Electronic phase switch is cheaper than an uninterruptible power supply, weighs less. This reason prompts many stability seekers to look for ways to acquire the device. In short - to ensure the stable operation of the equipment. There are devices of single-phase and three-phase networks. In each case, their requirements. We see the use of phase switches objects, where there is a possibility, the need for backup power supply.
Assigning the phase switch
The electronic phase switch will help to automatically transfer power from the lagging line to another. It happens, the voltage fails, the equipment is unable to work normally. Look, on most devices there are limits within which the product is capable. The information is indicated by technical data( instruction, passport), there are at least two values:
- The minimum voltage indicates how long the device is still able to take the power of the network to work.
- The maximum voltage indicates the upper limit at which the internal wiring does not burn.
The second limit is more important, most of the automatic phase switches react to it sharply. Implied response time. It is important to set the indicators correctly, avoiding false alarms. The phase switch of the standard version will allow regulating a number of parameters. Below are some.
Minimum voltage limit
Define the face below which the search for a solution will begin. Similarly, the upper mark is set separately. Understandably, the lower limit shows smaller values, the regions can overlap by 10–20 volts. We believe that the operation of the phase switch will become unstable, avoid to allow the situation. Just carefully set the upper and lower limits of the equipment according to the instructions.
Characterizes the interval after which the phase switch will try to transfer contacts to the previous power source. We say "try", not the fact that the line voltage will return to normal by this moment. Option helps saving. Suppose a generator is working, driving more expensive than feeding on a network. We would like to reduce the time. We know firmly: the shutdown is scheduled for an hour. There was a need to leave the house, the generator could not be cut down: it would freeze or, on the contrary, overheat. Determined by the time of year. We adjust the phase regulator to automatically return after an hour; a signal should be created stopping the generator engine. The implementation of the event is a separate topic.
Turn-on Time Sets the time interval after which the phase switch will try to cut the power after it completely disappears in the branches. Here the previous example is suitable, you can add: to form a signal as simple as using a 230 volt relay. The appearance of power on the line will serve as a reason to stop wasting fuel.
examples of countless, we give infinity. Phase switches are not uniform in purpose, capabilities, price, principle of operation.
Varieties of Phase Switches
Let's start with the immediate - 230 volts. The principle of operation of the phase switch is as follows:
- One contact main. Here comes the preferred phase.
What is different from others? Favorite phase that we trust. The question of choosing a narrowed: a personal problem. Just want the tension to be taken here. Spent, put here a thick vein of copper, reducing losses, the rest of the wiring is budget, the vein is thin, aluminum. The backup line will burn, powering the house for weeks, but it will last an hour or two. There is no desire to pay extra money loss. Chose the favorite copper phase, which frankly count on. Connect it to the main contact of the switch to avoid excesses.
- The second and third contacts are designed to initiate voltages of the secondary phases.
In an industrial network there are three phases, the voltage between adjacent ones is 400 volts. Relative to the ground - 230 volts. So eat houses. And start up on the possession of one phase. The voltage of 400 volts inside will not get. Suppose you have persuaded the supplier: “Brother, let's put the phase switch, suddenly you have power in one branch?”.The supplier says: "Konesna!"And why? Because if the load on the phases is asymmetrical, the transformer of the substation operates in an unprofitable mode, it may break. Therefore, he - the supplier - is ultimately profitable. Set on the phase switch three pieces.
- If the voltage of the preferred phase disappears, a transfer to the secondary occurs( at different intervals).
The device selects the one where the rating corresponds to the specified frames. There is no( complete loss of energy in phases) - the switch breaks the network. It is useful to generate a signal to turn on the backup generator. How? Is there a phase for it? It is necessary to start the secondary output or to collect garlands of standard phase switches. Find sold the finished product is impossible.
- Separately, we note: the devices have built-in spark suppression( otherwise, the life of the relay will dramatically decrease).
Sometimes the scheme is not needed, even vice versa - is excluded. It is often carried out with jumpers, which not everyone will find comfortable. It is necessary to carefully read the instructions on the subject of detail, for fear of reducing the shelf life of the equipment.
Above it was said: according to the settings, the phase switch will try to take its initial state after a certain time. Some work differently. In three-phase networks, the requirements are different. What is at home that would require incessant attention. Maximum fridge for drugs. In production, in a hospital, a three-phase phase switch is required. First, a misalignment can break equipment. One phase disappears, a short circuit happens, line failures, there is voltage, the rating is incorrect.
Immediately make a reservation, the automatic phase switch alone is powerless to perform the specified task, a number of problems solves:
- Manual control is convenient to avoid purchasing expensive sensors, control devices, controls. Suppose we know: turn off the lights, visit the basement, start the three-phase generator, and quietly wait for the return energy supply. Pre-manually set the phase switch, selecting the desired branch. After the end of the break in the supply of energy, hands back. Usually, this type of phase switch control blocks others. Be careful: if a pen is inserted, the remote control will surely refuse to work, the result will be deplorable. There are usually at least three positions: the first set of three phases, the second is the same plus a neutral, when nothing is guaranteed to go out. Contactors are used, mechanically excluding the simultaneous operation of lines, saving against overloads.
- The advanced phase switches described above will enable you to press a button. The electrical circuits are switched to the device to transfer branches on the signal. We do not claim that it will be possible to do it with the help of the London doorbell button( 50 rubles), specify when purchasing how phase switches are controlled.
- Electronic control is more complex. Here and there the line is plowed up with complex information of various kinds, the controller will have to be bought in addition compatible.
So, we see: the options vary greatly in price. Why not choose a simple manual! Some types of industrial equipment, as described above, are mortally afraid of the disappearance of one phase. One thing is to start the generator, another is constant monitoring. You will sit on the equipment, watch a voltmeter. That is why, in tandem with phase switches, there are often other relays, instruments. The tasks include tracking distortions on a par with the complete disappearance of the voltage.
. You can find similar devices with the following names:
- reversing switch;
- phase control relay;
- reversible switch;
- rocker switch;
- bypass breaker;
- phase breaker.
There is no consistent terminology, confusion reigns. The functions of the above instruments are the same: to determine the degree of suitability of the supply voltage, to choose among possible algorithms for eliminating the problem. Take the trouble to know the purpose of the phase switch, the possible combinations. Comparing, you can see: manual bypass switches, transfer the network from the main to the backup. There are no intermediate values. Bypass switch - manual phase switch.
To buy a phase changer or not to buy
Industrial equipment owners have no choice. The relay of the presence of phases can monitor the voltage, cut off the power, seeing the danger, monitor the correctness of the connection. If the alternation of lines is wrong, the setup is wrong, the device will not allow the load to start. Will save from breakage expensive equipment. Clearly, you will have to pay a lot, we need supply engineers to organize the operation correctly.
Ordinary citizens will be ashamed to call the price of phase switches excessive. See how much a simple uninterruptible power supply costs in the market, compare. The phase switch weighs less, is modest in size, and performs similar work. The question arises, where to get the right food.
Household is supplied with one phase, more is needed for control. Reassure the villagers: there is a complete set on the pole. Only if there are at least four wires. In the industry lived three. If the power circuit with isolated neutral.
It is pleasant to note: the design of some products is national. You can dial the options you need. ABB products are rich. So, the principle of the phase switches is concluded in a quick( instantaneous) change of the supply line for the load of the line that can withstand the specified nominal values. If there is no suitable, the voltage is cut down. With regard to specific methods of implementation, features - the nuances of the sea. Above described the most complex electronic devices, including elements of digital technology, simple and primitive manual knife switches.