There are many different tools that allow you to control voltage surges in the network. A three-phase voltage relay is used to control the power supply. If you select and connect the device correctly, the residents will be safe, and the property will be safe.
Application of devices
Three-phase monitoring relays are used to protect an electric motor from load in household and industrial areas. They help to work properly:
- air conditioning systems;
- refrigeration equipment;
- compressor installations.
The device is indispensable for any equipment with an ATS circuit and other devices operating on an electric motor load. Helps to avoid accidents.
Features of the device
There are different types of relays. They are produced taking into account the needs of problem networks, in which voltage interruptions and interference are possible. The devices are capable of delaying if a voltage drop occurs.
The three-phase voltage relay is installed in the panel on a special din-rail. It weighs very little and has simple settings.
Installation is carried out in parallel with the load, but the work does not depend on the power. At the outputs, the relay is equipped with closed and open groups of contacts that are independent of each other and switch loads up to 5A.
Principle of operation
The operation of the device is based on the principle of self-return. If an emergency occurs, the equipment is turned off. When a three-phase voltage is applied to the relay, it checks all parameters. If everything is normal, the built-in electromagnetic device turns on.
In the presence of malfunctions, the relay turns off, and after returning the parameters to normal, it turns on without delay.
During the entire period of operation, the device monitors the voltage level and switches off the load in the event of:
- loss of any phase;
- phase imbalance;
- phase sequence violations.
The device is designed to control the quality of electrical energy. It provides reliable protection of equipment from sudden voltage surges in the network.
Connection diagram and installation of the voltage relay
The instrument will perform its function regardless of position. But each model has its own wiring diagram. You can see it on the case.
For all devices, there are the same rules that are designed to control the process of connecting a relay to an electrical circuit.
Input contacts to the network are connected through a contactor or starter. Conductors of all phases are aligned with the terminals that are located on the top of the device. Elements are labeled like this:
- Phases in letters A, B and C.
- N - neutral wire terminal.
- 1,2,3 - bottom terminals.
First, from terminal 1, the conductor is connected to the output of the coil, which is located in the contactor. Terminal 3 is connected to any phase. The second output is connected to the neutral conductor of the three-phase network.
Power elements are connected as follows:
- Each phase that supplies current is connected to the input terminal of the contactor.
- The conductors are connected to the output terminals.
- To connect neutral conductors, a common zero bus is installed in the switchboard.
To ensure reliable contact, special tips are used.
RCD connection diagram
- Voltage relay 380 V 2-pole is not suitable for home. Use 4-pole counterparts. They connect 1 zero core and 3 phase ones. The circuit is complicated by the fact that each line is equipped with its own RCD device. It is important to choose the right wires. For a single-phase network, the standard VVG version is suitable, but for a 3-phase network, a fire-resistant VVGng is needed.
- General RCD for 3-phase network + counter. There is an electricity meter in the circuit. Group RCDs are located in the service system of individual lines. This scheme requires the installation of a large electrical panel with many wires and electrical appliances.
If the apartment or house has a large number of lighting and socket circuits, as well as various household appliances, it is advisable to install double protection with a common RCD.
General settings for a three-phase relay
- If the display is blinking, it means there is no voltage.
- The appearance of dashes indicates a violation of the phase sequence or the absence of one.
- If the display blinks for a long time, you should suspect that the contactor is not connected.
You can configure a three-phase voltage monitoring relay with two built-in buttons, they show triangles. They are located on the right side of the device: the upper button with a triangle up, and the lower one - down. To get the maximum shutdown limit, you need to press the top button. It lingers for a few seconds. After that, a number appears in the center screen with the display of the factory level. The button must be pressed until the desired value appears. After adjusting for ten minutes, the device will be automatically programmed.
How to set the re-trip time
On the right side of the display is a control button with a drawn clock. It must be pressed and held until the factory value appears. The time interval is 15 seconds. This means that after the voltage is normalized, the device will turn on the electricity again after this period of time.
Indicators can be reduced. A few clicks on the top or bottom button are enough to bring up the required parameters.
How to adjust phase imbalance
To adjust, press both triangular buttons at the same time. After that, you can see 50V on the display. This means that power will not be supplied to the network when the phase imbalance reaches this value. To decrease or increase a parameter, you need to set the time of one of the buttons.
Features of common types of voltage relays
Thanks to the voltage relay during power drops, the device will not burn out, the board will not melt, and the electric motor will not fail. The cost of the devices is considerable, but they pay off. It is better to prevent accidents than to buy new equipment.
There are several types of monitoring relays from different manufacturers on the market. They have the same principle of operation, although the design and the set of additional functions may differ.
Digital indication is installed in modern devices. It allows you to monitor the voltage level in three phases. There are also additional settings. With their help, they regulate the operation of the device and provide simplicity and ease of use.
A three-phase voltage control relay is an irreplaceable thing in the household. It is not difficult to connect and configure it. It will take no more than half an hour, after which all electrical devices will be protected from voltage surges.
