中文How to choose a suitable AC contactor
Selection
Selection of AC contactor, the type of load and the reasonable selection of working parameters. Concrete into the following steps:
1 type of contactor
AC contactor is divided into one class, two class, three class and four class according to the load type, denoted as AC4, AC3, AC2 and AC1 respectively. The control object of a type of AC contactor is non sense or micro load, such as incandescent lamp, electric resistance furnace, etc. the two type of AC contactor is used for starting and stopping of winding induction motor. The typical application of three kinds of AC contactor is the operation and operation of squirrel cage induction motor.
2 selection of the rated parameters of the contactor
According to the controlled object and working parameters such as voltage, current, power, frequency and working system, etc..
1) the coil voltage of the contactor, generally should be lower for good, so that the insulation requirements can be reduced, the use of the more safe. But in order to facilitate and reduce the equipment, often according to the actual power grid voltage.
2) motor operating frequency is not high, such as compressor, water pump, fan, air conditioning, punch, etc., contactor rated current is greater than the rated current. Contactor type can choose CJ20, CJl0, etc..
3) of the heavy task type motor, such as machine main motor, lifting equipment, winches, crushing machine, such as. The average operation frequencies more than 100 times / min, running to the starting point, is the reverse brake, reverse connect brake state, can choose CJl0Z, CJl2 type contactor. In order to ensure the electric life, the contactor can be used for reducing the capacity. Selection, the contactor rated current greater than the motor rated current.
4) of severe motor tasks, such as printing machine, boring machine etc., the operating frequency is very high, up to 600 ~ 12000 times / h, often running for starting, reverse connect braking, reverse state, contactor roughly can be according to the electrical life and starting current selection, the contactor type selection and CJl2 CJl0Z etc..
5) in an AC circuit of capacitor input from the power grid or removed from the grid and selecting contactors switching surge current of capacitor should be considered. Generally, the rated current of the contactor can be selected according to the rated current of the capacitor 1.5 times, the model selection of CJ10, CJ20, etc..
6) in the control of the transformer, the size of the surge current should be considered. For example, AC arc welding, resistance welding, etc., generally can be rated current of 2 times the rated current of the transformer, the selection of CJl0, CJ20, etc..
7) for the electric heating equipment, such as electric resistance furnace, electric heater, the load of the cold state resistance is small, so the starting current corresponding to a large number of. When the contactor is used, it is not to be considered (starting current), and the load current of the rated current is selected. Model can choose CJl0, CJ20, etc..
8) due to the gas discharge lamp starting current, starting time, for the control of lighting equipment, can be rated current 1.1 to 1.4 times the selection of AC contactor, model CJl0, CJ20, etc..
9) contactor’s rated current is refers to the contactor in long-term work under the maximum allowable current, the duration is less than or equal to 8 hours and is installed on the open control panel, if the poor cooling conditions, the choice of contactor, rated current of a contactor according to the load current rating of 110% ~ 120% selected. For a long time working motor, because the film has no chance to get rid of, so that the contact resistance increases, resulting in more than the allowable temperature rise of contact. In the actual use, the rated current of the contactor can be reduced by 30%.
Identify the ac magnetic contactor and magnetic relay
A simple introduction
Electromagnetic relay is a relay that generates a predetermined response from the relative motion of the mechanical component in the input circuit current.
The electromagnetic contactor is one of the important components in the automatic control system. When the electromagnetic coil of the contactor is electrified, produces a strong magnetic field, makes the static iron core generates magnetic force to attract the armature, and drive action contact: normally closed contact is disconnected, normally open contact is closed, the two are linked. When the coil power, the electromagnetic force disappears, the armature of the release spring release, to make the contact recovery: normally closed contact is closed, normally open contact is disconnected. In industrial electrical, the model of the contactor is a lot of electric current in the range of 5A-1000A, its use is quite extensive. In electrical engineering, the contactor is a kind of used to connect or disconnect the AC and DC main circuit with load or large capacity control automatic switch circuit, the main control object is a motor, used also for other power loads, such as electric heaters, electric welding machine, lighting device contactor can not only connect and disconnect the circuit, but also has low voltage release protective effect.
2 classification of electromagnetic contactor
(1) AC contactor. Mainly in the electromagnetic mechanism, contact system, the arc device, etc.. Commonly used is CJ10, CJ12B, CJ12 and other series.
Because the AC electromagnetic contactor coil commonly used AC power supply, after the excitation contactor, usually a high decibel “slightly” noise, which has also become the characteristics of electromagnetic contactor. Although after the 1980s, all the development of AC contactor electromagnet soundless and power-saving, one of the basic feasible solution is the AC power supply with a step-down transformer, the internal rectifier DC conversion power supply, but the complex control mode does not see more.
(2) direct current contactor. Generally used in the control of DC electrical equipment, the coil in the DC power, DC contactor of the principle and structure of the structure is the same as the AC contactor. Because it can quickly cut off the main circuit of AC and DC and can frequently connected with the current control (some types of up to 800 Amperes) circuit device, so often used in motor do for the control of the object, but also can be used as factory equipment, electric heater, machine tools and all kinds of electric power unit control power load, and as a remote control device.
(3) air type contactor. Mainly by the contact system, the electromagnetic operating system, support, auxiliary contacts and shell (or chassis).
(4) vacuum contactor. Contactor vacuum contactor for the contact system by vacuum chamber degaussing.
(5) semiconductor contactor. The contactor of the current operation of the electric current operation by the use of the circuit breaker and the circuit breaker.
Three, electromagnetic relay and contactor
The difference between electromagnetic relay and contactor is to see their specific use.
Relay (1) the main role is signal detection, transmission, transforms or processing, through breaking the circuit current is usually small, that is generally used in the control circuit and the main circuit comparison).
(2) the main effect of the contactor is to connect or disconnect the main circuit. The so-called main circuit is a circuit operation or not, whether the circuit is connected to the symbol. The concept of main circuit and control circuit. General main circuit through the current ratio control circuit. Therefore, as the first floor of a friend said, large capacity contactors are generally with the arc extinguishing cover (for high current breaking meeting to produce arc, the arc shield arc, contact burn).
However, if a main circuit works less, then it can be used as a device for the main circuit of the relay. Relay as a contactor. But if a main circuit current is very large, so that the use of on-off of the main circuit of the contactor capacity is very large, to make such of the contactor of the current is also very large. That is to say current flowing through the control circuit of the utility model is very large, with the ordinary relay to on-off control circuit. At this time, you can choose to use as a contactor to the use of electrical appliances as the control circuit is broken, the role of the contactor in this situation is the relay.
air conditioner contactor
- At Saturday July 18th, 2015
- By Jacky Zheng
- In Technology
0
In electrical engineering, because it can quickly cut off the main circuit of AC and DC and can frequently connected with the current control (some types of up to 800 Amperes) circuit device, so often used in motor do as the control object, can also be used to control factory equipment, electric heater, machine tools and all kinds of electric power unit and power load contactor can not only connect and disconnect the circuit, but also has low voltage release protective effect. Contactor control capacity, suitable for frequent operation and remote control. Is one of the important components in the automatic control system. In industrial electrical, the model of the contactor is a lot of electric current in the range of 5A-1000A, its use is quite extensive.
AC contactor is used to open and close circuit, with auxiliary contacts to control loop. The main contact is normally open contact, and the auxiliary contact often two pairs of normally open contact and normally closed contact, small contactor is also often used as the intermediate relay with the main circuit. The contact of AC contactor, made of silver tungsten alloy, has good electrical conductivity and high temperature resistance. The action of AC contactor power source to communicate through the generated by the iron core coil with a magnetic field, the electromagnet core is made up of two “mountain” shape of young silicon steel sheet laminated, which a fixed iron core, a coil is sheathed, voltage can choose a variety of. In order to make the magnetic stability, pull side core plus short circuit ring. AC contactor is on the loss of power, relying on the spring reset. The other half is the active iron core, the structure and the fixed iron core, used to drive the main contact and auxiliary contact closure. More than 20 amps contactor with arc shield, the circuit is disconnected from the electromagnetic force, fast breaking arc, the protection of contact. With a high frequency of operation, the highest operating frequency can be up to 1200 times per hour when the power is turned on and off. The service life of the contactor is very high, the service life of the machine is usually ten million times.
Technology development
AC contactor is made as a whole, and its appearance and performance are improved, but the function is always the same. Regardless of the extent of the development of the technology, the ordinary AC contactor has its important status. Air electromagnetic contactor electromagnetic contactor (in English: magnetic Contactor) is mainly composed of a contact system, electromagnetic operating dynamic system, bracket and an auxiliary contact and the shell (or frame). Because the AC electromagnetic contactor coil commonly used AC power supply, after the excitation contactor, usually a high decibel “slightly” noise, which is the electromagnetic contactor characteristics. After the 1980s, countries of AC contactor electromagnet soundless and power-saving, one of the basic feasible solution is the AC power supply with a step-down transformer, the internal rectifier DC conversion power supply, but the complex control mode does not see more. The vacuum contactor is vacuum contactor contactor contact system by vacuum chamber degaussing. Semiconductor contactor is a kind of contactor, which is operated by the conduction state and the state of circuit breaker. Permanent magnet contactor permanent magnetic AC contactor is using pole same-sex repulsion, opposites attract the principle, permanent magnet drive mechanism to replace the traditional electromagnet drive mechanism and the formation of a micro power contactors.
What is a ac contactor?
– AC contactor is a kind of automatic control apparatus. Contactor is used in frequent switching on or off an AC circuit, also can cut off the fault current, has control of large capacity, long-distance operation, combined with relay can realize the operation timing, interlock control, a variety of quantitative control and pressure loss and undervoltage protection, widely used in automatic control circuit, the main control object is a motor, and can also be used for other electric power load control.
More than 20 amps contactor with arc shield, the electromagnetic force produced by disconnecting the circuit, fast breaking arc, to protect the contact.
– AC contactor mainly consists of four parts: (1) the electromagnetic system, including attraction coil, a movable iron core and the static iron core; (2) contact system, including three group of main contact and one to two groups of normally open and normally closed auxiliary contacts, it and the moving core is connected together mutually linked; (3) arc extinguishing device, generally larger capacity of AC contactor are equipped with arc extinguishing device to quickly cut off the arc, from the main contact of the burnt out; (4) insulation casing and accessories, all kinds of springs, transmission mechanism, a short circuit ring and a wiring column.
The meanings for AC Contactor’s parameters
The meaning of AC
AC 1 no sense or micro sense load and resistance furnace
Starting and breaking of AC 2 winding induction motor
Starting and running of AC 3 cage induction motor
AC – 4 cage induction motor starting, reverse or reverse operation, point move
5A AC discharge lamp
5B – AC incandescent lamp
On-off of 6a AC transformer
6B – AC capacitor group
7A – AC for household electrical appliances and similar to the low sense load
AC7b household electric motor load
Motor seal refrigeration compressor AC8a with manual reset overload release in
Sealed refrigeration compressor motor AC8b with automatic reset overload release in
(Ui) the meaning of
Contactor rated insulation voltage
(Ue)
Meaning rated working voltage
(Ith)
The meaning of the rated heat current
(Ie)
The meanings of the rated operating current and the rated operating power.
