What is the AC contactor, country hair electrical switch factory, www.guofadq.com 15957745520
AC contactor has under-voltage protection function, has certain overload capacity, therefore, also has the function of overload protection. AC contactor running excessive noise may be due to a short circuit ring peeling or cracking caused by. AC contactor core of the short circuit ring fracture can make dynamic and static iron core can not be released. The above is the 3 on the AC contactor is described, looks are very reliable, but in fact only second sentences is correct, to fully understand the mistake, must first clearly understand what is AC contactor, although some people have also been busy purchasing, but may on its most basic knowledge is not sufficient, so it is it is necessary to" know".
AC contactor to use the main points to open closed circuit, with the auxiliary contacts to the execution control instruction, thereby completing the power switch and control circuit. Typically, the main contact generally only normally open contact, and the auxiliary contacts often have two pairs of normally open and normally closed contact function. Next, through its composition, classification, basic parameter, parameter selection, operation and maintenance to be detailed.
The choice of parameters of AC contactor
Its content includes: rated voltage rated current; coil; rated voltage; operating frequency; the working current of auxiliary contact. Here also introduce about the rated current of the attention point : continuous operation contactor, choose according to the 67-75%, for example 100A AC contactor, can control the maximum rated current is below 67-75A equipment; running press 80% count. Repeated short-term work by 116-120%..
Operation and maintenance of AC contactor
Operation should be paid attention to: through the load current is less than rated current, and a signal indicative of stress and circuit state line, running normal sound, not because of poor contact and emit acoustic, electromagnetic coil without overheating, the short circuit ring electromagnet or unusual, interrupter enclosures without loosening and damage, the auxiliary contacts without burning case. In the operation process, also should pay great attention to maintenance work, the attention of the general cleaning external dust and timely check the fastener is loose, especially conductor connection part.
Only by understanding these basic things, fully understand what is AC contactor, in order to choose and answer customer questions, understand. Of course, these are just the most basic things, there are many things need to continue to accumulate.
AC contactor.
Mainly consists of four parts: ( 1) the electromagnetic system ( 2) contact system ( 3) arc extinguishing device ( 4) insulation casing and accessories
The classification of AC contactor
Because of its many types, thereby classifying methods vary, in general, it can be divided into electromagnetic, permanent magnet and vacuum type three. But in fact, can be considered according to the main shock series, arc extinguishing medium and have no contact to classify.
( 1 ) according to the main contact pole number: can be divided into unipolar, bipolar, triode, tetrode and pentode contactor. Monopolar contactor is mainly used for single-phase load, such as a lighting load, welding machine; bipolar contactor used for winding type asynchronous motor rotor loop; pole contactor used in three-phase load, such as motor control, the most widely used; quadrupole contactor is mainly used for four phase three wire lighting circuit, can also be used to control double loop motor load; pentode AC contactor to form self coupled compensating starter or control double cage motor, in order to transform the winding.
( 2) according to the arc extinguishing media: can be divided into air contactor, vacuum contactor. Rely on air insulated contactor used for general load, and the use of vacuum contactor used in coal mine, petroleum, chemical industry enterprises and the voltage on the 660V and 1140V and some other special occasions.
(3 ) to have no contact points: can be divided into contact with contact and contactless contactor. Common contactor for a contactless contactor contact contactor, which belongs to the electronic technology application of the product, generally uses thyristor as the circuit on-off element.
The basic parameters of AC contactor
( 1): refers to the main contacts rated voltage rated voltage, rated voltage should be equal to the load.
( 2): rated current contact at rated working condition of the current value. 380V three-phase motor control circuit, rated current can be approximately equal to two times the control power. Common rated current 5A, 10A, 20A, 40A, 60A, 100A, 150A, 250A, 400A, 600A.
( 3) breaking capacity: can be divided into the maximum switch on the current and maximum breaking current. Maximum switching current refers to contact closure will not cause contact welding of the maximum current value; maximum breaking current refers to the breaking of contact can be reliable arc extinguishing the maximum current. General switching ability is the rated current of 5 ~ 10 times. Of course, this numerical value and open circuit voltage, the higher voltage, switching capacity of the smaller.
( 4): action value can be divided into the pull-in voltage and release voltage. The pull-in voltage is refers to the contactor pull-in, slowly increasing the attraction coil voltage contactor can attract, the minimum voltage. Release voltage refers to the contactor pull-in, slowly reduce the pull-in coil voltage, maximum voltage contactor released. General provisions, pull-in voltage is not lower than the coil 85% of rated voltage, release voltage not higher than the coil 70% of rated voltage
( 5) attract coil nominal voltage: contactor when in normal work, attract coil and the voltage value.
( 6) the operating frequency: contactor in the attraction moment, attract coil consumption than large rated current of 5 ~ 7 times the current, if the operating frequency is too high, will make the coil severe fever, directly affect the normal use of the contactor. Thus need to operate the power to be restricted.
( 7) life: including the electrical life and mechanical life. The contactor mechanical life already amounted to more than ten million times, electrical life is about 5% ~ 20% mechanical life.