontaneous switching on of power triacs due to random voltage surges when switching the windings of electrovalves or electric motors can lead to an interphase short circuit. To eliminate this, shunting of the power outputs with a damping RC circuit is used. When powerful loads are turned on at low (close to zero) voltages, the amplitude of current pulses decreases significantly when working with capacitive loads. In addition, triacs operate in a soft mode and their reliability increases dramatically.

Typical representatives of non-contact power switches are MOC3031M/32M/ZZM opto-isolators. MOC3041M/ 42M/43M. MOC3061M / 62M / 63M, MOC3162M / 3163M, MOC3081 / 82/83 [1] (there is also a similar description with the Fairchild Semiconductor logo), produced in a 6-pin DlP package (Fig. 1). They consist of an infrared emitting diode optically coupled to a two-way voltage zero-crossing detector and an output opto-triac. These elements are convenient for use with high power triacs, solid state relays and other industrial controls.

Microcircuits, the marking of which ends with 1, 2 and 3, ensure that the load is turned on when a current is applied to the LED, respectively equal to 15, 10 and 5 mA. The voltage drop across the infrared LED is 3 V. Microcircuits, the penultimate marking digit of which ends with 3,4,6 and 8, are designed for switching circuits with a maximum voltage of 250, 400, 600 and 800 V, respectively. The maximum switching current is 1A at turn-on duration 100 µs. The maximum continuous switching current is 60 mA.

The circuit for switching on microcircuits for controlling a triac is shown in fig. 2.

For MOC303X / MOC304X / MOC306X / MOC308X, the resistance R1 should be 180, 360, 360 and 360 ohms, respectively. R2 - 1 kOhm, 330, 360 and 330 Ohm. The output current of the IC can reach 1 A, but only at the moment the power triac VS1 is turned on. therefore, you cannot use this output as a burdock output, loading it with a constant load. Only one triac can be connected to one output.

More powerful triacs can be connected to the microcircuit through intermediate amplifying triacs.

The table shows the recommended triacs for direct connection to devices.

Triacs must be mounted on radiators. It should be borne in mind that the operating currents switched by triacs depend on temperature. Obsolete TC 161 triacs require a unipolar turn-on signal and cannot be operated from these microcircuits.

Instead of triacs, thyristors connected in anti-parallel can be used as power elements (Fig. 3).

The resistor values ​​are selected in accordance with the recommendations for Fig. 2, diodes - 1 N4001.

In [2], the main types and parameters of Russian-made modules are given.

Information sources

1. 6-Pin DIP Zero-Cross Optoiso-lators Triac Driver Output (800 Volts Peak). Motorola Semiconductor Technical data.
2. L. Rachinsky, A. Sanchugov. New power semiconductor hybrid modules with optical decoupling of the MGTSO series. - Power electronics, 2006. No. 2, p.60.
3. termodat.spb.ru/out. htm
4. O.V. Belousov. Electronic load switch. - Radioamator, 2007, No. 11, p.XNUMX.
5. O.V. Belousov. Electronic load switch. - Radio amateur, 2008, No. 3, p.12.
6. V.A.Melnik. Zero detector on the microcontroller. - Radiomir, 2008, No. 4, p.23.
7. A. Kashkarov. Options for switching on relayless terminal electronic nodes. - Radio amateur, 2008. No. 1, p55.

Author: V.Melnik. Dneprodzerzhinsk, Ukraine

See other articles Section Clocks, timers, relays, load switches.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive LG Stops Production of Plasma TVs 28.08.2014 South Korean consumer electronics maker LG Electronics has announced plans to discontinue production of plasma (PDP) TVs in the near future amid weak demand for these products. "We are currently conducting an internal study regarding the timing of the completion of the PDP business. An official statement on this matter will be made at a later date," said Hyun-hwoi Ha, head of LG Home Entertainment division, without providing further details and a specific timeline. In early July, Samsung SDI, which, as part of the South Korean conglomerate Samsung Group, specializes in the development of batteries, announced the abandonment of plasma in early July. The company will curtail the production of plasma panels by the end of November 2014, after which it will fully focus on the production of chemical and electronic materials, as well as the energy business. The decision to abolish the PDP business of both LG and Samsung SDI was attributed to declining sales of these devices. According to IHS analysts, in the first quarter of 2014, global shipments of plasma TVs fell by 16% compared to the same period last year and amounted to 2 million units. Experts from DisplaySearch predict that no more than 2015 million such products will be released to the world market in 5, compared to 10,3 million units in 2013.

Other interesting news:

▪ The anticipation of the holiday affects the sense of time

▪ Found an important difference between the human brain and other primates

▪ Technique against pirates

▪ Bulletproof vest with cooling system

▪ Superconductor without limits

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Art video. Article selection

▪ Article Law of Archimedes. History and essence of scientific discovery

▪ article Caterpillars of which butterflies are forced to hibernate for up to 13 winters before turning into a chrysalis? Detailed answer

▪ Janitor article. Standard instruction on labor protection

▪ article Electronic ballasts. Advantages. Encyclopedia of radio electronics and electrical engineering

▪ article Choosing an intermediate frequency. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024