Capacitor Contactor

The CJ36C Capacitor Contactor is a fundamental and essential device purpose-built for switching low-voltage shunt capacitors. It serves as a core component in a wide array of automatic reactive power compensation systems. This versatile product is engineered to operate in 50Hz AC electrical networks with a rated voltage up to 380V, handling capacitive loads as high as 50kvar to deliver consistent and effective power factor correction. As a product derived from the proven B-series AC contactor family, the CJ36C product represents our latest development, currently offered in five specifications to meet diverse application needs. Its mechanical layout introduces an improved design: the resistor switching assembly is located on either side of the main circuit, and it incorporates a crucial built-in discharge mechanism. When capacitors are disconnected, this mechanism automatically engages, reducing trapped residual voltage to below 50V within a swift 30-second period. This integrated feature of the product provides a significant advantage by removing the requirement for and cost associated with external discharge devices, streamlining system design. The main contacts continue to offer a well-conceived design for reliable, individual load switching. To ensure the Capacitor Contactor performs as intended throughout its service life, the following operating and installation criteria must be met: a) The ambient air temperature must remain within the bounds of ≥-5°C and +40°C, with a daily average value ≤+35°C. b) The installation site should not be above 2000m in altitude. c) The relative air humidity at the installation point should not exceed 50% when the temperature is +40°C. Also, for the wettest month, the average minimum temperature is ≤+25°C and the average maximum relative humidity is ≤90%. d) It is suited for environments with a pollution degree of 3. e) It falls under installation category III. f) It requires installation in an area without noticeable shaking, shock, or vibration. g) The contactor's mounting surface may be inclined up to a maximum of 5° from vertical.

The working principle, central to the product's effectiveness, is shown in Figure 1. The upper part of the diagram details the switching circuit, and the lower part the capacitor bank. The integrated resistor switching circuit, consisting of early-make contacts in series with resistors, is activated first upon coil energization. This provides a high-resistance path for the initial charge current, dramatically limiting inrush. Following this, the main contacts close to carry the normal operating current, simultaneously bypassing the resistors. Upon release, the main contacts open first, with the resistor circuit opening after a preset delay to suppress any induced overvoltage from the interrupting capacitive load. Additionally, a pair of normally-closed contacts automatically connect the discharge resistors across the capacitor terminals when the contactor is open, ensuring safe discharge. The CJ36C Capacitor Contactor utilizes a two-path resistor switching system. Because the associated capacitors are in a delta configuration, this design ensures that each phase is effectively protected during the switching transient, making this product a comprehensive, reliable, and cost-effective solution for all your capacitor switching requirements.

Auxiliary contact configuration: The CJ36C-63 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 are 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-63 type can be installed using M5 screws and anti-loosening washers, or using 35mm or 75mm mounting rails.