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Safety and Protection
Low-voltage circuit breakers offer automatic disconnection in case of overload or short circuits, preventing damage and fires.
All three components contribute to a safer electrical environment, protecting both property and individuals. -
Reliability and Stability
Integrated protection functions in circuit breakers, such as leakage and overvoltage protection, enhance the reliability of electrical systems.
Surge protectors improve the stability of critical equipment and systems by reducing the impact of voltage fluctuations. -
Efficiency and Energy Conservation
Prompt disconnection of overloaded circuits by circuit breakers helps in saving energy and reducing waste.
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Maintenance and Cost Reduction
The ease of maintenance of low-voltage circuit breakers reduces service costs and downtime.
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What is the difference between a contactor and a relay?
Contactors control high-power circuits (e.g., motors, heaters) with main contacts rated ≥10A and arc-quenching devices. Relays handle low-current signals (e.g., control circuits) with smaller contacts. For example, the CJX2 AC contactor manages 18.5kW motors, while the JQX-13F relay suits ≤10A loads.
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Can DC and AC contactors be interchanged?
No. DC contactors use solid iron cores (no eddy current loss) with DC coils, while AC contactors have laminated silicon steel cores with short-circuit rings and AC coils. Interchanging them causes core overheating or contact welding. For instance, the CZ18 DC contactor is incompatible with the CJ20 AC contactor in design.
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How to select a contactor based on load type?
Resistive loads (e.g., heaters): Choose 1.2× rated current. Example: For a 3kW heater (13.6A), use CJX2-1201 (12A).
Motor loads: Account for 5–7× starting current. Example: For a 7.5kW motor (15A), select CJX2-2510 (25A).
Frequent start/stop: Opt for DC contactors or AC contactors with energy-saving modules (e.g., CJX2-N, 10M+ mechanical cycles). -
Why does a contactor release immediately after engagement?
Common causes:
1.Low control voltage: Measure coil voltage (should be ≥85% of rated value, e.g., ≥20.4V for 24V coil). Adjust power supply or transformer.
2.Excessive contact spring pressure: Reduce spring force (e.g., adjust CJX2-1810 spring from 0.8N/mm to 0.6N/mm) or replace springs.
3.Mechanical jamming: Clean iron core surfaces with gasoline and check shaft flexibility. -
How to address severe contact erosion?
1.Mild erosion: Polish contacts with #0 sandpaper or alcohol-wipe copper oxide layers.
2.Severe erosion: Replace contact sets (e.g., CJX2-32T for CJX2-3210) if thickness wears to ≤1/3 original size.
3.Prevention: Install RC snubbers (0.1μF + 100Ω) across loads to suppress arcing.
