Phase failure indicator. Scheme, description

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

Phase failure indicator

Free technical library

Encyclopedia of radio electronics and electrical engineering / Protection of equipment from emergency operation of the network, uninterruptible power supplies

Comments on the article

It is well known how dangerous it is for a three-phase electric motor to lose voltage in one of the phases. Only an experienced power specialist can notice this in a timely manner by changing the sound, since the engine often continues to work, but quickly overheats and burns out. In production, special protective devices are used that automatically turn off the engine when the phase voltage fails. However, for domestic use, such devices are unreasonably expensive. The proposed indicator will help prevent an accident, signaling a malfunction not only with a light signal, but also with an audible signal.

The simplest indicators of the health of a three-phase network can be neon lamps connected through quenching resistors between each phase wire and neutral.

Since the attention of a person is absorbed, as a rule, by the work performed, he may not notice the extinguished lamp in time. An audible signal is required to draw attention to an emergency situation. In addition, neon lamps sometimes flash randomly, so it is better to use LEDs for signaling.

The scheme of the developed indicator is shown in fig. one.

Phase failure indicator

The presence of voltage in each of the phases is controlled using three identical detectors. For example, the phase detector A consists of a diode VD1, a resistive divider R3R7, a smoothing capacitor C4 and a zener diode VD9 that limits the rectified voltage. With a good phase, the voltage level at the output of the detector corresponds to the log. 1, if faulty - log. 0.

With a fully operational network log. 1 are present at all inputs of the element DD2.2 and log. 0 at its output blocks the operation of the tone generator on the DD1 chip. Elements DD2.1 and DD2.3 control the LEDs HL1 and HL2, the glow of which indicates the presence of voltage, respectively, in phases A and B. The phase C indicator - the HL3 LED - is controlled by a key on the transistor VT2. This is done so as not to add another microcircuit to the device.

In the event of a failure of one of the phases, the corresponding LED will go out, log. 0 at the output of the element DD2.2 will change to log. 1 and the generator on the elements DD1.1, DD1.2 will start to generate pulses with a frequency of 2 ... 3 Hz, which will periodically turn on the audio frequency generator on the elements DD1.3, DD1.4. As a result, an intermittent sound signal will be heard from the piezoceramic emitter HA1.

The indicator is powered by two identical rectifiers (C1. R1. VD4 and C2. R2, VD5), the inputs of which are connected to different phases of the network, in this case, B and C. Thanks to the diodes VD6 and VD7, the device actually feeds one of the rectifiers, the output voltage of which A bit more. And if one of the phases fails, the power continues from the other, the indicator remains operational. The supply voltage of microcircuits is additionally stabilized with the help of a VD8 zener diode.

The indicator is assembled on a printed circuit board shown in fig. 2.

Phase failure indicator

Resistors R1-R5 -MLT-0,5. Less powerful ones are not recommended for electrical safety reasons. Resistors R10 and R17 - MLT-0,125, the rest - size 1206 for surface mounting (PM). Oxide capacitors - K50-35 or the like for a voltage of at least 16 V. Capacitors C1, C2 - K73-17 for a voltage of at least 250 V, C7 - K10-17, all others - ceramic size 1206 for PM. All elements for PM (resistors and capacitors) are mounted on the side of the printed conductors, soldering directly to the pads.

Instead of K561 series microcircuits, you can install (without changes in the circuit) their functional analogues from the K176 series or imported CMOS microcircuits. Transistors KT3102A can be replaced by others of the same series or series KT315, KT3117. As zener diodes VD8-VD11, any with a stabilization voltage of 7 ... 9 V (for example, KS175A, D818 with any index) are suitable, but for VD8 it should not be less than for VD9 VD11. Zener diodes VD4, VD5 are replaced by others for a voltage of 10 ... 15 V, for example, KS515A. Diodes KD209A can be replaced with KD105B or KD102B. As LEDs HL1-HL3 any suitable, preferably high brightness. HA1 - - piezoceramic sound emitter ZP-1 or similar.

A correctly assembled indicator does not need adjustment and starts working immediately after switching on. If necessary, you can change the frequency of the audio signal by choosing the value of the resistor R11 or capacitor C11.

Author: I.Korotkov, Bucha village, Kyiv region, Ukraine

See other articles Section Protection of equipment from emergency operation of the network, uninterruptible power supplies.

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

Xiaomi Mobility Intelligent AI massage chair 18.12.2018

Xiaomi has announced a new device for home use. The device has traditionally received the most detailed name - Mobility Intelligent AI Full Body Massage Chair.

Artificial intelligence in the description is not mentioned by chance - the chair itself determines the position of the massage area (for example, the neck) and massages it. This ensures full compliance with the anthropometric parameters of different people.

The chair provides six modes of classic massage treatments in combination with different techniques and areas. So, you can start a massage of the whole body or just the neck, back, legs or arms. The Mobility Intelligent AI Full Body Massage Chair uses a voluminous and long (125 cm) massage element, due to this, a better study of individual zones in the full body massage mode is provided.

The device allows you to provide the so-called zero gravity state - it leans back at an angle of 126+-7°, as a result of which the body weight is evenly distributed over the chair, reducing pressure on the spine and limbs.

The Mobility Intelligent AI Full Body Massage Chair features an intercom. It is easy to notice the absence of a traditional push-button control panel - the chair is controlled by voice. It remains to be added that although the device did not turn out to be very cheap, at a price of $1160 it is much more affordable than analogues known in this segment.

Other interesting news:

▪ Wounds heal faster

▪ Tunnel under the Yangtze

▪ Ultra-low power DACs from National Semiconductor

▪ Fantasists turned out to be altruists

▪ Comet Neowise is closest to Earth

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site for the radio amateur-designer. Article selection

▪ Article Urology. Lecture notes

▪ article Which city's mayor beat his rivals in SimCity before winning the election? Detailed answer

▪ article Dill fragrant. Legends, cultivation, methods of application

▪ article Automatic car battery charger. Encyclopedia of radio electronics and electrical engineering

▪ article Peat electrical installations. Grounding. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

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