A circuit breaker is a switching device that can close, carry and break current under normal loop conditions and can close, carry and break current under abnormal loop conditions within a specified time. Circuit breakers are divided into high-voltage circuit breakers and low-voltage circuit breakers according to their scope of use. The division of high and low voltage lines is relatively vague. Generally, 3kV or more is called high-voltage electrical equipment.
The following conditions must be met for the equipment to operate normally:
Ambient air temperature: upper air temperature +40 ° C; ○ ambient air temperature lower limit -5 ° C; ambient air temperature 24 h average does not exceed +35 ° C.
Altitude: The altitude of the installation site does not exceed 2000m.
Atmospheric conditions: 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 the lower temperature; the monthly average maximum relative humidity of the wettest month is 90%, while the month The monthly minimum temperature is +25 ° C, taking into account the condensation that occurs on the surface of the product due to temperature changes.
Pollution degree: Pollution level is 3.
Control loop:
1. It should be able to monitor the integrity of the control circuit protection device and its jump and closing circuit to ensure the normal operation of the circuit breaker;
2. It should be able to indicate the position status of the normal closing and opening of the circuit breaker, and have obvious indication signals during automatic closing and automatic tripping;
3. After the closing and tripping are 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 circuit breaker's accident trip signal circuit shall be wired according to the “non-corresponding principle”;
6. A warning signal shall be installed for equipment that may have abnormal working conditions or faults;
7. The power supply of the spring operating mechanism and the manual operating mechanism can be DC or AC, and the power supply of the electromagnetic operating mechanism requires DC.