Household appliances and other electrical appliances in the house, powered by a 220 network, are sensitive to voltage drops. In such cases, its combustion is not excluded. To prevent trouble, you can install a voltage relay (PH). In emergency situations, it will simply work to turn off the equipment and de-energize the network section.
RN appointment
Overvoltage protection relays are used in private, commercial and industrial facilities. The main functions of the device:
- protection of equipment from fluctuations in the network;
- equally effective work with single- and three-phase networks;
- protection of phases from breakage, sticking, skewing;
- blocking of incorrect operation of the phases.
RN is used in such areas and industries:
- Any electrical equipment that has increased requirements for the quality of networks.
- Industrial production in order to ensure the smooth operation of equipment, machines.
- Public organizations and institutions: supermarkets, hospitals, play areas, cinemas, computer rooms, etc.
The voltage monitoring relay is not a stabilizer. It does not contribute to alignment, but simply analyzes and interrupts the operation of the network at critical indicators of its voltage.
Device and principle of operation
The main components of the LV are a microcircuit and an electromagnetic relay, enclosed in a plastic case. The mechanism works according to the following principle:
- connects to the power supply;
- constantly reads her readings and controls them;
- with significant reductions or exceeding the norms, the microcircuit sends a relay signal;
- he disconnects household appliances or equipment from electricity. The response speed of the overvoltage relay is from 10 milliseconds.
After the PH works and turns off, it takes some time before the device again powers up the household appliances and puts them into operation. During this time, the relay checks the stability of the voltage indicators.
Most of the device models allow the master to independently set the thresholds for the lower and upper voltages.
The operating intervals of the controlling mechanism are 100-400 V. During severe storms and thunderstorms, these indicators can go off scale, the relay simply will not cope with the task at hand. Therefore, at the time of bad weather, it is better not to risk it and disconnect household appliances from the sockets.
Most relay models are not capable of replacing the input circuit breaker, since they do not have overcurrent protection.
Types and designs of LV
All overvoltage relays are divided into types:
- single-phase;
- three-phase.
Additionally, mechanisms are classified according to the method of installation. The buyer is offered the following device options:
- Plug-socket. On the one hand, the device has the form of a plug that is inserted into a socket. On the other hand, there are sockets for connecting household appliances. The equipment is powered, as it were, through an adapter. This type of device is designed to serve one piece of equipment or a small group. All voltage parameters are displayed on the board. The master can independently set their upper and lower values using the buttons.
- Extension. This is a box with 3-6 outlets familiar to most users. All household appliances connected to the extension cord are controlled by a relay, protected from voltage surges.
- Digital mechanism for DIN rail device. These are more powerful devices that are placed on a distribution board.Thus, the electrical contactor protects all appliances around the house. The main feature of such a relay is a very wide range of settings and a large number of modes independent from each other. For example, turn-on time and delay, relays for minimum and maximum voltages.
With the correct connection of the digital PH, the entire apartment or house is protected from sudden voltage surges.
Benefits of using RN
The convenience of connecting a voltage relay for a master is as follows:
- The device can be operated at various temperatures from -20 to +40 degrees.
- The master has the opportunity to choose a device according to his budget from a huge number of its modifications.
- Reliable protection of electricians and all equipment in the house from combustion or failure.
- The luminous flux does not change even during the operation of the LV.
- Installation of the device is accessible and understandable even for a novice master.
- The appearance of any of the devices does not spoil the design of the room.
RN freely excludes from the network diagram those areas that were damaged during a thunderstorm or emergency.
How to configure relay parameters
When installing and connecting a digital device to the switchboard, the master can independently set its operating parameters. Experts recommend setting the following values:
- autoreclosing time - 180 sec .;
- umin (minimum voltage) - 190 volts;
- umax (maximum) - 245 volts.
All parameters are set by turning the potentiometer.
More often, manufacturers put the following ranges for settings into the mechanism:
- time of automatic reclosing (AR) - 5-900 seconds (15 minutes);
- lower value for cut-off (Umin) 160-210 volts;
- the upper limit for disconnection (Umax) 230-280 volts.
When the potentiometer is turned, all changes in readings are shown on the digital display.
How to choose a voltage monitoring relay
To make the right choice when buying a vending machine, you need to be guided by the following criteria:
- Type and kind of device. The most expensive, but powerful - rack and pinion. The simplest and most affordable is a fork.
- Availability of auxiliary options, manual settings, auto adjustments. It is desirable that the device has a display.
- Overheating protection function. This parameter makes the relay more reliable.
- It is important that the PH is made of polycarbonate. This material ensures that the device is incombustible in the event of an emergency.
- When buying a single-phase mechanism, you need to determine the power of the relay. Household ones are equipped with power contacts of 100 A. Here it is desirable to increase the power indicator by 25% and, taking this into account, purchase an automatic machine.
- All three-phase LVs are designed for a current strength of 16 A.
- It is worth paying attention to the manufacturer of the device, the appearance of the device.
Before buying a relay controller, be sure to read the instructions for it. Always take a warranty card from the seller and check the integrity of the case, as well as the performance of the protective relay.
Before connecting the PH, it is necessary to mount a circuit breaker for emergency power cut-off.
