Time delay relay is designed to adjust the sequence of operation of certain elements of the electrical circuit. Basically, such devices are used in devices where it is necessary to automatically perform a certain action after a set period of time.
1 General device information
- 1.1 Several options for such devices
- 2 How the time delay relay works
- 3 What is the delay relay?
- 4 Delay relay do it yourself
General device information
A relay is a device that works like a battery. For the duration of the working mechanism can be daily, weekly, hourly. Install these devices where control of chains which possess small capacities is necessary. When this happens complete isolation between the control and guided conductors. The relay is directed to control simultaneously several circuits using a single signal.
Initially, relays were used in long-distance telephone circuits. They performed the function amplifier: duplicated the signal from one circuit to another and transmitted it through a chain reaction. The relay worked in the first computers, executed simple commands in logical circuits.
What is the relay used for? electromagnetic field? It is a shock absorber that slows down or completely de-energizes the movement, with a sharp hit of the coil in the medium voltage. This property allows the relay to delay time: the time of connecting the armature to the voltage coil slows down.
Several options for such devices
- Electronic. They are used more often than other species. Devices can monitor processes with a time lag of a fraction of a second, with uptime of several thousand hours. The main advantages are small size, minimum power consumption, the presence of a variety of functional programs;
- Electromagnetic slowdown. A feature of such devices is the presence of direct current to work. The principle of operation is to delay the operation of the device, with an increase in the main magnetic current. For this, an additional flow is created in the additional winding, which prevents the main flow from increasing. Such devices are capable of withstanding switching on from 0.07 to 0.11 s, tripping from 0.5 to 1.4 s;
- Pneumatic Delay Relay. It can provide shutter speeds from 0.4 to 180 s. 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. This type of relay is mainly used on industrial machines, conveyors where sequential control is necessary. They provide for the presence of a large number of contacts that can be converted 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 at once;
- With clock or anchor mechanism. The operation of the device is ensured by the installed spring, which winds up under the electromagnet. When a certain time is set on the scale, the contacts are triggered, and the anchor mechanism starts its work;
- Motor relays. The device can work from 10 seconds to several hours. The package of such devices include: synchronous engines, gearbox, electromagnet for coupling and disengaging the engine with the gearbox and contacts.
- Contactor programmed relay. This type is used for the communication of electric motors and lighting loads. For such relays, the contacts are made of silver alloy. The main disadvantage of this type is high noise at work. Such relays are used in devices for lighting, electric motors, heating devices, condensing batteries, heat evaporators, fans, aquariums, refrigerators and incubators.
Using the time relay 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
Due to the fact that the electric current with the help of conductors creates a magnetic field, the current state of the relay reacts with inductors to all changes. Magnetic field locations will depend on the shape of the conductor. If it is made at a right angle, then the field will be located 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 is directly dependent on the voltage.
Relays have become popular because they have proven their effectiveness in use. They can control large and small voltages. The relay coil is able to pass through a fraction of watts, while the contacts conduct hundreds of watts of load energy.
The principle of the relay resembles 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 includes:
- a wire coil that is wrapped around an iron soft core;
- iron anchor that is designed to provide low resistance to magnetic flux;
- movable iron arrow;
- one or more contacts.
The anchor is fastened by means of hinges with a yoke and mechanically connected with one or several sets of contacts. The anchor itself holds the spring. It is installed so that during the absence of current, a magnetic circuit is formed in the magnetic circuit. air gap. In this mode of the device, one of the contacts is in the closed position, the other is in the open. Some of the types of devices have a greater number of contacts, it all depends on the functions provided.
When an electric current arrives, a magnetic field is generated, which allows the reinforcement to be activated with the subsequent movement of the moving contact. This allows you to make breaks or connections with fixed contacts. When the contacts are open, the connection and closing of the contacts occur, when the action is turned off the opposite. When the current is turned off, the anchor occupies its original position and returns to the action of a force that is several times less magnetic, therefore its position is normally relaxed. Most often this force is provided by a spring, gravity is used only in industrial installations.
When a current is applied to a coil, a diode passes through it and dissipates energy from the decaying magnetic field during decontamination. If this process does not start, the components of the circuit will receive an energy surge, which will lead to their failure.
Delay relay do it yourself
To create a relay with a shutdown delay of 220 V, special electromechanical knowledge is not needed, it will be enough to have basic knowledge of physics and electromechanics. Exists certain leadershipwhich will help assemble the relay yourself.
- First you need to take a nail weave, and drive it into a wooden surface, so that half of the nail remained above the surface.
- Next, you need to create an electromagnet. For this purpose, copper wire is taken and wound around the nail, gradually, turn by turn, from bottom to top. Fastening the end of the wire is done on the head of the nail. For ease of adjustment of the magnetic field, it is recommended to leave a few centimeters at each end of the wire.
- The next step will be the attachment to the iron strip board. It must be bent in such a way that one of the ends is above the top of the nail.
- One of the wires of the electromagnet 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 contact between the nail and the iron strip.
- Now you can proceed to connect the device to power. To do this, you need to fix one of the clamps on the bottom of the nail, the other on the iron strip. Next, turn on the electromagnet, and then the voltage.
- Such a relay is ideal for controlling lighting devices, turning off or turning on small devices. If you add thyristors to the device and improve the timer, then it will last much longer.
- When the timer starts, you can set a specific time from a few seconds to a couple of hours.
For the time relay is considered optimal using transistor circuits. Such relays are great for monitoring the work of janitors on a car, turning the light on and off outside, working washing machine. The delay in switching on the 220V relay is a great option, combining household amenities and great savings.