Year1
- 1：
- 521
- 1：
- 1
- 2：
- 12
Transparent plastic case circuit breaker (hereinafter referred to as circuit breaker) is suitable for AC circuits with rated voltage of or and rated current of up to, as power distribution and overload and short-circuit protection of motors. It is also used for infrequent switching of circuits and infrequent starting of motors.
This product complies with standards.
2. Classification
The number of poles of circuit breakers is divided into single pole, two pole and three pole.
The purpose of the circuit breaker is to distribute electricity and protect the motor (only applicable to three poles
).
3. Environmental conditions for use
The altitude of the installation site does not exceed
Surrounding air temperature
The upper limit of the surrounding air temperature does not exceed +℃
The average value of the surrounding air temperature does not exceed +℃
The lower limit of the surrounding air temperature does not exceed ℃
Air conditions
The relative humidity of the atmosphere does not exceed the maximum ambient temperature of +°C. It can have a higher relative humidity at lower temperatures. For example, at +°C, the maximum relative humidity is and takes into account the temperature changes that occur on the surface of the crystal. Condensation
Installation conditions
Install in a place without impact, vibration, rain or snow, and the inclination with the vertical plane does not exceed.
Installation Category III
Contamination level.
It is true that the circuit breaker is mainly used for protection. Its protection is currently more commonly used as three-stage protection, which is overload protection, short-circuit short-delay, short-circuit long-delay. There are also some under-voltage, over-voltage and other protections. Function. It depends on the brand and model. Its opening and closing can be manual or electric. There are three installation methods: fixed type and drawer type. It can be divided into low voltage according to the size of the current and the level of the working voltage
Contactors are mainly used for industrial control. Most of the loads are motors. Of course, there are some heaters and dual power switching. The on and off of the contactor is achieved by controlling the coil voltage. According to the arc extinguishing method Different structures can be divided into vacuum contactors and ordinary contactors. According to different control voltages, they can be divided into DC contactors and AC contactors. Its main accessory is the auxiliary contact
Common faults and solutions
Contact Causes and treatment methods of unreliable contacts of contacts
Insecure contact of contacts will increase the contact resistance between dynamic and static contacts
Contactor (picture)
Cause the temperature of the contact surface to be too high , causing the surface contact to become point contact, or even non-conduction. The reasons for this failure include oil stains, lint, foreign matter on the contacts, long-term use, oxidation of the contact surface, defects, burrs or arc ablation. Metal shavings particles are formed, etc., and the moving parts are stuck.
The treatment method is: for oil stains, lint or foreign matter on the contacts, you can wipe them with cotton cloth dipped in alcohol or gasoline. , If it is silver or silver Base alloy contacts
Contactor (picture)
When the contact surface forms an oxide layer or is slightly burned or blackened under the action of arc, it generally does not affect the work. Alcohol, gasoline or carbon tetrachloride can be used Solution scrubbing. Even if the surface of the contact is burnt and uneven, you can only use a fine file to remove splashes or burrs around it. Do not file too much to avoid affecting the life of the contact.
For copper contacts, if the degree of burn is minor, you only need to use a fine file to repair the uneven areas. However, it is not allowed to polish with fine emery cloth to avoid quartz sand particles remaining between the contacts and unable to maintain the Good contact. If the burn is severe and the contact surface is low, the contact must be replaced with a new one.
If the moving part is stuck, it can be disassembled for inspection.
Maintenance and inspection Frequent or periodic inspection of the operation of the contactor
Contactor (picture)
Performing necessary maintenance is an important measure to ensure reliable operation and extend its life. When inspecting and repairing, disconnect the power supply first and follow the steps below.
, Appearance inspection to remove dust, use a cotton cloth dipped in a small amount of gasoline to wipe off the oil, then wipe dry with a cloth and tighten all the screws of the crimped wires to prevent them from loosening and falling off, causing the connection parts to heat up. []
, arc extinguishing cover maintenance) Remove the arc extinguishing cover, and use a brush to remove the falling objects or metal particles in the cover. If the arc extinguishing cover is found to be cracked, it should be replaced in time. ) For the grid arc extinguishing cover, attention should be paid to whether the grid is intact or whether it is burnt, deformed, severely loose, or has a changed position. If it is not easy to repair, it should be replaced.
, Contact system inspection) Check whether the dynamic and static contacts are aligned and whether the three phases are closed at the same time
Contactor (picture)
And adjust the contact spring to make the three phases consistent. ) Shake the phase-to-phase insulation resistance value. When using a megohmmeter, its phase-to-phase resistance should not be lower than megohms.
) When the contact wear exceeds the thickness, or is severely burned or welded off, new parts should be replaced. Slight burn damage or hairiness or blackening on the contact surface does not affect the use and can be left alone. If it affects the contact, you can use a small file to smooth it and polish it. ) After repairing or replacing contacts, attention should be paid to contact spacing and overtravel. Contact overtravel will affect the final pressure of the contact. ) Check whether the auxiliary contact action is flexible and whether the static contact is loose
, iron core maintenance
) Use cotton gauze dipped in gasoline to wipe the end face
Contactor (picture)
Remove oil stains or dust, etc.) Check whether all buffer parts are complete and in the correct position) whether the rivets are broken, resulting in loose ends of the iron core) whether the short-circuit ring is detached or broken, pay special attention to hidden cracks. If it is broken or causes serious noise, the short-circuit ring or iron core should be replaced) and check whether the electromagnet is well engaged and whether there is any misalignment.
, Maintenance of electromagnetic coil) The attraction coil of the AC contactor should be able to work reliably when the power supply voltage is the rated voltage of the coil. ) Check whether the electromagnetic coil is overheated. Coil overheating is reflected in the aging and discoloration of the outer surface. Coil overheating is generally caused by short circuit between turns. At this time, its resistance can be measured and compared with similar coils. If it cannot be repaired, it should be replaced. ) Are the leads and wipers open
Working conditions
Ambient air temperature The upper limit of the ambient air temperature + ℃ The lower limit of the ambient air temperature ℃ The average value of the ambient air temperature does not exceed + ℃.
Altitude The altitude of the installation site does not exceed.
Atmospheric conditions Atmospheric relative humidity does not exceed the monthly average maximum relative humidity of the wettest month when the ambient air temperature is +°C. Higher relative humidity can be achieved at lower temperatures. At the same time, the monthly average minimum temperature of that month +°C, taking into account condensation that occurs on the surface of the product due to temperature changes.
Pollution level The pollution level is level 1.
Technical parameters
Rated voltage The rated voltage on the nameplate of the contactor refers to the rated voltage on the main contact. The commonly used voltage levels are DC contactors, ,,, and other grades. AC contactor,,, and other grades. If a load is a three-phase induction motor, an AC contactor should be selected. Rated working voltage The rated working voltage is the same as the rated current. The rated current on the nameplate of the contactor refers to the rated current of the main contact. The commonly used current level is DC contactor,,,,,,. AC contactor,,,,,,,,,,. The above current means that the contactor is installed on an open control panel, and the contact operation does not exceed When working in a long-term working system, and the power supply continuity rate does not exceed that of open installation, the current is allowed to be increased ~ for cabinet installation, it is allowed to be increased ~. Those between the above situations can be increased or decreased as appropriate.
, Rated working current The rated working current of the main contact is determined by the rated working voltage, rated power, rated working system, usage category and shell protection type to ensure the normal operation of the contactor. The rated operating current of the auxiliary contact The rated operating current of the auxiliary contact is the auxiliary contact specified taking into account the rated operating voltage, rated operating frequency, usage category and electrical life
Maintenance methods for each component of the contactor
? Regular or Regularly checking the operation of the contactor and performing necessary maintenance are important measures to ensure reliable operation and extend its life. When inspecting and repairing, disconnect the power supply first and follow the steps below.
, Appearance inspection to remove dust, use a cotton cloth dipped in a small amount of gasoline to wipe off the oil, then wipe dry with a cloth and tighten all the screws of the crimped wires to prevent them from loosening and falling off, causing the connection parts to heat up.
, Contact system inspection) Check whether the dynamic and static contacts are aligned, whether the three phases are closed at the same time, and adjust the contact spring to make the three phases consistent. ) Shake the phase-to-phase insulation resistance value. When using a megohmmeter, its phase-to-phase resistance should not be lower than megohms. ) If the contact wear exceeds the thickness, or is severely burned or welded off, new parts should be replaced. Slight burns or hairiness or blackening of the contact surface do not affect the use, and it is not necessary to repair the arc extinguishing cover.) Remove the arc extinguishing cover and use a brush to remove the falling objects or metal particles in the cover. If the arc extinguishing cover is found to be cracked, it should be replaced in time. ) For the grid arc extinguishing cover, attention should be paid to whether the grid is intact or whether it is burnt, deformed, severely loose, or has a changed position. If it is not easy to repair, it should be replaced.
, Maintenance of electromagnetic coil) The attraction coil of the AC contactor should be able to work reliably when the power supply voltage is the rated voltage of the coil. ) Check whether the electromagnetic coil is overheated. Coil overheating is reflected in the aging and discoloration of the outer surface. Coil overheating is generally caused by short circuit between turns. At this time, its resistance can be measured and compared with similar coils. If it cannot be repaired, it should be replaced. ) Whether the leads and wiper parts are open
and maintenance of the iron core) Wipe the end face with cotton gauze dipped in gasoline to remove oil or dust, etc.) Check whether all buffer parts are complete and in the correct position) Whether the rivets are broken, causing iron The core end surface is loose) and whether the short-circuit ring has fallen off or broken. Pay special attention to hidden cracks. If it breaks or causes serious noise, the short-circuit ring or iron core should be replaced) Check whether the electromagnet is in good adhesion, is there any?
AC contactor
AC contactor
AC contactor is widely used For power switching and control circuits. It uses main contacts to open and close circuits and auxiliary contacts to execute control instructions. The main contact generally only has a normally open contact, while the auxiliary contact often has two pairs of contacts with normally open and normally closed functions. Small contactors are often used as intermediate relays in conjunction with the main circuit. The contacts of the AC contactor are made of silver-tungsten alloy and have good electrical conductivity
Basic introduction to the basic composition, working principle, classification of models using connection methods
Basic classification of electromagnetic AC contactor, permanent magnet AC contactor
Basic components
The AC contactor mainly consists of four parts that make up the electromagnetic system, including the attraction coil, the moving iron core and the static iron core contact system, including three sets of main contacts and one to two sets of normally open and normally open contacts. Close the auxiliary contact, which is connected with the moving iron core to interlock with each other and is an arc extinguishing device. Generally, AC contactors with larger capacities are equipped with arc extinguishing devices to quickly cut off the arc and avoid burning the insulating shell of the main contact. And attached
Working principle When the coil is energized, the static iron core generates electromagnetic attraction and pulls the moving iron core together. Since the contact system is linked to the moving iron core, the moving iron core drives the three moving contacts to run simultaneously. , the contacts are closed, thus turning on the power. When the coil is powered off, the suction force disappears and the linkage part of the moving iron core is separated by the reaction force of the spring, causing the main contact to disconnect and cutting off the power supply.
Use of connection method
Generally, a three-phase contactor has a total of one point, three inputs, three outputs, and two control points. The output and input correspond to each other and can be easily seen. If you want to add self-locking, you also need to connect a line from a terminal of the output point to the control point.
2. First of all, you should know the principle of AC contactor. It uses an external power source to apply to the coil to generate an electromagnetic field. When power is applied, the contact point is disconnected. After knowing the principle, you should figure out the contacts of the external power supply, which are the two contacts of the coil, usually at the bottom of the contactor, and on each side. The other inputs and outputs are generally on the upper part and can be identified at a glance. Also note the addition of
model classification
in electrical engineering. Contactor is an automatic switcher used to connect or disconnect AC and DC main circuits or large-capacity control circuits with loads. The main control object is electric motors. It is also used for other electric loads, such as electric heaters and welding machines. For lighting equipment, contactors can not only connect and cut off circuits, but also have low-voltage release protection. The contactor control capacity is large. Suitable for frequent operation
AC contactor. It is mainly composed of electromagnetic mechanism, contact system, arc extinguishing device, etc. Commonly used are,,, and other series.
DC contactors are generally used to control DC electrical equipment. DC current is passed through the coil. The action principle and structure of the DC contactor are basically the same as those of the AC contactor.
But now the contactor models have been reclassified. They are all series. . .
Class contactors are used to control non-inductive or micro-inductive circuits. Class contactors are used to control the starting and breaking of wound asynchronous motors, and contactors can be used to frequently control the starting and breaking of asynchronous motors
/> Basic classification AC contactors can be divided into three types: electromagnetic type, permanent magnet type and vacuum type.
Commonly used AC contactors, , , and imported , , and other series.
Electromagnetic AC contactor
Structure
The contactor is mainly composed of electromagnetic system, contact system, arc extinguishing system and other parts.
①Electromagnetic system The electromagnetic system includes the electromagnetic coil and the iron core, which is an important part of the contactor, relying on it to drive the closing and opening of the contacts. ②Contact system contacts are the execution part of the contactor, including main contacts and auxiliary contacts. The function of the main contact is to connect and break the main circuit and control larger currents, while the auxiliary contact is in the control circuit to meet the requirements of various control methods. ③Off
Working principle When the contactor electromagnetic coil is not energized, the reaction force of the spring and the self-weight of the armature core keep the main contact in the open position. When the electromagnetic coil is connected to the control voltage (usually the rated voltage) through the control loop, the electromagnetic force overcomes the reaction force of the spring and attracts the armature to the static core, driving the main contact to close, turning on the circuit, and the auxiliary contact moves accordingly.
Permanent magnet AC contactor
Structure
The contactor is mainly composed of drive system, contact system, arc extinguishing system and other parts.
① Drive system The drive system includes electronic modules, soft iron, and permanent magnets. It is an important part of the permanent magnet contactor and relies on it to drive the closing and opening of the contacts. ②Contact system contacts are the execution part of the contactor, including main contacts and auxiliary contacts. The function of the main contact is to connect and break the main circuit and control larger currents, while the auxiliary contact is in the control circuit to meet various control methods
Working principle Permanent magnet AC contactor uses magnetic poles Based on the principle of same-sex repulsion and opposite-sex attraction, a micro-power contactor is formed by replacing the traditional electromagnet drive mechanism with a permanent magnet drive mechanism. The permanent magnet with fixed polarity installed on the contactor linkage interacts with the variable polarity soft magnet solidified on the contactor base to achieve the purpose of attraction, retention and release. The part of the soft magnet, the solemn
Features The innovative technical feature of the permanent magnet AC contactor is to replace the traditional electromagnet drive mechanism with a permanent magnet drive mechanism, that is, a control device composed of permanent magnets and microelectronic modules. , replacing the electromagnetic device in traditional products, there is no operating current during operation, only weak signal current. The microelectronic module contains six basic partial source rectification power supply voltage real-time monitoring
①The closing and holding of the traditional contactor is achieved by energizing the closing coil to generate electromagnetic force to overcome the opening spring. Once the current becomes smaller and the electromagnetic force generated is not enough to overcome the reaction force of the spring, the contactor cannot maintain the closing state. Therefore, the closing of the traditional AC contactor must be maintained by continuous energization of the coil. This current From tens to thousands of mA. And forever
② Noiseless traditional AC contactor closing and maintenance relies on the coil to energize the silicon steel sheet to generate electromagnetic force, causing the dynamic and static silicon steel sheets to attract. When the grid voltage is insufficient or the surface of the dynamic and static silicon steel sheets is uneven or contains dust or foreign matter When waiting, noise will occur. The closing and holding of the permanent magnet AC contactor relies on the force of the permanent magnet, so there will be no noise.
③ No temperature rise Traditional contactors rely on the coil to generate sufficient electromagnetic force to maintain the attraction. The coil is composed of resistance and inductance. If current is passed through for a long time, it will inevitably generate heat. On the other hand, the magnet in the iron core The passage will also generate heat. These two types of heat work together in the contactor cavity, often causing the contactor coil to burn out. At the same time, the heat reduces the main contact capacity. The permanent magnet AC contactor relies on permanent
④ The contact does not vibrate. The holding of the traditional AC contactor is achieved by energizing the coil. The holding force is related to the current and magnetic gap. When the voltage changes between closing and opening, When the critical state of the gate fluctuates, the contactor is in a closed or open state, and will vibrate continuously, causing the contacts to be welded or burned, and the motor to burn out. The holding of the permanent magnet AC contactor relies entirely on the force of the permanent magnet. The holding is completed in one step, and the voltage
⑤ Long life and high reliability The life and reliability of the contactor are mainly determined by the life of the coil and contacts. . In traditional AC contactors, the coil and iron core will generate heat when it works. Especially when the voltage, current, and magnetic gap increase, it is easy to cause heat and burn the coil. However, there is no possibility of burning the coil in permanent magnet AC contactors. Contact ablation is mainly caused by arcs generated during opening and closing. And transmission
⑥ The permanent magnet magnetic circuit used by the anti-electromagnetic interference permanent magnet AC contactor is completely sealed, and will not be subject to external electromagnetic interference during use, nor will it cause electromagnetic interference to the outside world
⑦ The anti-shock control electronic module can control the set release voltage value, and can delay a certain period of time before sending out the reverse pulse current to achieve low voltage delayed release or power failure delayed release, so that the motor it controls is protected from grid voltage fluctuations. (shock power) and jump to stop, thereby maintaining the stability of the production system. Especially for enterprises with device-type continuous production, it can reduce the amount of electricity, steam, and natural gas used for venting and resuming production
Select maintenance
Select ① Select the corresponding category of contact according to the control object, number of operations, and usage category of the contactor device. ②Select according to the rated voltage of the line at the location of use. ③ Select the rated current of the main contact of the contactor according to the load capacity. ④ For the voltage level and current type of the attraction coil, the requirements of the control power supply should be considered. ⑤The capacity of the auxiliary contact should be selected according to the required number of interlocking circuits and the number of connections it is connected to
⑥For the connection and disconnection capabilities of the contactor, when selecting, attention should be paid to the loads in some usage categories, such as capacitors, Illuminators such as tungsten lamps have a large current value when turned on and a long on-off time, so there should be a margin when selecting. ⑦ Regarding the electrical life and mechanical life of the contactor, calculate the required electrical life based on the known average number of operations per hour and the service life of the machine. If it cannot meet the requirements,
Maintenance ① Inspection items during operation) Whether the passing load current is within the rated value of the contactor) Whether the opening and closing signal indication of the contactor is consistent with the circuit status) Whether the operating sound is normal, whether there is discharge sound due to poor contact) whether the electromagnetic coil is overheated, whether the electromagnet There is no abnormality in the short circuit ring. ) Is the arc extinguishing cover loose or damaged? Is the auxiliary contact burned?
② Maintenance When maintaining electrical equipment, the contactors should be maintained together.
)External maintenance, sweep external dust to check whether the fasteners are loose, especially the conductor connection part, to prevent loose contact and heat generation
)Contact system maintenance, check whether the positions of moving and static contacts are aligned, and whether the three Whether the phases are closed at the same time. If there is any problem, the contact spring should be adjusted to check the degree of contact wear. The wear depth should not exceed the contact point. If the contact is burned and falls off when welding is opened, it must be replaced in time. If the contact is slightly burned, it generally does not affect the use. Sandpaper is not allowed to be used when cleaning contacts. A shaping file should be used to measure the phase-to-phase insulated electrical conductors. The iron core part should be maintained and dusted, especially between the moving parts and the core suction contact surface. Check the tightening of the iron core. Loose cores will cause increased operating noise. If the core short-circuit ring falls off or breaks, it must be repaired in time.
) Electromagnetic coil maintenance quantity Check whether the coil insulation, resistance coil insulation is discolored or aged. The surface temperature of the coil should not exceed the temperature. Check the coil lead connection. If there is open welding or burning damage, it should be repaired in time.
) Maintenance of the arc extinguishing cover. Check whether the arc extinguishing cover is damaged. Check whether the position of the arc extinguishing cover is loose or changed. Remove metal particles and debris in the gaps of the arc extinguishing cover.
Working principle of vacuum AC contactor
The vacuum contactor uses vacuum as the arc extinguishing medium, and its main contact is sealed in a special vacuum arc extinguishing tube. When the operating coil is energized, the armature is attracted, and the contacts are closed under the action of the contact spring and the self-closing force of the vacuum tube. When the operating coil is powered off, the reaction force spring overcomes the self-closing force of the vacuum tube to release the armature and the contact is opened. When the contactor breaks the current, platinum scale formed by metal vapor will be formed in the contact gap, which affects the contact
Selection of AC contactor
The selection of AC contactor should be reasonable based on the type of load and working parameters. Select. The specific steps are as follows
Selecting the type of contactor AC contactors are generally divided into Category I, Category II, Category III and Category IV according to load type, which are recorded as, , and respectively. The control objects corresponding to Class I AC contactors are non-inductive or slightly inductive loads, such as incandescent lamps, resistance furnaces, etc. Class II AC contactors are used for starting and stopping winding asynchronous motors. The typical use of Class III AC contactors is the squirrel cage. Type asynchronous electric motor
?Select the rated parameters of the contactor
Determine the rated parameters of the contactor according to the controlled object and working parameters such as voltage, current, power, frequency and working system.
) The coil voltage of the contactor should generally be lower, so that the insulation requirements of the contactor can be reduced and it is safer to use. However, in order to facilitate and reduce equipment, it is often selected according to the actual grid voltage. ) The operating frequency of the motor is not high, such as compressors, water pumps, fans, air conditioners, punch machines, etc., the rated current of the contactor only needs to be greater than the rated current of the load. Contactor types can be selected,
Operation and use
According to the national standard "Low-voltage electromechanical contactors and motor starters for low-voltage switchgear and control equipment", AC contactors can be divided into four types of working systems according to working hours< br/>The eight-hour work system is the basic work system. The agreed heating current parameters of the contactor are determined according to this working system. Generally, contactors of various series specifications are suitable for the eight-hour working system. The contactor of this type of working system can reach thermal equilibrium when its main contact passes the rated current when it is closed, but it should be opened after eight hours.
Uninterrupted work system This type of work system is a long-term work system, which is a work system in which the main contacts remain closed and carry a stable current for more than eight hours (weeks or even years) without interrupting the current. When the contactor remains in working condition for a long time, it is easy for the contacts to oxidize and dust to accumulate. These factors will lead to the deterioration of heat dissipation conditions, reduction of phase-to-phase and phase-to-ground insulation, and prone to creepage and even short-term work
The main contact of the contactor under this type of working system remains closed for a time insufficient for the contactor to reach thermal equilibrium. The load period is separated by the no-load period, and the no-load period is sufficient for the contactor temperature to return to the initial temperature ( That is, the cooling medium temperature). The standard values of contactor energization time for short-time working system are,,, and.
Intermittent cycle work system Intermittent cycle work system is also a repeated short-time work system, which refers to a work system in which the closing and opening times of the contactor are too short to allow the contactor to reach thermal equilibrium. Obviously the main factor affecting the time life of this type of contactor is the cumulative number of operations. The main parameters describing the intermittent cycle working system are the energization duration rate and operating frequency. The standard value of the energization duration rate is,,,
Analysis of different requirements Different working systems put forward completely different requirements for AC contactors. When selecting The focus of consideration is naturally different. There are fewer restrictions when selecting contactors for eight-hour work system and short-time work system equipment. It only needs to be considered that the rated current of the contactor is greater than the actual working current. When the equipment is important, a little margin should be left. When selecting contactors for uninterrupted work equipment, the first step is to analyze AC contactor energy-saving technology
AC contactors are widely used in low-voltage circuits. They are safe to use, easy to control, large in volume and wide in industry. necessity. There are currently over 100 million large and medium-capacity AC contactors with rated currents and above commonly used in our country. The active power consumed by the operating electromagnetic system during suction and holding is in the range of ~ tens of thousands. Between one to several hundred fur. The consumption is
If the corresponding power-saving tech
WhatsApp
