Earlier we knew the external accessories of the circuit breaker. In this article, we will understand the wiring mode and working conditions of the circuit breaker.
The wiring methods of the circuit breaker include front panel, rear panel, plug-in type, and drawer type. If the user has no special requirements, they are supplied according to the front panel. The front panel wiring is a common wiring method.
The biggest feature of the wiring behind the board is that the circuit breaker can be replaced or repaired. It does not have to be rewired. It only needs to disconnect the front-end power supply. Due to the special structure, the product has been equipped with special mounting plates and mounting screws and wiring screws according to the design requirements. It should be noted that the reliability of the contact of the large-capacity circuit breaker will directly affect the normal use of the circuit breaker. We must pay attention and install in strict accordance with the requirements of the manufacturer.
On the installation board of the complete set of equipment, we first install a circuit breaker mounting base. There are 6 plugs on the mounting base, and there are 6 sockets on the connection plate of the circuit breaker. There are connecting plates on the surface of the mounting base or bolts behind the mounting base. The mounting base is pre-connected with power and load wires. When in use, insert the circuit breaker directly into the mounting base. If the circuit breaker is broken, just pull out the bad one and replace it with a good one. Its replacement time is shorter than before and after the board, and it is convenient. Because plugging and unplugging requires a certain amount of manpower, the current of the plug-in products in China is limited to a maximum of 400A. This saves repair and replacement time. When installing a plug-in circuit breaker, check whether the plug of the circuit breaker is tight and securely tighten the circuit breaker to reduce contact resistance and improve reliability.
The access drawer of the circuit breaker is rotated clockwise or counterclockwise by a rocker. Both the main circuit and the secondary circuit adopt a plug-in structure, and the isolator necessary for the fixed type is omitted. In addition to the economy of use, it also brings great convenience to operation and maintenance, and increases safety and reliability. In particular, the main circuit contact tool holder of the drawer base can be used with the NT type fuse breaker contact tool holder.
The working conditions of the circuit breaker need to consider the following points: ambient air temperature, altitude, atmospheric conditions, pollution level, and control loop.
The upper limit of the ambient air temperature is + 40 ° C; the lower limit of the ambient air temperature is -5 ° C; the average value of the ambient air temperature for 24 hours does not exceed + 35 ° C.
The altitude of the installation site does not exceed 2000m.
The relative humidity of the atmosphere does not exceed 50% when the ambient air temperature is + 40 ° C; it can have a higher relative humidity at a lower temperature; the monthly maximum relative humidity of the wettest month is 90% the average monthly minimum temperature is + 25 ° C, taking into account the condensation that occurs on the product surface due to temperature changes.
The pollution level is level 3.
1. It should be able to monitor the integrity of the control circuit protection device and its trip and closing circuits to ensure the normal operation of the circuit breaker;
2. It should be able to indicate the normal closing and opening position of the circuit breaker, and there should be obvious indication signals during automatic closing and automatic tripping;
3. After the closing and tripping is completed, the command pulse should be released, that is, the power supply for closing or tripping can be cut off;
4. When there is no mechanical anti-jump device, an electric anti-jump device should be installed;
5. The accident trip signal circuit of the circuit breaker should be wired according to the "non-corresponding principle";
6. For equipment that may appear abnormal working conditions or failures, a notice signal should be installed;
7. The power supply of the spring operating mechanism and manual operating mechanism can be DC(direct-current) or AC(alternating current). The power source of the electromagnetic operating mechanism requires DC.