Contactors For Power Capacitors

The CJ36C Contactors for Power Capacitors represent a specialized line of switching devices designed for the controlled connection and disconnection of low-voltage shunt power capacitors. They are extensively used in automatic compensation equipment for reactive power correction. These robust product are engineered for AC systems with a frequency of 50Hz and a rated working voltage up to 380V, handling capacitive loads up to 50kvar to reliably enhance power factor. Derived from the established B-series AC contactor platform, the CJ36C Contactors for Power Capacitors are a recent addition to our product line, currently offered in five distinct specifications. Their structural configuration presents a key difference: the resistor switching circuit assembly is located on both flanks of the main circuit block, and it incorporates a built-in discharge device. This innovative feature automatically engages when capacitors are switched out of the circuit, reducing the residual capacitor voltage to below 50V within 30 seconds. By incorporating this discharge capability, these product allow end-users to forgo additional external discharge components, leading to simplified installation and lower overall project costs. The main contacts continue to feature a rational, reliable design for independent load handling. To ensure specified performance, these Contactors for Power Capacitors require adherence to the following normal working and installation parameters: a) Ambient air temperature range: upper limit +40°C, 24-hour average ≤+35°C, lower limit ≥-5°C. b) Maximum installation altitude: 2000m. c) Humidity: at +40°C, relative air humidity ≤50%; the average minimum temperature of the wettest month ≤+25°C, and that month's average maximum relative humidity ≤90%. d) Rated for pollution degree 3 environments. e) Classified under installation category III. f) Must be mounted in a location free from significant shaking, shock, or vibration. g) The inclination of the mounting surface relative to vertical must not exceed 5°.

The operational sequence, depicted in Figure 1, ensures safe switching. The diagram above the dotted line shows the control circuit; below is the capacitor bank. The integrated resistor switching circuit (early-make contacts with series resistors) activates first upon coil energization, limiting inrush current during capacitor charging. Subsequently, the main contacts close to assume the load, shorting out the resistors. During de-energization, the main contacts open first, with the resistor circuit opening after a delay to mitigate overvoltage. Additionally, two normally-closed auxiliary contacts and resistors create an automatic discharge path: connected during contactor release to safely dissipate stored energy, and disconnected during engagement. The CJ36C product utilize a two-path resistor switching design. Because the controlled capacitors are internally wired in a delta configuration, activating this circuit ensures that a current-limiting resistor is inserted into each phase, providing comprehensive and balanced protection during every switching operation for enhanced system longevity.

 Auxiliary contact configuration: The contactor can be configured with auxiliary contacts at the top. The CJ36C-30 model can be configured with 4 auxiliary contacts.

Appearance and Installation Dimensions:

The contactor is easy to install. The CJ36C-30 model can be installed with M4 screws and lock washers, or with a 35mm mounting rail.