What is an impulse relay and how does it work?

  • Dec 14, 2020
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Most modern devices are designed to simplify life, which is why many of them are so widely used by humans. Among such devices, an impulse relay is often found, which allows you to automate many processes. How it works and what is remarkable we will consider in this article.

Device

There is a wide variety of impulse relays on the market; due to technical and design differences, you can find different devices. But as an example, we will consider the most simple and practical for understanding the principle of operation (see. picture 1).

Figure: 1. Example of an impulse relay device
Figure: 1. Example of an impulse relay device

The simplest example of an impulse relay consists of the following elements:

  • Coil - made of a copper conductor wound on a non-magnetic base, for example, a frame made of PCB, electrical cardboard, etc. Designed to create an electromagnetic field that affects magnetic elements.
  • Core - is made of ferromagnetic materials that interact with the magnetic field of the coil. Designed to move and perform magnetic effects.
  • Relay contact system - consists of movable and fixed contacts designed for signal transmission.
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  • Resistive, capacitive and signal elements - are used to set the logic of the device and indicate the state.
  • Timer - sets the relay delay time interval, but is not present in all models, helps to significantly expand the functionality of the equipment.

Principle of operation

The principle of operation of the impulse relay is to move the contact group under the influence of the electromagnetic field of the coil pulling in the core. In this case, the device is controlled via push-button channels. One push of the button gives a short-term impulse to the control output, and the contacts go into a stable state - supply or disconnection of voltage, therefore it is also called bistable (two stable state). Unlike the same contactor, such a relay is controlled by one impulse supplied by a button or a self-resetting switch, hence the name impulse relay.

For example, consider the operation of a specific device model - RIO-1 (see. Figure 2):

Figure: 2. The principle of operation of the RIO-1 relay

This device contains two groups of contacts - power and control. Power contacts are represented by terminals 11, 14 and N, control terminals Y, Y1, Y2, it should be noted that in other modifications of impulse relays the marking and number of contacts will differ. Let's consider the purpose of each of the inputs in order:

  • 11 - designed to supply power to it from the electrical network;
  • 14 - used to output a phase from an impulse relay to a connected load;
  • N - terminal for connecting the neutral wire from the common bus;
  • Y - a universal input, when a control pulse is applied to which, the relay goes into the opposite state - from on to off and back;
  • Y1 - intended solely for switching the impulse device into the on state, that is, if the contacts are already closed, the relay will remain in the same position, has priority over input Y;
  • Y2 - transfers the impulse device to the disabled state, has priority over the other two outputs.

A distinctive feature of RIO-1 is the break of the power circuit only when the sinusoid of the alternating voltage crosses zero, which significantly increases the service life of the contact group. However, the response time differs by 0.3 s, which must be taken into account for the design of accurate electronic circuits. The operation of the impulse relay through the supply of signals to each input is well displayed on the timing diagram of the device (see Figure 3):

Figure: 3. Timing diagram RIO-1

As you can see in the figure above, the ways to enable and disable the impulse device are represented by four interaction periods:

  1. When the button is pressed and a pulse signal is applied to the Y input, the operating voltage will be removed from the power output until the second signal is applied to the Y input. This is the simplest way to control, for example, a lighting system.
  2. In the off state, pulse control is applied to input Y1, as a result of which an operating rating of 220V appears at output 14. If it is necessary to turn off the same lighting on site, it is enough to give a signal to Y and the power supply will stop.
  3. By applying a pulse signal to input Y1, the power circuit is closed - potential is removed from output 14. When potential Y2 is applied, the bistable relay will disconnect and the power circuit will open.
  4. During this period, switching on is performed by applying a signal to input Y. And by applying a pulse signal to Y2, the switch contacts are opened.

This logic of work allows you to implement a number of interesting solutions, both in domestic and industrial processes. That will ensure the priority of switching certain objects and electrical equipment located in them.

P.S. For even more complete information on the topic of impulse relays, you can visit the page of our website - https://www.asutpp.ru/impulsnoe-rele.html