Photo light for street lighting
Street lighting is gradually becoming more reliable and easier to maintain and manage. This is achieved through automation, which is continuously being improved. In addition, the use of modern developments provides savings, as in the case of using a photo relay for street lighting. Depending on where the light sensor will be used, it can ensure continuous operation of the lamp at night, or control the work of the lighting installation according to a specific program.
HOW THE PHOTO REVIEW WORKS
The photocell operation is based on the action of a light sensor. This device is an electronic detector that responds to changes in light. It can use gas discharge elements, photoresistors or photodiodes. When the light level drops below a certain value, the sensor closes the electrical contacts, thereby turning on the lighting. With an increase in illumination, contact opening occurs.
An important characteristic of the sensor photocell for street lighting - the threshold of sensitivity (also known as the threshold). Depending on the design of the device, the threshold can be constant (in the simplest models) or adjustable. In the latter case, it is possible to choose the best option to turn on and turn off the light according to specific requirements. For this, a switch or regulator is provided. The setting of the triggering parameters of the photorelay is made when it is first turned on, and can also be adjusted subsequently. In addition, contingency switches are provided for manual control of luminaires.
ADDITIONAL MANAGEMENT OPPORTUNITIES
In more complex models, it is possible to regulate the operation of the photocell with the help of a timer. That is, he will control the lighting according to a predetermined schedule - for one day, a week or a longer period. The design can be supplemented by a motion sensor. In this case, the light turns on when the sensor detects the approach of a person or vehicle. From the false operation connected with various noises, special protection is provided.Recently, photorelay models for street lighting have become popular, which can be programmed through a computer, that is, remotely. Taking into account the fact that there are various types of photorelays on the market, which differ in both parameters and setting options, it will not be difficult for you to choose the best option.
WHAT ARE THE PHOTO RELIEFS?
The photorelay for street lighting can be divided into several types.
Models with built-in light sensor. In such devices, the sensing element is a light sensor that is located inside a transparent sealed enclosure. The device is fully autonomous.
Models with built-in photo sensor and timer. Allow you to make a flexible device configuration, changing the mode of switching on the lighting depending on specific tasks.
Models with a portable photocell. Due to the fact that the electronic filling in them is collected in a separate module, isolated from the photosensitive element, the service life of this design is longer. The wiring diagram of the device in this case may be more flexible: the electronic unit is placed indoors, under protection from the adverse effects of the environment,and the sensor is taken out on the street.
WE CHOOSE CHARACTERISTICS
Choosing a photorelay, you need to carefully study its characteristics.
The main ones are as follows:
- Operating voltage: usually 220 V (50 Hz frequency), but there are models designed for 12 or 24 V; import models also use 127 and 110 V (when powered from a centralized power grid, installation of a power supply will be required); ultimately, it depends on what scheme your device is connected to.
- Maximum load current: from 6 to 16 A; the indicator allows you to judge what kind of lighting the photorelay is designed for; this parameter is important when used on large objects: the more powerful the lamps used, the higher the current must be; When lighting individual porches or suburban areas, you can select a device with small values.
- Threshold: usually from 5 to 50 lx (lux); In models with adjustable sensor sensitivity, the range of values is wider.
- Power consumption: indicated by two numbers that indicate the own power consumption when the device is triggered (from 2 to 5-10 W) and when it is operating in standby mode (in modern models, this value is within 0.1 to 1 W).
- Short-time delay: characterizes the protection of the photocell from false alarms; may vary in the range of 15-30 seconds.
- Degree of protection: shows the reliability of the design in terms of penetration into the shell of the device of foreign objects and water; denoted by indexes of the international classification of degrees of protection; photo relay that can be installed outdoors in the street, usually marked with an indexIP65; other common indicesIP44orIP40they say that the device should be placed in the room; outdoors, it is permissible to use them exclusively in a protective casing; A photocell with a remote photocell often indicates a higher degree of protection for a module with a sensor than for a block with electronic filling.
- The range of permissible operating temperatures: taking into account the large differences between winter and summer temperatures in our country, it is desirable that this range be as large as possible, for example, -20 - + 50 ° С
- Dimensions and weight: modern photocell is compact and small in size, however, they can vary significantly in these parameters, which may affect their subsequent installation.
INSTALLATION OF PHOTO RELEASE
Connecting photorelays can make it difficult for a number of reasons: the existing layout of lighting devices, limited access to controls, and stringent time limits for switching on lights. The connection circuit of the photo relay depends on the design of the device used. Often it is depicted on the instrument itself. And in the technical passport attached detailed instructions for connecting photocell. In general, the connection scheme is as follows.
Photorelay has several wires. Their color can be different, but most often they are marked with blue (or green), red and brown (or black) color, in some cases there is a letter designation:L- phase wire,N- wire zero,Load- wire load. The device itself is powered by a blue wire (N- “zero”). It is connected to the “zero” of the junction box, as is the load - the lighting lamps. Brown wire (L- "phase") is fed to the input phase. Red wire (Load- “switching phase”) is intended for connection to the phase with which the current flows to the lamps. If the power of the lamps connected to the photorelay exceeds its power (for example, when powering an extended street), the load is connected through a magnetic starter or contactor of the required power.
Photorelay with two (or pair) pins
Entering the phase is connected to the corresponding terminal on the photorelay housing. Similarly, connect the "zero". The load is applied to the corresponding pins for “zero” and phase.
The photorelay with two conclusions is intended for control of one lamp. So that it regulates the operation of several lamps, they are connected in a parallel circuit and connected as mentioned above.