Reactive Power Compensation Control Cabinet Contactor

The CJ36C Reactive Power Compensation Control Cabinet Contactor stands as a specialized switching component engineered for the precise control of low-voltage shunt capacitors within compensation systems. As a dedicated solution, it is widely integrated into automatic compensation equipment designed for reactive power correction. This reliable product is designed for AC power systems with a frequency of 50Hz and a rated working voltage up to 380V, capably making and breaking connections to capacitor banks rated up to 50kvar to achieve targeted power factor improvement. Derived from the robust B-series AC contactor platform, this Reactive Power Compensation Control Cabinet Contactor is a recent innovation in our manufacturing portfolio, currently available in five distinct specifications to suit various cabinet designs. Its construction features a notable evolution: the resistor switching circuit is strategically positioned on both sides of the main power section and is enhanced with an integrated discharge device. This built-in feature automatically connects to the capacitors upon their disconnection from the circuit, ensuring that any residual voltage decays to a safe level below 50V within 30 seconds. By incorporating this functionality directly into the product, system designers can simplify control cabinet layouts and reduce costs by eliminating the need for separate external discharge units. The main contacts retain a rational, robust design for dependable, standalone load operation. To guarantee flawless performance within the confines of a compensation cabinet, this contactor must be applied under the following environmental and mounting guidelines: a) Ambient air temperature should range from ≥-5°C to +40°C, with a 24-hour average not exceeding +35°C. b) Installation altitude is limited to 2000m. c) Humidity conditions: relative humidity ≤50% at +40°C; the monthly average minimum temperature of the wettest month ≤+25°C, and that month's average maximum relative humidity ≤90%. d) It is intended for use in pollution degree 3 environments. e) The installation category is III. f) Mounting must be in a location within the cabinet that is free from significant shaking, impact, or vibration. g) The contactor should be installed with its mounting surface tilted no more than 5° from the vertical.

The sophisticated operation, illustrated in Figure 1, ensures smooth capacitor management. The schematic above the dotted line represents the control logic, while below lies the capacitor bank. Upon coil energization, the resistor switching circuit (early-make contacts with series resistors) closes first, allowing a controlled, limited current to charge the capacitors and suppress inrush. The main contacts then close, carrying the full load and shorting the resistors. During de-energization, the sequence reverses: main contacts open first, followed by a timed delay before the resistor circuit opens to clamp switching overvoltage. Furthermore, two normally-closed contacts work with the resistors to form an automatic discharge path, active only when the contactor is released, ensuring safe cabinet maintenance. The CJ36C Reactive Power Compensation Control Cabinet Contactor employs a two-path resistor switching design. Given that the capacitors are internally delta-connected, this ensures each phase is protected during engagement, making it an ideal, self-contained, and safe component for modern reactive power compensation control cabinets.

Auxiliary contact configuration: The CJ36C-50 model can be equipped with 6 auxiliary contacts.

Two types of auxiliary contacts are available:

CA7-10 (normally open) and CA7-O1 (normally closed). Users can specify their requirements when ordering.

Note: 1. Because parallel capacitors operate under an overcurrent of 1.3ln for extended periods, and capacitors in power systems always operate at full load, these conditions were considered in the capacitor design. Therefore, the contactor and connectors for switching the capacitor must be able to withstand a continuous overcurrent of at least 1.3In (not considering the capacitor's allowable positive deviation of +15%). Therefore, it is recommended to use this type of contactor according to the parameters in parentheses.

2. In - Rated current of the capacitor.

Outline and Installation Dimensions

The CJ36C-50 type can be installed using M5 screws and anti-loosening washers, or using 35mm or 75mm mounting rails.