According to the control object, the number of operations and the use of contactor contactor categories and the corresponding category.
According to the rated voltage of the service position line selection.
According to the rated current load capacity of the main contact of the contactor.
4 for attracting coil voltage and current type, should be considered to control the power supply requirements.
The auxiliary contacts of the capacity to choose, according to demand of interlock circuit and connected to a contact of the interrupting current size considered.
6 for contactor is connected or disconnected ability, selection should pay attention to using some of the load, such as a capacitor, a tungsten filament lamp and lighting device, connected to its current value, on-off time is longer, selection should left margin.
Seventhly, for contactor electrical life and mechanical life problem, by known per hour, the average number of operations and the machine service life, need the electrical life of the calculation, if can not meet the requirements should be derating use.
The selection should consider environmental temperature, humidity, the use of workplace vibration, dust, chemical corrosion and so on, selection of different types of contactor, according to the corresponding environment.
Anlyses for lighting device for contactor, but also considering the type of lighting device, starting current, the starting time length and long-term working current, current contactor selection should be no more than 90% of the electrical equipment (line) rated current. The lighting device and a tungsten lamp capacitor compensation, should consider its on current value.
The design should consider the consistency of the one or two device action.
Maintenance of AC contactor
Check the project in operation: 1) whether the load current through the contactor's rated value;
2) if the indicating signal contactor and circuit state;
3) run the sound is normal, not because of bad contact from acoustic;
4) electromagnetic coil without overheating, there is no abnormal short ring electromagnet.
5) arc shield is loose and damage;
6) there is no burning auxiliary contact;
7) transmission parts without damage;
8) around the operating environment has no adverse factors such as operation, excessive vibration, poor ventilation, excessive dust etc..
The maintenance work in electrical equipment, should be on the contactor for maintenance work.
1) external maintenance:
A. external dust cleaning;
B. check whether the loosening of the fastener, especially the conductor connecting part, prevent loosening and contact heating;
2) contact system maintenance:
A. check whether the location of moving and static contacts are closed at the same time, whether the phase should be adjusted, if there is a contact spring;
B. check the contact degree of wear and wear depth should be less than 1mm, contact burning, open solder off, should be the timely replacement; slight burning, generally does not affect the use. Use the sandpaper not allowed to clean contact, use the plastic file;
C. insulation measurement and white resistance, resistance of not less than 10M;
D. check the auxiliary contact action is flexible, the contact should be in line with the provisions of the trip, check whether the contact is loose off, and found the problem, should be promptly repaired or replaced.
3) iron core part maintenance:
A. cleaning dust, especially the moving parts and the core pull contact surface;
CJ20 AC contactor
B. inspection of the iron core, the tightening of the core will lead to increased operational noise;
C. core short circuit ring has broken off or broken to be repaired in time.
4) maintenance of electromagnetic coils:
A. measuring coil insulation resistance;
B. coil insulation has no discoloration, aging phenomenon, the coil surface temperature should not exceed 65 degrees C;
C. check coil wire connections, such as welding, burning should be repaired in a timely manner. 5) arc cover partial maintenance:
A. to check whether the arc is damaged;
There is no loose and position change of B. arc extinguishing cover;
C. clearance of metal particles and debris in the gap of the arc extinguishing cover.