Characteristics of automatic machines and OUZO
Automatic machines, or automatic cuts, is what came to replacement to normal traffic jams, i.e. to safety locks in the ceramic body where the fusing delay was overcurrent protection.
Unlike the stopper, the automatic machine - the reusable device, and functions of protection at it are separated. First, protection against overcurrents (short-circuit currents or KZ), secondly, protection against the overload, i.e. automatic machine mechanism
breaks off the loading chain at small exceeding of the working current of the automatic machine.
According to these functions, the automatic machine comprises two types of breakers. The magnetic high-speed breaker of protection against KZ with the system of arc extinction (time of reaction of millisecond) and the slow thermal breaker with the bimetallic plate (time of its reaction - from several seconds to several minutes, depending on loading current).
Classification of automatic machines
There are several standard characteristics of shutdown of automatic machines:
- A, B, C, D, E, K, L, Z. And – for disconnection of chains with big extent and for protection of electronic devices.
- B - for lighting networks.
- With - for lighting networks and electric units with moderate currents (overload capacities on current it is twice more, than at In).
- D – for chains with inductive loading and electric motors.
- K – for inductive loadings.
- Z – for electronic devices.
Classification of OUZO
Devices of protective shutdown protect people from defeat by electric current.
OUZO reacts to differential current, i.e. the difference of the currents flowing on the lead and return conductor. Differential current appears at touch of the person to the protected chain and the grounded subject. OUZO for protection of people get out to current 10-30 mA, fire OUZO - to current 300 mA. The last protects all system of wiring, and at the fire usually leakage currents arise earlier, than KZ currents.
The choice of OUZO is complicated by the fact that this more difficult device, than the automatic machine. For example, there are difavtomata – the devices combining in themselves the automatic machine and OUZO. Also are subdivided by OUZO as execution on electronic and electromechanical. Experience showed that it is better to use electromechanical OUZO. They are better protected from malfunctionings and from breakdowns.
Are divided by number of poles of OUZO on:
- 220 V, bipolar for chains;
- 380 Century, quadripolar for chains.
Under the terms of functioning on:
- The EXPERT - reacting only to alternating sinusoidal differential current.
- And - reacting both to alternating sinusoidal differential current, and to the direct pulsing differential current.
- In - reacting to alternating sinusoidal differential current, to the direct pulsing differential current and to direct differential current.
On availability of the delay on OUZO without delay of the general application and with the time delay like S. According to the current characteristic (difavtomata) on B, C, D. And, at last, on rated current.
It is necessary to know that if normal OUZO and the automatic machine stand consistently in one chain, then the automatic machine has to be on smaller current, than OUZO. Otherwise OUZO can be damaged since the automatic machine breaks off the loading chain with the delay.
In conclusion it is necessary to tell that it is necessary to choose structures of well-known companies: ABB, GE POWER, SIEMENS, LEGRAND and others, at least certified in USA. It is better to choose electromechanical OUZO since they it is much more reliable electronic. Instead of the tandem it is better to choose from OUZO and the automatic machine дифавтомат, it will make the design of the guard more compact and reliable. Current characteristics need to be chosen depending on the used wiring. Current of operation of automatic machines and difavtomat has to be less the most permissible currents of cables.
For copper three-wire cables it is possible to give the following these compliances of section of conductors of the cable in square millimeters and currents of automatic machines:
- 3х4 – 32;
- 3х6 – 40;
- 3х10 – 50;
- 3х16 – 63.
I hope that after reading of all material it will be simpler to you to understand design and creation of the electrical wiring.
History of creation of OUZO
The first device of protective shutdown (DPS) was patented by the German firm RWE in 1928 when the principle of current differential protection which was earlier applied to protection of generators, lines and transformers was applied to protection of the person against defeat by electric current.
In 1937 Schutzapparategesellschaft Paris & With. manufactured the first operating device on the basis of the differential transformer and the polarized relay which had sensitivity 0,01 A and high-speed performance of 0,1 pages. The same year by means of the volunteer (the employee of firm) testing of OUZO was carried out. The experiment ended safely, the device worked accurately, the volunteer had only light blow electric current, though refused participation in further experiences.
All next years, except for military and the first post-war, hard work on studying of action of electric current on the human body, to development of electroprotective equipment and improvement and implementation of OUZO was conducted.
In our country the problem of use of devices of protective shutdown for the first time arose in connection with electric and fire safety of school students about 20 years ago. During this period were developed and put in production of UZOSh (OUZO school) for the equipment of school buildings. It is interesting that OUZO of this kind is put in school buildings still though owing to outdated technologies these devices already not quite meet modern requirements of electric and fire safety.
Reconstruction of the Moscow hotel "USA" after the notorious fire which arose because of the most ordinary short circuit was other event which aggravated the OUZO installation problem. The matter is that at construction of this hotel complex the principles of power supply were broken. Carrying out installation of devices of protective shutdown with the purpose to ensure electro-and fire safety forced the management of hotel to plan several tragic cases which led to death of service personnel.
At that time similar installations were issued only for industrial application. It was entrusted to develop installation of protective shutdown for household assignment to one of the defense enterprises. But tragedies did not manage to prevent, and the fire which resulted from the short circuit in USA hotel led to the numerous victims. After the fire at recovery of the building works on the OUZO installation in each number were carried out. As domestic were made by OUZO in very short time and had shortcomings, gradually began to replace them with devices of SIEMENS (Germany).
By this time household OUZO also our electrotechnical enterprises began to think of the problem of production. So, the Gomel plant "Elektroapparatura" and the Stavropol electrotechnical plant "Signal" were developed and began to release household devices of protective shutdown. And since 1991-1992 mass implementation of devices of protective shutdown in housing construction, at least, in Moscow began.
In 1994 the standard "Power supply and electrical safety of mobile (inventory) buildings from metal or with the metal framework for street trade and consumer services of the population was adopted. Technical requirements". Same year there was the resolution of the government of Moscow on implementation of OUZO which ordered obligatory equipment of new buildings of Moscow devices of protective shutdown.
In 1996 there was the Letter of Head department of public service of the Ministry of Internal Affairs of the USAn Federation of 05.03.96 No. 20/2.1/516 "About use of the devices of protective shutdown (DPS)". And the Government of Moscow made one more decision on increase in reliability of power supply of all housing stock, irrespective of the year of construction. It is possible to tell that the legalized mass implementation of DPS in construction of housing from this point began.
Now OUZO scopes are already accurately painted, the number of the normative documents regulating technical parameters and requirements to application of OUZO in electric units of buildings works. Today OUZO is the obligatory element of any distribution board, these devices equipped without fail all mobile objects (inhabited lodges trailers on kempingovy platforms, the trade vans, vans of public catering, small temporary electric units of outside installation arranged on squares at time of festive festivities), hangars, garages.
Besides, OUZO is built in socket blocks or forks through which the electric tool or electrical household appliances operated in especially dangerous, wet, dusty with the carrying-out floors, etc., rooms are connected.
Insurance companies at assessment of the risk defining the insured sum surely consider availability on object of insurance OUZO and their technical condition.
Now it is the share of each resident of the developed countries on average in two to OUZO. Nevertheless tens of firms for many years steadily in significant amounts make these devices of the most different modifications, constantly improving their technical parameters.Top