How to work with portable electric lamps and the electric tool?
Portable electric lamps and the elektrifitsirovanyony tool in number of the neschastyony cases which came from them are high on the list. In otdelyyony industries where manual lamps and tools are in the crude or saturated with caustic couples rooms, the number of accidents at the raboyota with them makes up to 40-50% of total number электротравм.
The increased danger during the work with manual elekyotrichesky devices is caused, from one storoyona, by hard and long contact of the devices working with the body, and with another - exposure to their fast wear.
The severe concussions and pushes which are often found during the work with field instruments destroy their isolation and lead to fault to frame. Frequent movements and tension of figurative wires privoyodit to violation of their isolating cover, the obnazheyoniya of the current carrying vein and to weakening of contact, in the reyozultata of what bare conductors quite often concern the device body.
In some cases manual devices apply to works on the neighbourhood with big mass of the grounded metal (on steel structures, in boilers, etc.), at the naliyochiya of moisture, high temperature, the carrying-out floor when shock hazard is even more.
During the work with manual electric devices yavlyayotsya by basic reasons of accidents:
- availability of current carrying parts, closing kotoyory it is not provided by the design;
- application inappropriate, quickly изнашивающихся wires;
- lack of grounding.
In this regard fight against accidents of the dolzhyon to go through improvement existing and developments of new safe designs, figurative electrolamps and the electrified tool, through constant surveillance over them in the course of the ekspluayotation. But the most effective measure is the primeyoneniye of the lowered tension.
The persons having qualification are allowed to work with the electric tool groups II are not lower.
Before works with the electric tool have to be checked:
- tightening of screws, fastening of nodes and parts of the electric tool;
- turning by the tool spindle hand;
- condition of brushes and collector;
- condition of the wire, integrity of isolation, lack of breaks of veins;
- operability of grounding.
The person who was given the electric tool has no right to transfer him to other persons, to sort it or to repair, concern the cutting parts, to bring the instyorument in metal reservoirs or to conduct work at the height more than 2,5 m with ladders.
At interruption in supply of current during the operating time the electric tool has to be disconnected from the power supply network.
Manual portable lamps пользуется very wide range of persons. Portable lamps are often applied in the conditions of the increased shock hazard. Safety at the polyyozovaniye is ensured by portable lamps by use of poniyozhenny tension and creation of their safe konyostruktion.
Irrespective of the application lowered the napryazheyoniya it is necessary to use only the special pereyonosny lamp (fig. 1) which design isklyuchayot any possibility of touch to current carrying parts. The boss of such lamp becomes stronger in the special handle made of the warm and moisture resistant, isolating material of sufficient mechanical durability.
Current carrying parts of the boss and lamp are closed by the safety grid, and in crude places, in addition, the glass cap. The safety grid has to become stronger not on the boss, and on the lamyopa handle that it could not appear energized in case of damage of the boss. The way of fastening of the grid has to provide also impossibility of removal it without the special tool, preventing these access to the lamp of strangers.
To avoid the break or chafing of podvodyayoshchy wires, especially at the place of their input in the device handle, it is necessary to put on at charging of lamps the ruyokoyatka the rubber cup eliminating the bend of the provoyod on small radius, and as the bringing provoyod to apply hose wires of ShRPL.
For elimination of wrest of the bringing wires from under clips of the boss or the warning the oslableyoniya of contacts of the lamp on the wire in the handle the subhank of the insulating tape needs to make or to zavyayozyvat in this place the wire the node.
Portable lamps join network with помощью figurative reducing transformers of the low power of 50-100 W.
Plug adapters 12 and 36 in differ from the rozeyotok of 120-220 V, forks 12 and 36 would should not approach sockets - 220 Century.
The body of the reducing transformer and secondary winding have to be reliably grounded. Grounding of the body is made by the bolt, and accession to the zazemyoleniye - the privertyvaniye of the grounding wire the vinyotovy clip.
At works the transformer has to be in boilers, tanks, etc. outside. To bring the transformer in the drum of the boiler, in the fire chamber it is, etc. forbidden.
If during the operating time fault of the lamp, cord or transformer is found, it is necessary to take them to repare for the zayomena on operational.
The transformers feeding lamps on napryayozheny 36 V and below have to be protected from voltage of 220 V by safety locks with fusible inserts on the current close to rated (pasportnoyoma) current of the transformer. Protection has to выполняться also on the lines departing from tension of 12-36 Century.
Figurative electrolamps and transformers of the dolzhyona to be checked concerning their operability for otsutyostvy faults to frame, integrity of the grounding wire, operability of isolation of the wire, lack of the bared current carrying parts and for compliance to work usloyoviya.
Figurative transformers have also to проверяться by measurement by insulation resistance megger between windings.
Work with the electrified instyorument (drills, vibrators and so forth) proiskhoyodit in even more adverse conditions, than work with manual lamps. Strong shock influences, koyotory the tool in work is exposed, destroy isolation of its winding, and the body of the tool okayozyvatsya often energized. The worker, being in the dliyotelny and hard contact with the tool body, is affected by current.
If the body of manual portable lamps it is possible выполнять from the isolating material, then for instruyoment it is usually impossible as it is difficult to podoyobrat such insulating material which would vyyoderzhat the shock load of the tool. Besides, isolation would worsen refrigerating conditions of the winding and reduced the rated power of the tool.
To number of the reasons causing accidents during the work with the electrified tool otyonositsya: exposure of veins of the bringing wires, the pereyotiraniye of isolation of the wire on the bend (especially at the vvoyod), wrest of wires from clips and breakdown of the izolyayotion on the body.
Safety of work with the electric tool dostiyogatsya by application of the corresponding safe konyostruktion of the tool, grounding of the body, ponizheyoniy tension and periodic control.
Have to be provided in the design of the electrified tool:
- unavailability of current carrying parts;
- reliable isolation of current carrying parts of the instruyoment which would resist not only the vozdeystyoviya of the environment, but also to those pushes and blows by which its work is followed;
- performance of handles, chest emphasis on the vozyomozhnost from the isolating material or the metal covered with the insulation layer;
- availability of persistent rings or hoods, prepyatyostvuyushchy to touch to metal parts of the inyostrument (if handles or the chest emphasis of the vypolneyona from insulating material);
- shutdown on all poles at disconnection of the electric circuit by means of the switch which is built in the instruyoment; the control of the switch proizvoyoditsya without change of position of hands of the worker;
- application of hose wires of ShRPS and KRPT as the bringing wires;
- impossibility of the break, chafing or natyayozheniye of wires.
If the tool is intended for voltage over 36 V, then in addition to the listed trebovayoniya availability on the clip body is necessary for grounding and obligatory accession to network through the speyotsialny plug and socket connector with grounding konyotakty.
For the three-phase current such plug has 4 slots instead of the 3rd. Additional forks and slots provide connection of grounding at turning on of the tool.
The design of the plug and socket connector has to preyodusmatrivat grounding of the body of the tool before it appears energized, and removal the zazemleyoniya after working wires are disconnected.
In especially dangerous rooms and also in boilers, tanks, metal designs tension for the tool should not exceed 36 V.V rooms with the increased danger tension also should not exceed 36 Century.
At impossibility to ensure functioning of the elektroinstyorument for 36 V the device with tension to 220 V, but with obligatory use of protective equipment (gloves) and reliable zazemleyoniy the electric tool body is allowed.
The lowered tension necessary for the power supply of portable lamps and the electrified tool, it is possible to receive from the reducing transformer. Application for this purpose of autotransformers or additional resistance in any measure does not create necessary safety.
The figurative step-down CU transformers released with the rated power of 1,5 and 2,5 kW were widely adopted, with tension of the primary winding 380/220 of V. Vtorichyonaya the winding has the unsolderings allowing to receive the secondary voltage 220, 36, 12 V. Eto gives the chance to use the transformer of the same type for the power supply of the consumers having the distinguished rated voltage.
Transformers join network the clips located on the isolating contact boards. The same clips switch from the star to the triangle when it is provided. Contact boards are strengthened on walls of the casing and protected from splashes by folding hoods. The transformer zazemyolyatsya by means of 2 clips placed on casing walls on one from the lowest and vysyoshy tension.
The order of storage, vyyodacha and their survey is of great importance for safety during the works with portable elekyotrichesky lamps and the electrified instruyoment. As a rule, they have to be stored in the tool storeroom and be under nadzoyory qualified personnel.
Periodically field instruments and transformayotor to them need to be examined and tested. Peyored each delivery the tool is also in details osmatyorivat.
Except definition of suitability to work, survey aims to find out reliability of protection of tokoveduyoshchy parts, operability of the bringing wires, care of connections, grounding availability and so forth.
Irrespective of category of the room and also out of it, operation of the elektroinstruyoment energized of 220 V in the presence of the protective actuator providing remote upravleyony and automatic instant disconnection from network of the electric tool in case of its fault to frame or break of the grounding wire is allowed.
The schemes of actuators for avtomayotichesky protection against defeat by current and distantsionyony control of the electric tool developed by N.I. Orlov are provided on fig. 2 (the All-USAn Research Institute Stroydormash).
In the scheme (fig. 2, a) as the linear kontaktoyor used the contactor with the coil fed by postoyoyanny current of 27 V.
Engine management is exercised puyoty turning on of the double-band B1 switch and the mikroyovyklyuchatel of B2.
At turning on of the B1 switch the chain is created: через the reducing transformer T on the AF rectifier from the rectifier to the starting IS relay and on the electric motor D body.
At turning on of the B2 microswitch the IS relay works (the chain from rectifier minus via the fourth cable core, the throttle of Dr, the winding of the electric motor D, resistance of r1, r2, r3 and the starting IS relay to rectifier plus).
The IS relay closes normally open контакт and creates the chain for inclusion of the linear kontakyotor of JI.
Tension moves on the engine D.
Shutdown of the engine is carried out by switching off of the B2 microswitch (the direct-current circuit, the IS relay and the contactor L is broken off).
Protection at breakdown of one of phases on the body. The relay of protection of RZ is switched on through C1 kondensayotor between the origin of the star of resistance and the body of the tool.
At breakdown of one of phases will go to the elektroinstruyoment body, alternating current on the 4th vein кабеля through RZ, the C1 condenser and the origin of the star of resistance to the 2nd other phases.
The relay of protection of RZ will work, will open the noryomalno closed contact and will connect the feed circuit of the coil to the AF rectifier, than will deenergize kayotushka of the starting relay and the contactor L.
The initial scheme of the relay of protection will be recovered at disconnection of contacts of the B1 switch.
Control of operability of protection when receiving the electric tool is exercised by K. Soproyotivleniye's button rk in the chain of the button limits current size via the protection relay up to the size, safe for the person.
The scheme provides constant control for целостью the neutral wire as at break of posledyony the IS relay which contact will be switched off by the contactor L will be deenergized.
The protection relay reacts also to reduction of the soyoprotivleniye of isolation of phases concerning the body.
In fig. 2, as the linear contactor применен the magnetic actuator with the alternating current coil for 220 Century.
In this scheme at short circuit of normally open contact of the IS relay the linear contactor L (the magnetic actuator) directly from network of 220 Century includes. For the rest action of this scheme is similar to the first scheme.Top