A general three-phase contactor, a total of 8 points. Three road three road input. Output. There is a control point two. Input and output is the corresponding. Very easy to see. If you want to add a word. There is also a need from a terminal output point line received a control point.
Two, we should know the principle of AC contactor. He is with the external power supply to the coil. The electromagnetic field. Power. Power. Contact point is disconnected. To know the principle. You should clarify the external power supply contact. Also two contact is generally in the contactor coil. And lower. On the other side. Several other input and output are generally in the upper. Look to know. But also pay attention to and what is the power supply voltage (220V or 380V). Generally mark. And pay attention to the contact point is normally closed and normally open. If the self-locking control. Based on the principle of cut lines on it. The selection of AC contactor:
(1) intermittent operation equipment. Contactor is at 80%. The 100A AC contactor, can only control the maximum rated current is below 80A.
(2) equipment for continuous operation. According to the 67-75% contactor. 100A AC contactor, can only control the maximum rated current is below 67-75A.
(3) equipment repeated short-term work. According to the 116-120%. The AC contactor 100A, can only control the maximum rated current is below 116-120A
Reasons causing the failure are:
(1) oil, Hua Mao, foreign body contact.
(2) the long-term use, the oxidation of the contact surface.
(3) the arc ablation defects, burr or formation of scrap metal particles.
(4) the moving part blocked.
A processing method:
(1) for contact oil, flower hair or foreign body, can use cotton dipped in alcohol or gasoline to scrub.
(2) if the silver or silver alloy contact, the contact surface oxide layer or the formation of minor burns and black under the arc action, generally do not affect the work, available alcohol and gasoline or carbon tetrachloride solution scrubbing. Even if the contact surface is burned with uneven, can only use fine file clear around splash bead or burr, do not file repair too much, so as not to affect the contact life. For the copper contact, if the burn to a lesser extent, with fine file to smooth uneven repair can be, but does not allow the polished with fine emery cloth, lest the quartz sand in contact, and can not maintain good contact; if serious burn, the contact surface is low, must be replaced with new contacts.
(3) the moving part blocked, can be disassembled for maintenance.
Model the meaning of meaning items of AC contactor AC contactor, DC contactor models in the use of attention
1, the excitation coil voltage should be 85%~105%Un.
2, the core circuit ring should be intact.
3, core, contact support action parts and other moving parts should be flexible.
4, iron core, armature end face contact is good, no foreign body.
5, contact surface contact is good, have certain distance and high pressure.
6, the operating frequency should be within the allowable range.
