Quite often, even in modern houses and apartments, the voltage in electrical circuits and networks can jump within fairly large limits. Naturally, such jumps will adversely affect the operation of household appliances and their durability. To prevent such situations, a voltage monitoring relay is used. The reason for such jumps may be a wire break or sagging, as a result of which the phase wire touches the zero. Literally in a few seconds, even before the protection works, computers, refrigerators, TVs and other household appliances can burn out.
What is a voltage monitoring relay? This is a multi-pole device (from two to four poles), which is designed to automatically turn off and on various electrical devices (heaters, refrigerators, radios, etc.). For automatic control in voltage monitoring relays, specially programmed microprocessors and microcontrollers are used, which are also sensorstemperature, current strength, voltage, voltage drop, and are also responsible for the process of turning off the device and the time it takes to turn off.
It should be clarified that, according to the design and conditions of use, depending on the number of phases, a single-phase and three-phase voltage control relay is distinguished. Three-phase protects electrical devices from overloads and from the possibility of load drawdown in the event of an error in the phase sequence, measures the effective values of phase and linear voltages in electrical networks with an isolated or solidly grounded neutral, controls the switching device of the load power circuit (in particular, the coil of a magnetic starter). Both the three-phase voltage control relay and the single-phase device monitor the power contacts of the magnetic starter or contactor both before and after turning on and off the load, monitor the he alth and performance of these contacts. The device turns off in cases of burning or sticking of contacts. The voltage monitoring relay may turn on after a user-defined time after troubleshooting.
The relay works quite simply. Using the buttons on the case, you must set the threshold (maximum and minimum) voltage values at which the circuit will break. The default values are 170V and 240V. By default, the relay will trip after 0.02 seconds. This extreme speed of operation cuts off the voltage before the appliances are hit.and technique. However, the voltage monitoring relay does not protect against lightning strikes.
There are two types of such a relay: for one outlet and for the house in general. The latter are the most common. Devices differ in load and in permissible current strength.
When choosing and self-assembling a voltage monitoring relay, you should pay close attention to the installation instructions. By and large, the wiring diagrams are the same, however, depending on the manufacturer, some details may differ.
