A circuit breaker is a current protection actuator that operates in a switching mode, which can be used to connect and disconnect load circuits, as well as to control infrequently started motors. Its functions are equivalent to the sum of some or all functions of electrical appliances such as knife switches, overcurrent relays, voltage loss relays, thermal relays, and leakage protectors. Circuit breakers have various protection functions (overload, short circuit, undervoltage protection, etc.), adjustable action values, high breaking capacity, and convenient operation. Therefore, they are widely used and are an important protective appliance in medium and low voltage distribution networks
Testing requirements:
Due to long-term operation, the rear moving contact of the circuit breaker has slight oxidation, with black oxide and slight dust adhering to the surface. At the same time, there is residual residue of the original conductive grease on the pile head after drying.
. The above reasons can cause the contact resistance between the pile head and the frame plug-in to increase, causing local temperature rise of the circuit breaker, causing CT to be damaged by heat, causing the circuit breaker to burn out. At the same time, loose CT connection plugs can lead to misoperation of the tripping unit
In long-term operation, it is required that the temperature rise of electrical contact should not exceed the specified value when passing through the rated current for a long time. Contact resistance requires stability
When passing through short-circuit current for a short time, it is required that the electrical contact does not undergo fusion welding or splashing of contact material. During the closing process, it is required that the contact can close the short-circuit current without welding or serious damage
During the disconnection process, it is required that the electrical wear of the contact during circuit disconnection should be minimized as much as possible
Perform surface dust removal and cleaning operations on the upper and lower pile heads and dynamic and static contacts of the circuit breaker
Function of testing report:
1. Project bidding: Issue authoritative third-party CMA/CNAS qualification report
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1. Telephone communication and confirmation of requirements
2. Recommend solutions and confirm quotations 3. Mail samples and arrange testing 4. Progress tracking and result feedback 5. Provide reports and after-sales service 6. If urgent or priority processing is requiredTesting and testing characteristics:
1. The testing industry is fully covered, meeting different testing needs
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4. Free initial testing, with no testing fees charged
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6. Short cycle, low cost, and attentive service 7. Possess authoritative qualifications such as CMA, CNAS, CAL, etc 8. The testing report is authoritative and effective, and is generally used in China