CAPACITOR SWITCHING CONTACTORS
When choosing switching contactors for capacitors used to compensate the reactive power present in the network, you should bear several aspects in mind:
- On being energized the capacitor is connected in parallel to the inductive network and the oscillating circuit produced by connecting the capacitor to the network will result in the passage of a high frequency current (from 3 to 15 kHz), which may be 160 times greater than the In current for 1 or 2 ms
- The presence of harmonic currents and the tolerance with respect to mains voltage determine the continuous passage, within the circuit, of a current whose value is around 1.3 times greater than the rated current In of the capacitor
- Because of the tolerances allowed by the manufacturer, the exact power of a capacitor may be 1.10 times greater than the rated power
The contactor employed must therefore be capable of working with:
- An elevated, albeit transient, peak current during the closing phase
- A closing current that may be 1.43 times greater than the rated current of the capacitor
The contactors offered by DUCATI Energia are specifically engineered to work in these conditions.
Select the type of contactor based on the working voltage and effective power (in kVAr) of the capacitor bank to be controlled.