|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Solar emergency lamp. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Alternative energy sources Power outages are not only accompanied by inconvenience and mood deterioration, but are also a clear source of danger. A well-lit staircase, hallway, or work area can be a potential hazard during a power outage. With a sharp onset of darkness, the likelihood of a fall, and with it an accident, increases. To avoid accidents, you can install an emergency system that will provide temporary lighting to areas that pose a potential danger during a power outage. With such lighting, you can safely leave the house or make the necessary repairs, for example, change a blown fuse. Principle of operation The emergency lighting system is designed to provide light when the main power source fails. The operation of the system is based on the use of energy stored in the battery, constantly maintained in a charged state. A block diagram of a typical emergency lighting system is shown in fig. 1.
A special sensor monitors the voltage in the AC network. It contains a relay that turns on the emergency lighting circuit when the AC power fails. The backup lighting circuit consists of a battery and a lamp connected in series with relay contacts that act as a two-position switch. The battery is the only source of electricity during a mains power failure and therefore must always be kept charged. That's when photovoltaic converters are needed. They convert solar energy into electricity and charge the battery. Emergency system design The basis of the design of the emergency lighting system is a solar battery. To select the right photovoltaic generator, two parameters must first be determined: the operating voltage and the current consumption of the emergency light. Let's start by determining the required illumination. It should be enough to illuminate the working area at any time. Typically, emergency systems use a sealed lamp (spotlight) rated for 12 V. This choice is due to two reasons. Firstly, such a lamp meets the requirements for illumination, having sufficient brightness and reliability. Secondly, it requires power from a low-voltage source. Moreover, it is easier to power a 12-volt lamp from a single 12-volt battery than to connect several batteries to power a conventional incandescent lamp. This makes it possible to design a compact and reliable device. Installing a low-voltage emergency lighting system in your home will be less of a concern than a similar system powered by 110V AC. Based on residential regulations, a 110V system is more expensive and, once installed, usually requires approval by the appropriate inspector. It is a completely different matter with low-voltage systems, which are quite safe to install and operate, and it is extremely rare to check their operation. In addition, low-voltage emergency lighting does not require special precautions in conditions of high humidity (rain or storms) and can be operated without fear of electric shock. Description of the system The power consumed by the system depends entirely on the type of lamp used. A car headlight was chosen because it provides sufficient illumination, and is also cheap and readily available. This lamp draws about 2 A at 12 V. The headlight is then connected to the battery. The required battery capacity is directly proportional to the length of time following a power failure. Usually a few minutes is more than enough to get everything in order. It is believed that 1 hour is the longest time it could ever take to restore lighting. With all of the above factors in mind, a 6Ah, 12V lead-acid battery was chosen. It will provide energy to light up a room for 2,5 hours - more than enough time. These batteries are commonly used to power motorcycles. Photovoltaic converters Typically, you will need a 12V solar panel that delivers 1A. These batteries are quite affordable, and so you can immediately pick up a battery of the required power. Sometimes solar cell kits are sold that allow you to make a solar battery yourself. If there is a desire to assemble a solar battery from individual elements, it is recommended to use the most common round elements with a diameter of 7,5 cm. It will take only 35 elements. Using the Charge Regulator Since emergency lighting is unlikely to be used on a daily or even weekly basis, there is nothing left to do but wait for something to happen. And if you do not regulate the current coming from the photovoltaic converters, you can recharge the battery. Here's a good time to use a charge regulator. It only takes four connections to combine the solar array, charge regulator and battery pack. One conductor should connect the positive terminal of the solar array to the positive input of the charge regulator, as shown in fig. 2. The negative output of the solar panel must be connected to the negative input of the regulator.
The positive and negative terminals of the charge regulator are connected to the positive and negative poles of the battery, respectively. These electrical connections are permanent, and it makes no sense to put any kind of switch in the circuit; if necessary, the charge regulator feeds the battery with charging current, provided that the sun is shining at this time. When the battery does not require full charging current (which is the case most often), the regulator provides a small current to keep the battery charged. The value of this feed current is determined by the value of the current-limiting resistor Rs in the regulator circuit. For this case, a half-watt carbon resistor of 22 ohms is suitable as Rs. Power failure sensor The emergency lighting circuit is monitored by a power failure sensor. The principle of operation of the sensor is quite simple, as can be easily seen from Fig. 3.
Alternating voltage is applied to the circuit through transformer T1, which lowers the mains voltage to 6 V. Then the rectified and smoothed voltage is used to control the relay RL1. The relay is on as long as there is AC voltage in the network. As soon as the voltage disappears, the relay turns off and its electrical contacts close the lamp supply circuit, thus turning on the emergency lighting. When the mains voltage is restored, the device automatically returns to its original state and is ready until the next power failure. The sensor circuit also includes control and indication elements. The indication is provided by a long-life incandescent bulb connected to the 6-volt winding of the transformer. The light indicates the presence of voltage in the network. But it cannot indicate the readiness of the battery or emergency lighting for operation. For this purpose, an opening non-latching button is placed in the gap of one of the output ends of the transformer. When you press it, the circuit breaks and the relay turns off. This activates the emergency lighting circuit. When the button is released, the circuit returns to its original state.
Power Failure Sensor Design The sensor circuit is quite simple and, therefore, can be structurally implemented in any way. For those who wish to make it using printed circuit wiring, the full-size layout of the board is shown in Fig. 4. The placement of parts is shown in fig. 5.
There is nothing special in the design; as usual, do not forget about polarity. After installation is complete, place the board in a plastic case. To test the finished device, it is connected to the network. Note the moment the relay is triggered. After that, connect the relay contacts to the emergency lighting circuit, and the job is done! Author: Byers T.
Traffic noise delays the growth of chicks
06.05.2024 Wireless speaker Samsung Music Frame HW-LS60D
06.05.2024 A New Way to Control and Manipulate Optical Signals
05.05.2024
▪ DC/DC converters NSD-10 and NSD-15 for board mounting ▪ Sweet sodas make people dumb ▪ Soda spoils the eyes and heart
▪ section of the site Factory technology at home. Article selection ▪ article Tricky mechanics. Popular expression ▪ article What is the height of the highest peak of the Earth? Detailed answer ▪ Article Courier. Job description ▪ article Sensors for burglar alarms. Encyclopedia of radio electronics and electrical engineering ▪ article Walking matches. Focus Secret
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page