Relay 220V: purpose, principle of operation, types

To control various often very powerful circuits and mechanisms using low-current electrical signals or other factors of influence (heat, light, mechanics), special devices are used. They are different in power and design, but their meaning in one is to turn on or off the electrical circuit when the control signal comes in. Relay 220V also serves to protect the network.

What is an electrical relay?

In an electrical relay, one electrical signal controls another electrical signal. In this case, there is no place to change the parameters of the latter, but only its switching. Signals can be completely different in form, shape and power, but one thing is important: as soon as the current starts flowing in the control circuit, the commutation circuit works, connecting or disconnecting the load. When the control current disappears, the system returns to its original state.

An electrical relay is a kind of amplifier, if, for example, a weak signal commutes a strong one, and they are similar in shape and type of voltage. You can also consider such a device as a converter if the signals differ from each other in the form of a voltage.

Operating principle

It is clearly possible to consider the action of a relay using the electromagnetic example. Such a mechanism contains a winding with a core made of steel and a group of contacts that move freely, closing and breaking the chain. The control coil is supplied to the core coil. This current, according to the law of electromagnetic induction, creates in the core a magnetic field that attracts a contact group, and that closes or opens the electric circuit, depending on the type of relay.

Types of relays

The described devices are classified according to several parameters. For example, based on the type of voltage, the AC or DC relay is selected. Structurally, such devices differ from each other only in the type of the core, or rather, its material. For permanent relays, a core of electrical steel is characteristic, and there are two types:

1. Neutral.
2. Polarized.

The first differ from the second in that they can function in any direction of the current passing through the relay.

If we consider the type of the control signal and the corresponding design of the device, the latter are divided into:

• Electromagnetic, which contains an electric magnet, switching contacts.
• Solid state. The commutation circuit is assembled on thyristors.
• Thermal relays operating on the basis of a thermostat.
• Relay delay 220V.
• Optical, where the control signal is the light flux.

Relays of voltage control

To monitor electrical networks, or rather, voltage parameters, a relay 220V is designed. They are designed to protect household electrical appliances from sudden surges. The basis of such devices is a special microcontroller of rapid response. It monitors the level of voltage in the network. If for any reason there are voltage deviations greater or less than the permissible limit, a control signal is sent to the device, which disconnects the network from the consumers.

The threshold of operation of the relay 220V lies in the range of 170-250 volts. This is a generally accepted standard. And when the mains disconnection is carried out, the control of the voltage level in it continues. When the voltage returns to the permissible limits, the time delay system is activated, after which the power is returned to the devices.

Such devices are usually installed at the input of the circuit after the electric meter and the automatic safety switch. The power of the device should be with a margin to withstand voltage surges when the load circuit is broken.

Time delay relay 220V

The device, the sense of functioning of which is concluded in creating conditions where the devices of the electrical circuit operate in a certain sequence, is called a time relay. For example, if you want to create a load-on-load mode not instantly upon the arrival of a control signal, but after a specified period, a certain system is used. There are the following types of equipment:

• Time relay 220V electronic type. They can provide a temporary exposure within a fraction of a second and up to several thousand hours. They can be programmed. The energy consumption of such devices is negligible, and the dimensions are small.
• With the deceleration time on the electromagnet for DC power circuits. The circuit is based on two electromagnetic coils, in which magnetic fluxes are simultaneously directed in the opposite direction and thus weaken each other during the delayed response time.
• Devices where the response time is slowed by a pneumatic process. Exposure can be in the range 0.40-180.00 seconds. The delay of operation of the damper pneumatic is carried out by adjusting the air intake.
• Instruments on the anchor mechanism or clockwork.

Intermediate relay 220V

Such a device is considered an auxiliary device and is used in various automatic circuits, as well as in management. The purpose of the intermediate relay is the disconnect function in the contact circuits of the individual groups. It can also simultaneously turn on one circuit and turn off the other.

The switching circuits of the relay 220V are of two types:

1. By the principle of a shunt. In this case, all supply voltage is applied to the relay winding.
2. By serial type. Here the winding of the mechanism with the coil of the switch is connected in series.

In the relay circuit, depending on its design, up to three coil windings can be present.