What Is Low-Voltage AC Contactor？
ZHIMING brand of the CJ20 series AC contactor for switching shunt capacitors (hereinafter referred to as “the contactor”) is mainly used in AC power systems with a frequency of 50Hz or 60Hz and a rated voltage up to 660V. It is designed for switching shunt capacitors in low-voltage reactive power compensation banks.
When equipped with a surge suppression device, the contactor can effectively limit inrush current during closing and suppress overvoltage during opening, thereby enhancing the safety and longevity of the power compensation system.
Structural Features of the Low-Voltage AC Contactor
- Arc chute design ensures safe arc extinction and longer contact life.
- Silver alloy contacts for better conductivity and resistance to welding.
- Surge suppression unit (optional): integrated resistor-inductor group effectively mitigates inrush current and overvoltage.
- Flexible installation: available with both panel-mounting and rail-mounting versions.
Product Parameters
| Item | Specification |
|---|---|
| Rated insulation voltage | Up to 660V |
| Rated working voltage | 380V / 660V |
| Applicable frequency | 50Hz / 60Hz |
| Utilization category | AC-6b (capacitor switching) |
| Rated operating current (AC-6b) | 20A ~ 630A (depending on model) |
| Rated control voltage (Coil) | AC 220V / 380V / 110V / DC 24V (customizable) |
| Conventional thermal current (Ith) | 25A ~ 800A |
| Mechanical life | ≥ 1 million operations |
| Electrical life (AC-6b) | ≥ 0.1 million operations |
| Installation category | Class III |
| Pollution degree | Class III |
| Protection class | IP20 (basic) can be enhanced with enclosure |
| Mounting method | Vertical, inclination angle ≤ ±5° |
| Ambient temperature | –5°C to +40°C; daily average ≤ +35°C |
| Relative humidity | ≤ 50% at +40°C (up to 90% at 25°C with condensation) |
| Altitude | ≤ 2000 meters |
| Standard compliance | GB/T 14048.1, GB/T 14048.4, IEC 60947-4-1 |
Main Technical Data of the Low-Voltage AC Contactor
Note: Other special specification models are supplied according to user requirements
| Type | Ui(V) | Ue(V) | Ith(A) | Rated operational current under intermittent periodic duty（A） | AC-3 Pe(kW) | Rated operational current under uninterrupted duty(A) | Weight(kg) | |||
|---|---|---|---|---|---|---|---|---|---|---|
| AC-1 | AC-2 | AC-3 | AC-4 | |||||||
| CJ20-10 | 690 | 220 | 10 | 10 | 10 | 10 | 2.2 | 10 | 0.353 | |
| 380 | 4 | |||||||||
| 660 | 5.2 | 5.2 | ||||||||
| CJ20-16 | 690 | 220 | 16 | 16 | 16 | 16 | 4.5 | 16 | 0.416 | |
| 380 | 7.5 | |||||||||
| 660 | 13 | 13 | 11 | |||||||
| CJ20-25 | 690 | 220 | 32 | 32 | 25 | 25 | 5.5 | 32 | 0.67 | |
| 380 | 11 | |||||||||
| 660 | 14.5 | 14.5 | 13 | |||||||
| CJ20-40 | 690 | 220 | 55 | 55 | 40 | 40 | 11 | 55 | 1.32 | |
| 380 | 22 | |||||||||
| 660 | 25 | 25 | ||||||||
| CJ20-63 | 690 | 220 | 80 | 80 | 63 | 63 | 63 | 18 | 80 | 2.9 |
| 380 | 30 | |||||||||
| 660 | 40 | 40 | 40 | 35 | ||||||
| CJ20-100 | 690 | 220 | 125 | 125 | 100 | 100 | 100 | 28 | 125 | 3 |
| 380 | 50 | |||||||||
| 660 | 63 | 63 | 63 | |||||||
| CJ20-160 | 690 | 220 | 200 | 200 | 160 | 160 | 160 | 48 | 200 | 5.5 |
| 380 | 85 | |||||||||
| 660 | 100 | 100 | 80 | |||||||
| CJ20-160/11 | 1140 | 1140 | 80 | 80 | 80 | |||||
Why Choose ZHIMING's Low-Voltage AC Contactor?
Optimized for Capacitor Switching
Our CJ20 series AC contactor is engineered specifically for switching shunt capacitors in low-voltage reactive power compensation banks. Tailored to 50Hz/60Hz AC systems with rated voltage up to 660V, it delivers reliable performance for core compensation applications.
Surge & Overvoltage Protection
When paired with a surge suppression device, this AC contactor effectively limits inrush current during closing and suppresses overvoltage during opening. It significantly boosts the safety and service life of the entire reactive power compensation system.
Broad Voltage-Frequency Compatibility
The AC contactor supports a wide operating range: 50Hz/60Hz frequency and rated voltage up to 660V. It seamlessly adapts to diverse low-voltage power grid requirements, eliminating compatibility issues for different application scenarios.
Versatile Application Scope
Ideal for low-voltage power capacitor banks, APFC systems, reactive power compensation cabinets, and industrial distribution panels for capacitor group switching. This AC contactor meets the switching needs of multiple reactive power compensation scenarios.
Flexible Customization Options
The AC contactor offers flexible configurations: default AC 380V coil voltage (per Chinese market standards), and customizable auxiliary contacts (e.g., 1NO+1NC) to match specific user requirements.
FAQ
What is the main purpose of the CJ20 series AC contactor?
The CJ20 series AC contactor is specifically designed for switching shunt capacitors in low-voltage reactive power compensation systems. It operates in AC power systems with frequencies of 50Hz or 60Hz and handles rated voltages up to 660V. Unlike general-purpose contactors, this AC contactor addresses the unique challenges of capacitor switching, including inrush current during energization and overvoltage during de-energization.
How does the surge suppression feature benefit this AC contactor?
When equipped with surge suppression devices, the AC contactor provides two critical protective functions. First, it limits inrush current during closing operations—capacitors can draw extremely high currents at the moment of energization, sometimes reaching 20 to 100 times normal current. Second, it suppresses overvoltage transients during opening operations. These protective capabilities extend the service life of both the contactor itself and the connected capacitors.
What are the typical applications for this AC contactor?
This AC contactor finds primary use in several reactive power compensation scenarios. Low-voltage power capacitor banks rely on these contactors for reliable switching operations. Automatic power factor correction systems use them to switch capacitor stages based on real-time power factor readings. Reactive power compensation cabinets in commercial and industrial facilities incorporate these contactors for load management.
What is the default coil voltage for this AC contactor if not specified?
The default control coil voltage for this AC contactor is AC 380V when no specific voltage is indicated in the order. This default follows Chinese market standards where 380V represents the common industrial control voltage. However, the AC contactor can be supplied with other coil voltages based on regional requirements or specific application needs.
Can auxiliary contacts be added to this AC contactor?
Yes, auxiliary contacts can be added to the AC contactor based on application requirements. These additional contacts provide status feedback signals, interlock functions, or control circuit connections beyond the main power switching contacts. Common configurations include 1NO+1NC (one normally open plus one normally closed) arrangements, though other combinations are available. Auxiliary contact requirements should be indicated separately in the bill of materials when ordering.
