The apparatus is triggered upon the expiration of the designated time interval, called time switch - a device has found widespread use in electrical engineering, electrics, electronics. Thanks to its use in schematics manage to implement a more flexible management of various equipment and devices.
Depending on the design and principle of operation of the device can be arranged on different complexity performance electrical circuits.
Offer to find out what are the different kinds of timer, what is their specificity of work and application. Theoretical material is supplemented by practical guidelines and set-up time control device.
The content of the article:
The operating principle of the relay time
- Option # 1: electromagnetic devices
- Option # 2: pneumatic devices
- Option # 3: dial modification
- Option # 4: Electronic relay
- Setting the electro-mechanical analog switch
- Adjusting devices with a digital scale
- Connect the time relay in the control circuit
- Conclusions and useful videos on the topic
The operating principle of the relay time
Electronic devices are presented constructive variety, so consider the principle of the time switch device should be in view of each structural variation separately.
This looks like one of the many designs timer. In fact, the device resembles an ordinary switch, the effect of which, however, is tied to the time during the cycle
From the viewpoint of executable actions are used in practice, electromagnetic, pneumatic, electronic structures and devices at the clock mechanism.
Option # 1: electromagnetic devices
Devices that support the electromagnetic principle of operation, as a rule, are designed to work exclusively with the power supply circuit from DC.
electromagnetic relay design time REV-814 1 - unit fixed contacts; 2 - bracket; 3 - damper mechanism of copper; 4 - square; 5 - main circuit winding core; 6 - anchor; 7 - moving contacts anchor
Response time range is usually 0.07 - 0.11 seconds to enable and 0.5 - 1.4 seconds to turn off. The design of such time switch comprises two working windings, one of which represents a short-circuit in the form of copper rings.
When the main winding passes through the electric current on the rise of the magnetic flux. This current flow is formed a short-circuited winding, due to which the growth of the main winding magnetic flux is restricted.
As a result, a temporal characteristic of movement of the actuator armature or, in other words, the delay created by the inclusion of time.
The advanced design of electromagnetic relay type time. This model is supported by the unit switching four independent load channels. However weaker looks older models current device parameters (+)
If the current supply is stopped to the loop of the main winding, by the effect of the inductance, it remains active while the magnetic field is short-circuited winding. Accordingly, the relay is not switched off during this time.
Option # 2: pneumatic devices
Constructions on the basis of pneumatic systems - a sort of exclusive devices. These devices are equipped with special mechanics deceleration - pneumatic damper mechanism.
Adjust the dwell time by pneumatic relay can reduce or increase the flow cross section of the tube, through which the air supply. For this purpose, the design of pneumatic relays are provided with a set screw.
One of the most common designs of pneumatic devices. Simple enough reliable execution. Parameters switching current of 16 amps. As the switch is used mini-switch on two channels
Fitting Range pneumatic time delay relay is an average of 1 - 60 seconds. However, there are instances of overlapping, the range is almost doubled. However, in practice, there was a slight error (about 10%) in terms of operation of the accuracy of the stated values.
Option # 3: dial modification
The so-called clock time switches are widely used in electrical engineering. This kind of devices are often used in the construction of breakersDesigned for circuit protection voltage 500 - 10,000 volts. exposure range is 0.1 - 20 sec.
The principle of operation of watch models built on the work of the spring, vzvodimoy driven (anchor) of the electromagnet. Switching contact groups hour time switch is executed upon the elapsed time, the value of which has previously been installed on the instrument dial.
Representative enough of the ancient series of devices - time switch with clockwork. Meanwhile, this type of device has shown reliable trouble-free operation in a variety of settings
The speed of the device mechanism stroke is directly related to the current intensity flowing in the winding of the electromagnet. This factor allows you to configure the device for the performance of security functions. The feature of this protection is expressed in complete independence of the ambient temperature influence.
Option # 4: Electronic relay
The last few years, virtually wherever they can be used time switch, to replace outdated electromechanical models came electronic versions.
This type of device has a number of advantages:
- small size of the housing;
- High accuracy;
- convenient adjustment mechanism;
- a visual display of information.
Electronic versions are usually based on the digital pulse counters. Many modern appliances are built on high-performance microprocessors. Digital relay are normally designed for switching low-inductive or non-inductive loads.
Modern - digital relay designed to provide switching time. It attracted by the convenience of management and control, flexible configuration and appearance
digital type to set the time switch is enough to set the desired timing by using function keys, placed directly on the front panel of the case.
Setting is usually available in a wide range of time it allows you to include not only the seconds, minutes, hours, but days of the week. For example, consider the model of the weekly electronic relay - timer.
How does the weekly digital timer
Electronic timer with automatic on-off may well be used in control circuits different types of devices.
The so-called "week" time switch provides the switching functions in accordance with the prescribed period of time on a weekly basis. Such devices are used in systems "smart House".
For example, thanks to the device are opportunities:
- switch the lighting system at a given time;
- start or stop the process equipment;
- activate / deactivate alarm systems.
The device is small in size, has several function keys. Using the system keyboard, the user can easily configure it (program).
The user functionality of digital time relay - control panel with parameter setting keys. Plus LCD display, where all the information is displayed
The programming mode is activated by pressing and holding the button indicated by the symbol «P». Perform a system reset button helps the «Reset». Changing settings is done relays time minutes setting keys, hours, days, weeks, with the active programming mode.
Standard wiring diagram time switch provides installation of one of the two actions of control modes - manual or automatic. Ease digital type setting information relay provides a liquid crystal display.
Setting the electro-mechanical analog switch
industrial automation systems, and various household units are often equipped with electromechanical devices, the design of which provides for adjustment using potentiometers.
Electromechanical type countdown device with adjustable potentiometers parameters. There are various configurations of such devices, which makes it possible to use them in circuits of varying complexity
On the front panel of such devices is the potentiometer stem (or several rods) designed for rotation of the blade screwdriver. By circumferentially rod (rods) is applied to a marked scale setting values.
The slot on the rod by a screwdriver blade is a kind of pointer which changes its position when the stem is rotated. By setting this pointer in front of certain values of the marked scale achieved the desired parameter setting.
Multichannel device electron-mechanical type. Adjust it easy and simple by turning the potentiometer with a screwdriver. The front panel also has a LED state indication
Devices of this type (e.g. NTE8) Are widely used in the ventilation systems of control circuits, heating modules, artificial lighting devices.
Adjusting devices with a digital scale
Use of devices with mechanical adjustment functions can be illustrated by the timer domestic brands REV RitterIntended for inclusion in the network home outlet.
The so-called "rosette" switch for use in a domestic environment. Duration is usually limited to the daily range. This time is quite enough for domestic use
With help timer sockets It can be controlled within a predetermined range of time of almost any household appliances. To use this daily timer just turn the device into a power outlet and set up.
Setting is accompanied by the following actions:
- Raise all segments located on setup disk circumference.
- Lower only the segments that match the time setting.
- Rotate the adjustment dial to set the disc pointer to the current time.
For example, if the segments were deleted between the digits of the scale 18 and 20, after the relay will start counting time, the load will be included in 18 hours and 20 hours off.
In general, REV Ritter mechanical relay structure allows to arrange to 48 inclusions for a full 24 hours.
Modification of the "rosette" time relay: 1 - socket load connection; 2 - manual control; 3 - scale marked up to 24 hours; 4 - program segments; 5 - the index of the current time; 6 - plugging in home network (+)
However, the device supports the inclusion of an extra-curricular load. For this purpose there is a separate button on the side of the body. If the user activates the button, the load is connected directly to the network, regardless of the status relay contacts.
Connect the time relay in the control circuit
The device should be connected, taking into account the matching installation site conditions, which are stated in the data sheet of the device. Typically, installation involves installing the device at a vertical tolerances of deviation from the vertical by no more than 10º.
Temperature limits of space, where it is assumed installation and operation time relays typically do not exceed the range of -20 ° C to + 50 ° C.
humidity level in the device installation area should not exceed 80%. Circuitry, where a timer is set at the time of installation to be disconnected from the mains.
The classical relay circuit connection time, in this case, for the instrument, two channel switching with load. The same principle is connected devices on a different number of operating cycles (+)
Device of any design has traditionally product data, where designated connection circuit. Many electronic and mechanical timers and digital supplemented diagram labeled directly on the body and shows how and in what order to connect the timer relay.
Classic connection option is as follows:
- Connecting line voltage at the power terminals of the device.
- Phase line through the circuit breaker is connected to the input terminal of the relay load.
- The output relay load is connected directly to the load line phase.
In fact, the wiring diagram for the bulk of devices built on the principle of identity: the power connection on the device itself and the inclusion of the load through the group dial contacts.
Depending on the relay-type (single-phase, three-phase), and also from structural features, these contact groups may be several.
Simple version of the time switch can be made personally. Schemes are described in various samodelok this article.
Conclusions and useful videos on the topic
The video examines the possibility of using a modular device, where there are two independent switching on the device time. Scheme include two domestic appliances, setting their work in the time slots and other functions.
Of course, all of the existing modification time of the relay does not cover a modest review. To review the entire range of the instrument need to write a whole book. In fact, for different types of timers available directories, and to find the necessary information, it is always possible if desired.
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