| Model Part | Senso | Detailed Explanation |
| VFD | Delta Inverter Identifier | Abbreviation for Variable Frequency Drive, the universal prefix for Delta’s industrial automation inverters. |
| 55 | Applicable Motor Power | For 5.5kW (7.5HP) motori; this is the rated output power of the drive. |
| C | Series Code | C2000/C2000+ Series – Delta high-performance general-purpose vector inverter, supporting induction motors and permanent magnet synchronous motors. |
| 43 | Voltage Class & Phase | 4 = 3-phase 400V class (380~480V); 3 = 3-phase input (vs. 1 for single-phase). |
| UN | Control Mode & Features | Supports Vector Control (FOC), Torque Control (TRQ), high-performance algorithm, 200% starting torque at 0.5Hz. |
| -21 | Version & Configuration | Standard version: built-in braking unit (selected power ratings), no built-in EMC filter (external available), compliant with international standards. |
- Core Technical Specifications (Official 2026 Data)
| Categoria | Item | Valore | Note |
| Basic Specs | Rated Power | 5.5kW (7.5HP) | For 5.5kW 3-phase induction motors |
| Input Voltage | 3-phase 380~480V (+10%/-20%) | 47~63Hz, wide voltage range | |
| Rated Output Current | 12UN (heavy duty) / 10.8UN (light duty) | Continuous operation in heavy-duty mode | |
| Output Frequency Range | 0.1~600Hz | For both low‑ and high‑speed applications | |
| Control Performance | Control Mode | Sensorless Vector, Closed-loop Vector, V/F Control | Switchable closed/open loop |
| Starting Torque | 200% rated torque at 0.5Hz | Ideal for heavy starting loads | |
| Overload Capacity | 150% for 60s; 200% for 3s | For shock loads | |
| Speed Accuracy | ±0.5% (open-loop) / ±0.02% (closed-loop) | High precision speed control | |
| Torque Response Time | ≤10ms | Fast dynamic response | |
| Hardware | Protection Degree | IP20 (cabinet mount) | Finger‑safe; clean environment recommended |
| Cooling | Forced air (removable fan) | Easy maintenance, lunga durata | |
| Built-in Functions | Braking unit (≤7.5kW), PLC (5,000 steps) | High integration, fewer external parts | |
| Communication | RS-485 (Modbus RTU) standard | PROFINET/EtherNet/IP/CANopen optional | |
| Environment | Operating Temp | -10~40°C (derate 40~50°C) | Derate 1% per °C above 40°C |
| Storage Temp | -20~60°C | Avoid moisture & corrosive gas | |
| Humidity | 5~95% (non‑condensing) | Suitable for industrial environments |
III. Caratteristiche principali & Advantages
3.1 High‑Performance Control
Vector control: Precise independent torque & speed control for complex loads.
Built-in PLC: 5,000-step logic programming for simple automation, reducing external PLC dependency.
Auto energy saving: Dynamically adjusts output voltage; saves 20~50% at light load.
Motor auto-tuning: Completes matching in <10s, simplifies commissioning.
3.2 High Reliability Design
Modular structure: Hot-swappable keypad, expandable I/O and communication cards for easy maintenance.
Full protection: Overcurrent, sovratensione, sottotensione, overheat, sovraccarico, phase loss, earth fault, ecc.
Safe stop: Supports STO (Safe Torque Off), SIL 2 certified.
Wide grid tolerance: Withstands ±15% voltage fluctuation for harsh grids.
3.3 Flexible Communication & Expansion
Standard RS-485 Modbus RTU for multi-drive network control.
Optional modules: PROFINET, EtherNet/IP, PROFIBUS DP, CANopen.
Compatible with Siemens, Mitsubishi, Rockwell PLCs via standard telegrams and process objects.
Remote monitoring & diagnostics via Delta DIAStudio or TIA Portal.
- Applications & Selection Tips
4.1 Recommended Applications
| Industry | Applicazioni tipiche | Features |
| General Machinery | Pumps, tifosi, compressori, mixers | Energy saving, stable operation, longer equipment life |
| Material Handling | Conveyors, cranes, hoists, packaging machines | High precision speed control, heavy start, quick stop |
| Metal Processing | Lathes, milling, grinding, punching machines | High response, precise positioning, torque control |
| Textile & Dyeing | Textile machines, dyeing machines, stenter frames | Constant tension, synchronous operation, wide speed range |
| Plastic & Rubber | Injection molding, extrusion, blow molding | Significant energy saving (20~60%), stable pressure control |
4.2 Selection Key Points
- Power matching: Use VFD055C43A-21 for 5.5kW motors; avoid undersizing.
- Load type:
Constant torque (trasportatori, mixers): use heavy-duty mode (12UN).
Variable torque (tifosi, pumps): light-duty mode (10.8UN) for better efficiency.
- Control requirements:
High-precision positioning: use encoder (PG card) closed-loop vector.
Network control: add communication module (per esempio., PROFINET).
- Environment:
High temperature: extra cooling or derating required.
Dusty environment: dust cover + regular fan cleaning.
- Replacement Models & Upgrade Path
5.3 Upgrade Suggestions
- Basic upgrade: VFD‑M/GD10 → C2000+ for better precision & functions.
- Communication upgrade: Add PROFINET card for Industry 4.0 connectivity.
- System upgrade: Combine with Delta PLC (DVP series) & HMI for full automation solution.
Buying Notes
- Confirm suffix -21 (standard version), avoid old versions (per esempio., -00).
- Verify power & attuale: 5.5kW → 12A rated.
- Buy from authorized Delta channels for genuine product & service.
- Order accessories as needed: communication card, keypad, braking resistor.
VII. Installazione & Maintenance
7.1 Installation Rules
- Mounting: Wall/cabinet mount, installazione verticale; ≥150mm clearance top & bottom for ventilation.
- Cablaggio:
Separate power & control cables to avoid interference.
Shielded cable for signals, single‑end grounding.
Braking resistor matched to power (≤7.5kW internal; external ≈100Ω/500W).
- Grounding: Ground resistance ≤4Ω for safety & noise immunity.
Delta VFD055C43A-21 is a high‑performance 5.5kW vector inverter from the C2000+ series, featuring high precision, reliability, and expandability for diverse industrial applications. With built-in PLC, wide voltage tolerance, and complete protection, it is an excellent choice for general industrial drive solutions. Select based on motor power, tipo di carico, control requirements, and environment for optimal performance and cost-effectiveness.
Complete Replacement Guide for Delta VFD055C43A-21
- Delta Internal Replacements (C2000+ Series, Seamless Compatibility)
1.1 Direct Same‑Series Replacements
| Fault Code | Cause | Solution |
| OC | Overcurrent | Check motor short, sovraccarico, acceleration time |
| OV | Overvoltage | Check mains voltage, deceleration time, braking resistor |
| UV | Undervoltage | Check input phase, voltaggio, cable size |
| OH | Overheat | Check fan, ventilation, ambient temperature |
| PH | Phase loss | Check input/output wiring, motor winding |
1.2 Near‑Power Replacements
| Modello | Power | Corrente nominale | Key Features | Application |
| VFD055C43A-21 (Original) | 5.5kW | 12UN / 10.8UN | C2000+, vector, built-in brake, RS-485 | General industry |
| VFD055C43A-21 (Upgraded) | 5.5kW | 12UN | Better cooling, 10,000-step PLC, more protocols | New projects |
| VFD055CH43A-21 | 5.5kW | 12UN | CH2000, fan/pump specialized | Fans, pumps |
| VFD055CP43B-21 | 5.5kW | 12UN | CP2000, hoist/crane dedicated | Cranes, hoists |
- Global Brand Replacements (5.5kW / 400V Vector)
2.1 Premium Brands
| Marca | Modello | Series | Control | Advantage |
| Siemens | 6SL3210-1KE21-3UF1 (G120C PN) | SINAMICS G120C | Vector/V/F | PROFINET, EMC filter |
| Mitsubishi | FR-A840-00720-2-60 | FREQROL A840 | Vector | High response, built-in PLC |
| Yaskawa | CIMR-AB4A0018FBA | A1000 | Vector | Low noise, stable |
| Schneider | ATV320U75N4 | Altivar 320 | Vector/V/F | Compact, multi-protocol |
| ABB | ACS550-01-012A-4 | ACS550 | DTC | High torque accuracy |
2.2 Cost‑Effective Brands
| Marca | Modello | Series | Control | Advantage |
| Inovance | MD280NT5.5GB | MD280 | Vector | PROFINET supported |
| Veichi | AC70-T3-055G | AC70 | Vector | Full-featured, basso costo |
| INVT | CHF100A-5R5G/7R5P-4 | CHF100A | Vector | Built-in brake un |
III. Critical Replacement Rules (Must Follow)
- Power & attuale: Rated power ≥5.5kW, current ≥12A (heavy duty).
- Voltage: 400V class (380~480V) only; do NOT use 200V directly.
- Control: Prefer vector control for matching dynamics.
- Sovraccarico: At least 150% for 60s.
- Communication: RS-485 standard; PROFINET/EtherNet/IP optional.
Mechanical Compatibility
Dimensioni: ~90×180×150mm – use same or smaller size.
Cooling: Forced air – keep airflow direction.
Brake unit: Internal for ≤7.5kW; match external if needed.
Keypad: Use Delta standard keypad or compatible.
Best Replacement by Application
General machinery: VFD055C43A-21 upgraded or Siemens G120C PN.
Fans & pumps: VFD055CH43A-21 or Schneider ATV320U75N4.
Cranes/hoists: VFD055CP43B-21 or Mitsubishi FR-A840.
Budget projects: Inovance MD280NT5.5GB or Veichi AC70-T3-055G.
- Upgrade Paths
4.1 Delta Internal Upgrade
- C2000 → C2000+ (performance & function improvement).
- Add PROFINET module (VFD-CM-PN01) for industrial networking.
- Pair with Delta PLC + HMI for full automation system.
4.2 Cross‑Brand Upgrade
- Communication: RS-485 → PROFINET / EtherNet/IP.
- Control: Open-loop vector → closed-loop vector with encoder.
- Sicurezza: Choose models with STO (SIL 2).
The Delta VFD055C43A-21 has a wide range of replacements.
Same‑brand (C2000+ upgraded) offers seamless compatibility.
Cross‑brand (Siemens G120C PN, Mitsubishi FR-A840) provides higher performance.
Always follow core parameter matching to ensure stable, reliable replacement without performance loss or equipment damage.
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