What is the state of the failure of the electrical switch to cause the danger that the machinery can

For example, the electrical switch contacts are burned and adhered due to high current, and the contacts cannot be disengaged.

It can't be stopped, and the front face of the node is generally welded together.

Faulty electrical switches pose a danger that the machinery cannot be shut down, and is in a state of (fault).

1. Fault status.

A fault state is a state in which a mechanical device (system) or component loses its specified function. The failure of the equipment, even if it is a partial failure, sometimes causes the shutdown of the entire equipment, and even the shutdown of the entire assembly line and the entire automated workshop, bringing economic losses to the enterprise. The impact of a failure on safety can have two consequences.

The occurrence of some faults has little impact on the safety functions involved and does not pose a major danger. For example, when the power source or a component of the machine fails, the machine is stopped and in a failsafe state. The occurrence of some faults will lead to a certain dangerous state.

For example, there is a danger that the machine cannot be shut down due to a faulty electrical switch; The fracture of the grinding wheel shaft will lead to the danger of the grinding wheel flying; Failure of the speed or pressure control system, the danger of losing control of the speed or pressure, etc.

Second, normal working condition.

In the case of the machine in good condition, in the normal operation of the machine to complete the predetermined function, there are various unavoidable but necessary motion elements to perform the predetermined function, and some may have harmful consequences. For example, the mutual movement of a large number of parts of different shapes, the cutting of tool blades, the lifting of heavy objects, the noise of mechanical operation, etc., there are risk factors that are not conducive to personal safety, such as collision, cutting, falling of heavy objects, and environmental degradation under the normal working condition of machinery. These certain functions that are dangerous when the machine is working properly are called dangerous machine functions.

3. Abnormal working conditions.

In the process of machine operation, unexpected conditions caused by various reasons (it may be the operation error of personnel, or it may be a sudden loss of power or interference from the outside world, etc.). For example, unexpected start-up, uncontrollable movement or speed change, signal failure due to external magnetic field interference, instantaneous strong wind causing the crane to overturn and fall to the ground, etc. The abnormal working condition of machinery often has no warning, which will directly lead to minor or serious accident hazards.

Fourth, non-working state.

When the machine stops running and is in a stationary state, under normal circumstances, the machinery is basically safe; However, it is not excluded that due to insufficient environmental illumination, the collision between personnel and mechanical overhanging structures will be caused; structural collapse; Slipping or overturning of outdoor machinery under the action of wind; Combustion of stacked flammable and explosive raw materials**, etc.

Fifth, the status of overhaul and maintenance.

The maintenance status refers to the state of the machine when the machine is maintained and repaired (including maintenance, repair, modification, renovation, inspection, condition monitoring and anti-corrosion lubrication, etc.). Although maintenance is generally carried out in a shutdown state, the particularity of its operation often forces maintenance personnel to adopt some unconventional practices. For example, climbing heights, drilling pits, short-circuiting safety devices, entering dangerous areas that are not allowed to be entered under normal operation, etc., make maintenance or repairs prone to hazards that do not exist in normal operation.

Pick D

When the electrical equipment inside the substation is overhauled, all safety measures shall be taken by (the unit is responsible); The dispatcher is only responsible for the correspondence between the safety measures and the equipment (maintenance status).

The most effective measure to ensure the personal safety of maintenance personnel is to ground the maintenance equipment. From a safety point of view, there must be a clear disconnection point in an equipment outage. The confirmation of the equipment or line without power should be based on the electroscope indication.

Flammable, explosive, humid and other objects that affect operation shall not be stacked near various electrical equipment such as switchboards, switches, and transformers.

Qualifications and Requirements for Electrical Operators:

1) Electrical work must be professionally trained, pass the examination, and hold an electrical operation certificate.

2) Electrical workers who have interrupted electrical work for more than six consecutive months for any reason must pass the re-examination before they can work.

3) Electrical personnel must strictly implement the national safety operation regulations.

4) Electrical staff must be strictly familiar with the relevant fire protection knowledge, be able to correctly use fire fighting appliances and equipment, and be familiar with the emergency rescue methods for personal electric shock.

5) The transformer, power distribution station and electrician class should formulate and improve the rules and regulations and the corresponding post responsibility system according to the actual situation of the post and the seasonal characteristics. Do a good job of prevention and safety inspections, and deal with problems in a timely manner.

6) The site should be equipped with safety equipment, protective equipment and fire-fighting equipment. And regular inspection tests.

7) The operation and maintenance of electrical equipment and lines in flammable and explosive places must be carried out in accordance with relevant national standards.

8) Electrical equipment must have reliable grounding (zero connection), lightning protection and anti-static facilities must be in good condition, and regularly tested.

Select D, and the others can't accurately indicate that there is no power.

d. Use a qualified test pen to prove that the electrical equipment has no voltage

1. The equipment that must be powered off at the work place (1) and the live equipment with a normal range of activities of the staff in the work is less than the safety distance (10kv safety distance is. (2) There is a live department behind or on both sides of the staff, and there is no reliable safety measures for the equipment. 2. The scope of power outage for line operation (1) The outgoing line problem and contact switch of the service line should be repaired.

2) It is possible to shudder the power supply back to all switches of the maintenance line.

When the electrical equipment inside the substation is overhauled, all safety measures shall be taken by (the unit is responsible); The dispatcher is only responsible for the correspondence between the safety measures and the equipment (maintenance status).

The most effective measure to ensure the personal safety of maintenance personnel is to ground the maintenance equipment. From a safety point of view, there must be a clear disconnection point in an equipment outage. The confirmation of the equipment or line without power should be based on the electroscope indication.

Flammable, explosive, damp and other objects that affect operation shall not be stacked near various electrical equipment such as switchboards, switches, transformers, etc.

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Dear, hello, glad to have your question when carrying out electrical equipment and repair work, what system must be disconnected, help you to find the following answers: when carrying out electrical equipment maintenance and repair work, when carrying out electrical equipment maintenance and repair work, the system must be disconnected.

What systems must be disconnected when electrical equipment and repair work are carried out.

Dear, hello lead, I am glad that your question is carried out when electrical equipment and repair work, what system must be disconnected, to help you find the following answers: to quietly excite the electrical equipment maintenance and repair repentance work, electrical equipment maintenance and repair work, the system must be disconnected.

When carrying out electrical equipment maintenance and repair work, the system must be disconnected when carrying out electrical equipment maintenance and repair work.

The word system is a transliteration of the English system, that is, several parts are interconnected and interact, and the whole with certain functions is formed by the chain of the tomb. Qian Xuesen, a well-known Chinese scholar, believes that a system is an organic whole with specific functions formed by the combination of several components that interact with each other and depend on each other, and this organic whole is a component of the larger system to which it belongs. Wang Sui.

1. The mains voltage is unstable: the working voltage range of the switching power supply of the general home computer is 170V 240V, and when the mains voltage is lower than 170V, the computer will automatically restart or shut down. Because we sometimes don't feel the fluctuation of the mains voltage, we mistakenly think that the computer will restart automatically for some reason.

Solution: For areas where the power supply is often unstable, we can purchase a UPS power supply or a wide switching power supply of 130 260V to ensure the stable operation of the computer.

2 Poor quality of the socket or power socket, poor contact:

3 Insufficient power or poor performance of the computer power supply: This situation is also relatively common, especially when we add new equipment to our host, such as replacing a high-end graphics card, adding a recorder, and adding a hard disk, it is easy to appear. When the host is working at full speed, such as running a large 3D game, burning at high speed, or preparing to read a disc, when it is just started, the dual hard disks copy the data, and the output may stop due to the power protection caused by the instantaneous power supply is insufficient, but because the load is reduced when the power supply stops output, the power supply starts again.

Because the recovery time after protection is very short, the performance given to us is that the host automatically restarts.

There is also a situation that the performance of the host switching power supply is poor, although the voltage is stable and within the normal allowable range, but because the harmonic content in the output power supply is too large, it will also cause the host to crash or restart frequently. In this case, it is normal for us to use a multimeter to test its voltage, and it is best to replace it with a good power supply.

4.Poor heat dissipation or failure of temperature measurement.

During the operation of the circuit breaker, when the following phenomena are found, the operation should be stopped immediately:

When the oil level is low due to a severe oil leak and the oil level is not visible.

The circuit breaker supports broken insulators or bursting bushings.

A discharge sound occurs in the circuit breaker.

Overheating and discoloration at the circuit breaker connection point.

The porcelain insulating surface of the circuit breaker is severely discharged.

After the fault is off, the circuit breaker is seriously sprayed with oil and smoke.

When stopping the operation of lead, measures should be taken to pour out the load as much as possible according to the importance of the load carried by the circuit breaker and the severity of the abnormal phenomenon.

The circuit breaker should stop running immediately when the following phenomena are found:

1. Serious oil leakage, there is no oil level in the oil mark pipe.

2.Support porcelain bottle breakage or casing burst.

3.The junction overheats and turns red or burns red.

4.The insulator is severely discharged.

The air chamber of the circuit breaker is severely leaking, signaling the operation of the lockout.

6.The hydraulic mechanism suddenly loses pressure to zero.

7.Smoke from the arc extinguishing chamber of the less oil circuit breaker or abnormal sound inside.

8.Vacuum circuit breaker vacuum damage.

1) Serious oil leakage, there is no oil level in the oil mark pipe.

The oil of the oil circuit breaker is used for arc extinguishing. When the oil circuit breaker is seriously leaking, if there is no oil in the circuit breaker, when the trip is serious, it will cause an arc short circuit.

2) Support the porcelain bottle to break or the casing to burst.

If the circuit breaker finds that the circuit is abnormal, the porcelain bottle will be broken or the casing will burst, which is also a power-off measure, if you find that the porcelain bottle is broken or the casing is burst when you use it, the circuit breaker should be replaced.

3) The connection turns red or burns red when it is overheated.

This situation is caused by a short circuit between the positive and negative electrodes, the circuit breaker will be detected and the power will be cut off immediately, such as uninterrupted power will be short-circuited and burned, the circuit breaker sometimes appears but the power is not cut off, if there is such a situation, the circuit breaker should be replaced or checked.

4) Severe discharge of insulators.

In this case, there is usually a problem with the insulator, resulting in a short circuit, and the circuit breaker detects that the power is immediately cut off.

5) The air chamber of SF6 circuit breaker is seriously leaking, and the operation lock-up signal is issued.

6) The hydraulic mechanism suddenly loses pressure to zero.

7) Smoke or abnormal sound inside the arc extinguisher of the less oil circuit breaker.

This situation can also be an oil leak, the main cause is that the oil level is insufficient, if so, it will cause an arc short circuit, detect and then lose power.

8) Vacuum circuit breaker vacuum damage.

In this case, the circuit breaker can only be replaced, and the vacuum part of the damaged circuit breaker is damaged and cannot be powered on, and the damage is detected and self-disconnected.

There is no specific circuit breaker, and usually the general-purpose low-voltage circuit device will automatically trip by itself, and there is no need to deal with the power outage.

When the circuit breaker is broken, when it can't be closed, you have to cut off the power and replace it with a new one, isn't it?