Input Reactor

Scope of Application

1. Power supply causes significant interference to other equipment (interference, overvoltage)

2. Inter-phase voltage imbalance > 1.8% of the rated voltage

3. Extremely low-impedance lines (power Transformer is more than 10 times the rated value of the frequency converter)

4. Multiple frequency converters installed on a single line to reduce current limiting

5. Use of cosφ (power factor) correction capacitors or power factor correction units

Detailed Technical Breakdown

1. Core Functions

Harmonic Suppression

- Bidirectional isolation: Blocks grid harmonics from entering the frequency converter while preventing harmonics (e.g., 5th, 7th, 11th) generated by the converter from polluting the grid.

- Especially effective for high-frequency harmonics from IGBT rectification.

Voltage/Current Stabilization

- Overvoltage protection: Suppresses transient overvoltages (e.g., lightning strikes, switching surges).

- Phase balancing: Automatically adjusts phase current imbalance (threshold: 1.8%), reducing energy loss by 3–5%.

- Current limiting: Mitigates low-impedance surges caused by large-capacity transformers (10x the rated value of the frequency converter).

2. Typical Applications

- Industrial scenarios: Rolling mills, cranes, and other high-current equipment (≥400V/50Hz systems).

Sensitive grid environments:

- Lines with power factor correction capacitors (prevents resonance).

- Multi-converter parallel systems (prevents mutual interference).

- Facilities with strict THD requirements (<5%), such as medical/laboratory settings.

3. Technical Advantages

- Adaptive regulation: Responds to grid fluctuations in real-time (10ms-level).

- High compatibility: Supports multi-pulse rectification topologies (12-pulse, 18-pulse, etc.).

• Energy efficiency improvement: Reduces motor losses by 15–20% through three-phase current balancing.

4. Selection Guidelines

Key considerations:

1. System short-circuit capacity (mandatory installation if >20kA).

2. Existing THD level (recommended if >8%).

3. Load characteristics (priority for frequently start-stop devices).

This device essentially integrates active filtering and reactive power compensation into an intelligent power regulator, making it valuable in emerging fields such as renewable energy grid integration and smart factories. In practice, periodic thermal imaging checks on inductor components are recommended.