【 Weak current College 】 electrical fire---electrical switchgear of fire-Power By 【 China power house network 】

In electric power transmission and distribution, electrical transmission and automatic control system, it is often necessary to use electric switch-on and isolated power supply. Electrical switch in power plants, substations, and mining. Transport enterprises and agriculture, and other units and departments have a wide range of applications, is energy production, transmission and distribution of applications, such as links in electrical equipment. An automatic switch of fire 1. fire risk is mainly used for the automatic switch and Protection Division. DC electrical equipment, low voltage power supply system, if improper selection, mistake, lack of maintenance, an institution failures, poor contact. Dephased or by setting the value too large to be protective equipment when you cannot overload such phenomena, motion will lose protection role in causing the damage, the electrical equipment and electrical equipment along with burning, explosion and other phenomena that may ignite combustibles, causing a fire. Furthermore, the auto switch general control over a range of overall electric power system, therefore, because the switch failure caused by the loss and disasters can be quite large. 2. fire precautions (1) automatic switch models should be based on the use of premises, rated current load, release rated current, long and short delay action current value size and other parameters to select, must meet safety requirements. (2) automatic switch should not be installed in flammable, affected by the earthquake, humidity, high temperature, more dust, but should be installed in the dry. Bright, easy to repair and construction, and should be equipped with an electrical cabinet. Box, the installation is complete, enable the former to ensure good contact with the magnet. (3) operator, release. Contact points and the rotating part is automatically switch easy failure, use 1/4 mechanical life, you must add lubricating oil, remove burrs ash to be filthy. Welding-contact and maintenance work, such as fastening screws. Second knife switch, tebi switch and down smoothly switch of fire 1. fire risk three switch is mainly used for lighting, heating, motor control and other small electrical appliances-current-in-control, because of its use of universality and extensive range of objects, their fire risk is relatively large. In the event of an overload, fever, insulation damage, the lack of running, institution failures caused by short circuit and electric shock and bad because of the knife-edge. Knife switch and conductor connect relaxation, local heating, electric arc and other phenomena, ranging from damaging electrical systems up and running, and the resulting fire power. 2. fire precautions (1) knife switch should be based on the rated current and rated voltage for rational use, is strictly prohibited overloading. Its rated current for the motor rated current of 2.5 times. When you install, you should choose dry and bright, and equipped with dedicated distribution box. Power pick on a static contact, switch required installed to dress form, but should ensure close knife, convenient and flexible action. In the course of using the switch on a regular basis to check and wire the edgy and knife-contact Department is in contact with good, switch plastic box, porcelain base. Handle such damage, etc. (2) the use of iron can switch should be reasonable selection switch models, is strictly prohibited to use long time overload. Guarantee of good steel earthing switch. Insert fuse damaged should be replaced in a timely manner. Do not use other conductors used instead of the melt. Mechanical interlocking device and do not cover damage. after adventure (3) down with switch selection should be based on motor capacity and work situation. In the fall with switch should be loaded before level can cut off the three-phase power control switch and fuse. Down with switch per month at least one time inspection and repair. To find contact bad, thickness and wear half or less, and there are cracks, loosening phenomenon, you should power be replaced and repaired. (4) wet sites should use pull cord switch. Storage of flammable, explosive, corrosive substance room should be switched on in the outdoor or suitable place, or the corresponding explosion-proof and corrosion-proof switch. (5) neutral grounding system, single-stage switch must be received in the line of fire that prevent a short circuit occurred in the battle ground fire. Three contactors of the fire risk of fire (1) it is necessary to (1) contactor contacts spring pressure is too small. Contact welding, body stuck, cores polar phenomena such as the accumulation of grease causes the contactor does not release the power of long-term continuity, extremely easy to short-circuit a fire caused by line, and may cause electric shock and other malignant personnel. (2) contactor power supply voltage is too high or too low, inconsistent with the actual coil parameters, operating frequency is too high, adverse environmental conditions (such as moist. High temperature and corrosive gases, etc), motion part stuck, exchange of core grievances or gap significantly phenomena such as overheating will cause coils, causing a fire or burning. (3) the reasons caused a short circuit between phases: reversible switching contactors of the chain is not reliable, error allows two different timing of contactor while running; contactor operation time synchronization; conversion process produces the arc; the dust buildup, parts contact damage inch. 2. fire precautions (1) contactor installation should check the nameplate and technical data on the coil is in line with the actual usage requirements. Check and adjust the contact as required by the operating parameters and enable the action very contact synchronization. Ensure that the active portion of the contactor action without delay. (2) pay attention to clean the iron core extreme surface rust inhibiting oil. Connection to prevent the screws, washers and other parts fall into the internal clearance caused stumped and short circuit. The contacts needed to guarantee a firm no loose. (3) use not connected before the main contact of the power to attract coil, numbers, time to check the contactor action really reliable. Reversible conversion of contactor may also consider adding machine chain organization to ensure reliable chain. (4) for contactor frequent and timely work characteristics, monthly maintenance a contactor parts, fastening the contacts, the timely replacement of damaged parts, ensure that the contacts clean innocent. (5) contactor should normally be installed in a dry, less dust control boxes and its ARC device cannot conceivably avoid damage. Four control relay of fire 1. fire hazard control relay itself fire risk and not too big, but because of its automatic control and power supply system has an important role, once the operator error or mechanical failure actions, the consequences will be very serious. 2. fire precautions (1) control relay in the selection, in addition to the coil voltage. Current should meet the requirements, you should consider the accused objects to delay time, tripping current multiplier, contact numbers, and other factors.(2) control relay to be installed in small tremors, less dust, dry places, on-site non-inflammable. Explosive substances exist. After installation you must check whether the secure portions of contacts, contact contact is good, there is no insulation damage, confirm that installation is correct before running. (3) as the control relay actions are frequent, back to this must be done monthly maintenance at least twice. In addition to routine inspection, the focus should check whether the contact points of contact, there is no good insulation ageing, time the necessity should measure the insulation resistance values. In addition you should also note keep dust-free control relay clean to ensure they work properly.