Contacts for Support of Capacitors are specially designed for the operation of power factor correction capacitors (usage category AC-6b). The capacitors are pre-charged through resistors that reduce the inrush current to the contactor during activation of the special CEM_CN contactors. After pre-charging, the main contactors close, allowing the rated current to pass.
Advantages:
- Supports on DIN rails and mounting plates
- Technical specifications compliant with IEC 60947-4
- Built-in pre-charge resistors
- High reliability
- Reduced dimensions
- Standard control voltage: 230V AC
Operating principle: When a capacitor bank is connected, the capacitors are uncharged, and the system perceives them as a short circuit for a brief moment. The inrush current results from this short circuit and typically lasts a few milliseconds. It can reach up to 100 times the rated current, which is one of the main causes of reduced capacitor lifespan. The CEM CN contactor is equipped with soft-start resistors that limit the high inrush current during capacitor connection. It also features a contact block with a preset activation, which engages before the main contacts, thus limiting the inrush current. However, the soft-start resistors do not affect the final load, as they disconnect after 5 milliseconds. After this phase, only the capacitors remain connected in parallel with the inductive load, providing proper power factor correction.
Benefits: This process increases the lifespan of the capacitors and prevents network distortions.