These include safety devices;switches;outlet;ammunition for light bulbs;Connectors (extension cords, luster connectors, plugs, etc.);household dimmers;junction boxes;cartridges for fluorescent lamps, etc.Power tools, disconnecting protective device (RCD), isolation transformers, electrified machines, etc.also referred to as installation devices.
Electrical Installation performed with varying degrees of protection from foreign bodies and water, the impact of environmental conditions on electrical safety.
Protection against foreign bodies provided housing or shell, and is denoted by Latin letters IP and two-digit number.His first number indicates protection against contact of live parts, and the second number against ingress of water, which has a detrimental effect on the operation.
In the first case: 0 - no protection;1 - protection against ingress of shell or shell of solids larger than 50 mm;2 - the size of solids of more than 12 mm;3 - 2,5 mm;4 the same, but no more than 1 mm;5 - against dust.
second digit: Oh - no security;1 - from water droplets falling vertically on the hull;2 - the same is tilted at an angle of 15 °;3 - by splashing water at an angle of 60 degrees, 4 - from circular spray;5 - against water jets;6, 7, 8 - better protection.
If the first and second level of protection is less than 2 installation devices, it is usually not indicated.
letters of the Russian alphabet in the marking point to the climatic conditions for which the product is intended: Y - areas with a temperate climate;UHL - temperate and cold climates;About - obscheklimaticheskie (for all climatic zones, except for the cold);B - all the climatic performance.
Under electrical distinguish five classes of protection: A - insulation ensures normal operation at rated voltage and its tolerances;01 - the same, but provides a separate frame ground wire, attached to the earthing clamps;7 However, grounding provides a special residential, located in the cable or cord;
II - double or reinforced insulation, grounding is not required;
III - chain of not more than 42 V. Protection
indicated in the technical documentation (passport) of the product.
SAFETY DEVICES, switches, connectors
fuse is a simple device for protecting electrical installations from large overloads and short circuits.In all cases, when the fuses can provide the required sensitivity of the protection, it is recommended to use them instead of circuit breakers.
The basic parameters of fuses are rated current, rated voltage and maximum breaking current.
principle of operation is simple fuse.His fuse when current flows through it is heated.During an overload or short circuit, it will burn.Wherein the circuit is broken.To insert the fuse when there was not a dangerous electric arc, which may damage the equipment or pose a danger to staff, it is placed in a porcelain tube.Fuse links made of lead and its alloys, zinc, aluminum, copper and silver.Fuse-lead and its alloys have a low melting point and have a thermal inertia due to the large specific heat capacity of these metals.Therefore, brief overload fuses are not cut off.On the other hand, due to the relatively high resistivity of these materials sectional fuse links for high currents and large obtained when a large amount of blown sprayed metal.Application of inserts - voltage up to 500 V.
By design fuses can be threaded type (bungy) or tubular.Fig.1 b shows the fuse PPT-10 fused WTF (insert tube made of porcelain) for 6 or 10 A for installations up to 250 V. The base 15 plastic is attached to the supporting structure with a screw.Inside the tube 14 (WTF) is dry quartz sand.The tube 14 is installed in the hole 13 of the lid 12 of the fuse.
For normal fuses, except tubes with a fusible link (Fig. 34, n) issued bungy machines (Fig. 34 c), which screwed into the base of the same, instead of traffic jams.With overload and short circuit in the line of machine disconnects the line your contacts.The circuit is restored by pressing the button 10. Button 11 serves to switch off the chain (instead of the switch).Are widely used machines AB-25 (Fig. 34 d).
A - plug with fuse-link;b - Fuse PPT-10 with porcelain insert tube;in - the mirror machine;g - breaker AB-25;1 - the case;2, 5- wiring;3 - inner contact;4 enclosure;6 threaded contact;7 fastening ring;8- cork;9 - fuse;10 - button recovery circuit;11 - the button off the circuit;12 - a cover of the fuse;13 - hole for the tube;14 - fuse;15 - base fuse
for domestic purposes issued switches with degree of protection IP 20 for indoor and outdoor electrical wiring.In addition to the hidden wiring may be used switches IP 54.
large range of design features breakers and switches, as well as their external and colors allows for their selection in accordance with the purpose, interior space, and also provides the convenience and reliability in operation.
for portable and floor (floor lamps) fixtures are often used switches and switches mounted directly on the wire.They can be lever, push button.If you directly on the lamp cord switch is sometimes used.Rocker switch mechanism often used as a wall.Best fit switches so that the switch is pressed the upper button, impact on the upper part of the button or lever is in its upper position (when used products lever).
switch with keyboard DRIVE
operating principle of the switch to a keyboard-driven illustrated in Fig.2a.When the key / in the position as shown on the left, a fixed 3 and 2 movable contacts are closed.To contact parted, it is necessary to press the button.Turning around the axis 01, the key takes on the position as shown on the right;while part 5, compressing the spring 4, will move to the right and turn the lever 6 about the axis 02 - open contact.Spring 4 fixes the position of the lever 6, and creates contact force.
general view of one embodiment of a keyboard switch with a drive is shown in Fig.2a.If you unscrew the screws 7, 8, remove the cover and then unscrew the screws 9, the unit comes off button (fig. 35 c).We'll see the lever 6 (it is shown separately on the right in Fig. 2d) and terminals 10 and 11 for connection of wires.One of them is connected to the fixed contact 3, and the other - with a support on which the swinging lever (Fig. 2, and this support is called the axis 02).Brackets 12, 13 spacer tabs
Fig.2. Push button A - operating principle;b - a general view;c, d, d - the device switches
and screws 14 are used to mount the switch.
If you remove the axle 01 (Fig. 2c), to release the 1 key and take it apart, you will see a spring 4 and part 5.
Switches with keyboards drive is now very common.
switch with slide and swivel design
switches of this type are of predominant importance in lighting networks and domestic installations and appliances.Kinematic scheme they can be very diverse (Fig. 3).
Rocker mechanism with a compression spring or tension spring are different from each other so that throwing of contact occur under tension or compression spring special.Type of this scheme - bladed.Fig.3, and shows a kinematic diagram of switches with a compression spring, which is actuated tumbler drive - crank 1. Breaking helical compression spring 2 is located inside the plastic parts on which the movable switching contact in the form of a U-shaped bridge 3 is made of brass.When enabled, the movable contact closes two fixed contacts, made of bronze and resilient in the ON position to ensure adequate contact compression.The unit working under the scheme, has three positions: disabled, passing through the neutral position of the handle - spring is compressed;included, after a quick throwing the movable contact to the fixed exposed decompress spring.The moment of opening and closing the switching contacts is independent of the speed of the drive throwing - arm or pressing force.Due to the elasticity of the fixed contacts having a comparatively small vibration.Release switches and switches of this type is greatly reduced.
Fig.3 (1).Switches to the slide and swivel designs: a - rocker mechanism with compression spring;b - the cam changeover mechanism with leaf spring;in - dvuhptechevoy swinging mechanism with a compression spring;g - Single Arm swinging mechanism with tension spring
Fig.3b shows the kinematic scheme switches to a cam mechanism and the drive rocker type.It modified end and flat spring contacts (and may be cylindrical). Closing and opening switching contacts occurs at a scooping arm-cam 4 because the plate spring 5 with the movable contact 6 is set at one of two positions - open or short circuit.Fig.3 (2), E represents a rotary mechanism with an eccentric device.It consists of a shaft 27 of square cross section, which is clamped and fixed in position by one or two flat (or spiral) springs 28. Hard planted cam 29 turning projection presses the leaf spring contact 30, pressing it against the fixed contact 31. When set toDrum rolling contact with the three points of contact and three fixed contacts of the switch are available for four positions.Fig.W, in the diagram of a two-arm rocker mechanism with compression spring.When you press the 10 reversible spring 14 together with stop ball 13 presses the lever 12, one side of which is welded a movable contact 11 which
Fig.3 (2).Switches to the slide and swivel designs: D - a mechanism for automatic pressure switch AB-2A;e - rotary cam mechanism
after moving the ball through the "dead point" above the axis of the lever is connected to or disconnected from the fixed contact.Fig.3 g shows a diagram of the switch to the Single Arm swinging mechanism and a tension spring, which works similar to a two-arm rocker mechanism.Here the tension spring 15 is attached to a special flip frame 16, a spring throws frame Ceramic silver or silver-movable contact 17 at one of the end positions, where there is its open or close with the fixed contact 18.
Pneumatic circuit arrangements convenient to consider the example of automaticswitch shown in Fig.3 (2). Here when pressing pressure is transmitted to the rubber membrane 22 closes the movable 20 and stationary contacts 21. Further, the air from the interior volume 24 is removed through micrometric screw 26 acting as a valve, and the spring 23 is compressed.Contacts remain closed only while the air through the orifice 25 does not fill the volume and straighten the membrane, which will give the opening spring pressure under the influence of which the contacts open.Such a switch may be used as a time switch which can be delayed by zero to three minutes.
FIXING DEVICES ELECTROADJUSTING
Depending on how open or closed wiring is meant attachment can be in many ways.In the first case (open wiring) provides a simple screwing mount device with two screws to the wooden sockets.The diameter of the outlet must always be greater than the diameter of the switch holder etc.Referring to Fig.4. into pieces and 1 socket screw screwed one flat, so-called "secret" head, which should be, as it were pushed into the socket.There are devices that do not require the sockets (fragment d).The role carries a plastic socket mounting base switch.
In the second case (concealed wiring) can also be used non-insulated device (fragment b).Their attachment to the outlet is the same as previously described, but the socket is screwed with not one but two screws 4, since the center of the rosette shall be opening 5 through which wires come out of the wall.To exit the wires in the wall socket must be inserted plastic sleeve 6.
Fig.4. Methods of fastening installation devices
If applied recessed fixtures, it is mounted in boxes or niches (fragments c, d, e, f).The brick and concrete walls walled box if wooden wall - drilled slot.The fireproof partitions used plastic mounting box.
In the construction of modern houses industrial methods for opening the boxes left in the manufacture of building structures.
Fig.37 shows the circuit breaker in 8 screwed to the bracket 7. In the box (Fig. 37, d) are made the holes in which the switch is in the (socket) entered brackets 9, and then tighten the screws 10.
can meet with reinforcementin a box, which is shown in Fig.37, d.In this case, the valve box is introduced through a portion where the hole is wider and then rotated to clamp 11 are under the projections.
Consider again the examples of devices for hidden electrical wiring, it is easy to see that the current device is attached, usually by means of lugs, as shown in Fig.4, e. For example, unscrewing the screw 13, remove the cover 14 socket and insert it in a niche (or box).To do this, first a little, unscrew the mounting bracket 12 of the screws 15, to release the spacer tabs 16. The distance between the ends of their decline and the socket (switch) is easy to enter the niche.Then it is necessary to screw the screws 15: spacer tabs move apart and firmly entrenched in a niche outlet.Finally, it should be screwed on the cover.
How to connect the outlet, Figure 5.
Fig.5. Connect the conductors to the outlet.7 conductors;2 - the clamping screw;3 - metal washer;4 - jaws;5 - holes for the screws that secure the socket to a plastic box;6 - screw hole cover
When the work related to the installation of installation devices, inevitably raises the question of the application of mounting boxes.
boxes used for the insulation of connections, tap the wires, cables, lighting and power networks, as well as for embedding and fixing them in switches, switches and sockets in the hidden wiring.For open wiring box is used, protected, dust-proof and splash-proof, and for hidden transactions - protected construction.
for branches and laid bare wire connections APN brands, SWP, APPV, ATPRF up to 2.5 mm2 used plastic boxes U419, U420, protected construction.Connections and branches cables of VRG, AVRG, AWG, ASRG, etc. ANRG. 2x4 mm2 cross-section up, laid open (without tubes) in potentially explosive atmospheres and outdoor plants produced in plastic boxes U409 dust-proof performance.For transactions carried out in wet and dusty environments cable with rubber or plastic insulation, and wiring in non-metallic pipes laid open with conductor cross-section up to 6 mm2 used plastic box CDF-73, CDF-74 in a splash-proof design.Branches of power and lighting lines made cables or wires, attached to a wire diameter of 8 mm, as well as special mechanical rope wires up to 10 mm2, produced in metal boxes U245, up to 35 mm2 - U246.