The time delay relay is designed to regulate the sequence of operation of certain elements of the electrical circuit. Mostly such devices are used in devices, where you need to automatically perform a certain action after a set period of time.
General information about the device
A relay is a device, which works on the principle of the battery. According to the duration of the working mechanism can be daily, weekly, guards. Install these devices there, where chain control is required, which have small capacities. At the same time there is a complete isolation between control and controlled conductors. The relay is designed to control several circuits simultaneously, with one signal.
First, relays were used in long-distance telephone circuits. They served as an amplifier: duplicated the signal from one circuit to another and transmitted it by a chain reaction. The relay worked in the first computers, executed simple commands in logic circuits.
What is used in the relay electromagnetic field? It is a shock absorber, which slows down or completely de-energizes the movement, at sharp hit of the coil in the voltage environment. This property allows the relay to delay time: the time of connection of the armature to the voltage coil is slowed down.
Several variants of such devices
- Electronic. They are used more often than other species. Devices can control processes with a time delay of fractions of a second, with the duration of continuous operation for several thousand hours. The main advantages are small size, minimum electricity consumption, availability of various functional programs;
- With electromagnetic deceleration. A feature of such devices is the presence of direct current for operation. The principle of operation is to delay the operation of the device, with increasing fundamental magnetic current. To do this, an additional flow is created in the secondary winding, which prevents the increase of the main. Such devices are able to withstand the inclusion of 0,07 to 0,11 With, disconnect from 0,5 to 1,4;
- Pneumatic relay. It is able to provide exposure from 0,4 to 180 With. The device itself has a special mechanism - a pneumatic damper. To adjust the time, it is necessary to change the cross section of the air intake hole. This type of relay is mainly used on industrial machines, conveyors, where consistent control is required. They provide a large number of contacts, which can be transformed from a normally open state to a normally closed state. In such relays coils are easily replaced, this makes it possible to place several relays compactly on one device;
- With clock or anchor mechanism. Operation of the device is provided thanks to the established spring, which is wound under the electromagnet. When the scale is set for a certain time, the contacts are triggered, and the anchor mechanism begins to work;
- Motor relays. The device can operate from 10 seconds to several hours. In a complete set of such devices, included: synchronous motors, reducer, electromagnet for coupling and uncoupling the motor with gearbox and contacts.
- Contactor programmable relay. This type is used for communication of electric motors and lighting loads. For such contacts relays are made of silver alloy. The main disadvantage of this type is high noise at work. Such relays are used in lighting devices, electric motors, heating devices, condenser batteries thermal evaporators, fans, aquariums, refrigerators and incubators.
The use of time relays allows you to save on electricity consumption, since the light will turn on and off automatically, after a set period of time.
How the time delay relay works
Thanks to that, that an electric current with the help of conductors creates a magnetic field, the current state of the relay responds with inductors to all changes. The location of the magnetic field will depend on the shape of the conductor. If it is made at a right angle, then the field will be located in the same way, if in the form of a coil, then the magnetic field will be located along its entire length. The strength of the magnetic field directly depends on the voltage.
Relays have become popular, because they have proven all the effectiveness of use. They can control large and small voltages. The relay coil is able to pass through the particles of watts, while the contacts conduct hundreds of watts of load energy.
The principle of operation of the relay resembles a binary amplifier on and off. As practice shows, one relay coil can actuate several contacts of one device. These can be contacts of any combination. The device works with contacts of any kind: mercury, metal, magnetic reeds.
What is the delay relay?
If the device is a simple two-channel electromagnetic relay, then it is included:
- wire coil, which is wrapped around an iron soft core;
- iron anchor, which is designed to provide low resistance to magnetic flux;
- moving iron arrow;
- one or more contacts.
The anchor is hinged to the yoke and mechanically connected to one or more sets of contacts. The spring itself holds the anchor. It is installed as follows, that in the absence of current in the magnetic circuit an air gap is formed. In this mode, the device, one of the contacts is in the closed position, the other is in the open. Some types of devices have more contacts, it all depends on the features provided.
Upon receipt of electric current, there is a generation of a magnetic field, which allows you to activate the valve with the subsequent movement of the movable contact. This allows you to break or connect to fixed contacts. When the contacts are open, the contacts are connected and closed, with the exception of the opposite action. When the current is off, the armature returns to its original position and returns to the force, which is several times less magnetic, therefore, his position is normally relaxed. Most often, this force is provided by a spring, gravity is used only in industrial plants.
When current is applied to the coil, the diode passes through it and dissipates energy from the decaying magnetic field during deactivation. If this process does not start, then the components of the circuit will receive an energy surge, which will cause them to fail.
Delay relay with your own hands
To create a relay with a delay of switching off 220 No special electromechanical knowledge is required, it will be enough to have basic knowledge in physics and electromechanics. There is some guidance, which will help to assemble the relay yourself.
- To begin with it is necessary to take a nail of weaving, and kill it on a wooden surface, so, so that half of the nail remains above the surface.
- Further, you need to create an electromagnet. To do this, take a copper wire and wind it around the nail, gradually, turn by turn, from bottom to top. Fastening of the end of a wire becomes on a nail cap. For convenience of adjustment of size of a magnetic field it is recommended to leave for some centimeters on each end of a wire.
- The next step will be attaching the iron strip to the board. It should be bent in this way, so that one end is above the top of the nail.
- One of the electromagnet wires must be connected to the positive terminal of the battery. The other end is attached to the negative. In this way there will be a collision of a nail and an iron strip.
- You can now proceed to connect the device to the power supply. To do this, fix one of the clamps on the bottom of the nail, another on the railway strip. Further, the electromagnet turns on, and then, High-voltage.
- This relay is ideal for controlling lighting fixtures, turn off or turn on small devices. If you connect thyristors to the device and improve the timer, then it will last much longer.
- When the timer turns on, then you can set a specific time from a few seconds to several hours.
The use of circuits on the transistor is considered optimal for the time relay. Such relays are excellent for control of work of janitors on the car, turning lights on and off on the street, washing machine operation. Delay of switching on the 220V relay is an excellent option, which combines home amenities and excellent savings.