The energy sales company is doing everything possible to ensure that consumers receive high-quality energy. However, a large number of consumers using one source leads to the fact that energy consumption is uneven. This causes a sharp or gradual drop in voltage. To minimize the consequences of consumer actions, an automatic phase switch (PF) is used.
Content
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Phase switch device
- Using the manual type
- Automatic control
- Directions for use and precautions
Phase switch device
It should be noted right away that the switch does not affect the quality of energy in any way; for this purpose, an uninterruptible power supply unit, generators, batteries, and the like are used. The PF itself only chooses from the three phases the one that is most suitable for work. The conclusion follows from this: the use of the switch is possible only if there are at least two phases. Where only one phase is connected, nothing will change from the installation of the PF.
The switches can be divided into two groups:
- manual control;
- automatic control.
The electric switch is installed after the meter, so if there is a single-phase meter, it will have to be changed to a three-phase one. The power consumption does not change, the tariff remains the same, therefore, the cost of installing a new the meter will be associated only with its cost and installation price, as well as with the supply of additional phases.
Using the manual type
A three- or four-position cam toggle switch can be used as a manual PF. The principle of operation of the manual phase switch is reduced to the alternating switching on of pairs of contacts.
They are available in two types:
- in the case;
- frameless.
The switch consists of a rotating shaft that houses one or more cams. There is a stopper for fixing the position. Multiple pairs of contacts are used:
- movable;
- motionless.
The moving contacts are spring-loaded to return to their original position. The contacts themselves are usually coated with a layer of silver that can withstand high temperatures. This is necessary so that when large currents are opened, the contacts do not burn or fail.
The switch works as follows: when the shaft rotates, the cam closes one pair of contacts through the insulating rods. Further rotation causes the first pair to open and the second to close. In some designs, there is a position where all contacts are open. This position is called "off" and is denoted "0".
In other designs, it is not the cam that moves the bar, but the notch. The position at which one of the pairs of contacts is closed is indicated by the number 1.2 and so on. As a rule, the circuit breaker shows the contact diagram and the sequence of their closing.
Automatic control
Enterprises produce a huge number of three-phase automatic phase changeover switches. What should you look for when buying? First of all, for the switching current. This is the maximum current that this device is capable of breaking. After all, switching occurs without removing the load. What current is used in the room can be determined by the machines that stand in front of the meter (if the meter has not been changed for a long time, then after it).
The second thing that will help you realize your preferences in customization is the way of indication. On this basis, devices can be divided into:
- LED;
- liquid crystal.
In the first case, the indication is made using LEDs, the color of the glow is different, but more often green. These are set at the input of each phase, thus indicating which phase is currently in use. The liquid crystal display allows, among other things, to monitor the actual voltage.
The automatic three-phase switch works as follows: all connected current sources are under constant control, the voltage value is measured. As soon as the readings of the main line go beyond the set values, the load transfer is transferred to the standby phase.
The monitoring of the main line continues, and after its readings return to normal, a reverse load transfer occurs. For switching the load, magnetic starters are used, they are also called phase switching relays.
Directions for use and precautions
Manual and automatic switches are slightly different in their purpose. If electrical appliances in the house are protected from strong voltage surges, and the disappearance of the current does not lead to serious consequences, then you can safely use a manual PF.
Such a device is much cheaper. It is more reliable, because it is guaranteed that it will not be able to connect two phases at once. By design, only one pair of contacts can be closed. Visible contact breaks also contribute to single-phase wiring. The latches will prevent spontaneous switching from occurring. It can switch a fairly powerful load.
The disadvantage is that the person himself is needed to switch. But worst of all, the load has no overvoltage protection. Even if there are people in the house, they will not be able to quickly de-energize the house or apartment, and the result may be a burned out electrical appliance.
Automatic switch completely takes control and decision on switching. A person can not always notice overvoltage, while an automatic machine does it with lightning speed. He also switches much faster than a person.
The disadvantages include high cost. However, a more serious drawback is that during a thunderstorm, the device may fail. Semiconductor parts that make up an electronic circuit are highly susceptible to electromagnetic interference. This can lead to malfunction of the entire structure.
It is dangerous to create an automatic switch yourself without proper knowledge of electrical engineering and electronics. This can be dangerous not only for electrical appliances and the network as a whole, but also for human life.
