How to Choose the Right Frequency Inverter: A Comprehensive Guide & Brand Recommendations

I. Key Factors for Selecting a Frequency Inverter

1. Basic Motor Specifications

• Rated Power: The inverter’s rated power should be ≥ the motor’s rated power. For special loads (e.g., heavy-duty or impact loads), increase the inverter power by 10-50%.
• Rated Voltage/Frequency: Must match the motor and grid specifications (e.g., AC 220V/380V, 50Hz/60Hz) to prevent damage.
• Rated Current: The inverter’s rated current should exceed the motor’s rated current, with a 10-20% margin for frequent start-stop scenarios.

2. Load Type Analysis

• Constant Torque Loads (e.g., conveyors, mixers): Require inverters with stable torque output, ideally vector control models.
• Variable Torque Loads (e.g., fans, pumps): Load torque correlates with the square of speed. Choose V/F control models for optimal energy savings.
• Impact Loads (e.g., crushers): Need inverters with strong overload capacity (typically 150% overload for 30+ seconds); upsizing by one power class is recommended.

3. Control Method Options

• V/F Control: Cost-effective and simple, suitable for low-precision applications like fans or pumps.
• Vector Control: Open-loop (no speed feedback) or closed-loop (with encoder) options offer high precision (0.1% accuracy), ideal for machine tools or cranes.
• Direct Torque Control (DTC): Fast response makes it suitable for high-dynamic scenarios like lifting equipment.

4. Environmental & Functional Needs

• Environmental Conditions:
  • Temperature: Derate by 10% for every 10℃ above 40℃; use cooling systems if needed.
  • Humidity: Avoid environments with >90% humidity (no condensation).
  • Dust/Corrosion: Choose IP54+ enclosures or protective covers for harsh conditions.
• Essential Functions:
  • Braking units/resistors for high-inertia loads (e.g., centrifuges).
  • PID control for closed-loop systems (e.g., constant-pressure water supply).
  • Communication protocols (Modbus, PROFINET) for integration with PLCs or SCADA systems.

II. Recommended Brands (Including DREAM WE & Cost-Effective Options)

1. DREAM WE (Shenzhen DREAM WE Technology Co., Ltd.)

• Core Strengths: Covers 0.75kW–500kW, supporting V/F, open-loop vector (SVC), and closed-loop vector (VC) control. Delivers 150% starting torque at 0.5Hz, ideal for heavy loads.
• Key Features:
  • Built-in 16-segment PLC, PID, and RS-485 communication.
  • 1.5–15kW models include braking units; 18.5–90kW models have DC reactors for anti-interference.
  • Supports functions like power-failure ride-through and speed-tracking restart.
• Best For: General industrial equipment (conveyors, mixers), energy-saving retrofits for fans/pumps, and small lifting machinery—especially where cost-effectiveness and integration matter.

2. Fuji Electric

• Core Strengths: Comprehensive lineup with reliable FRENIC series, suitable for diverse industrial needs.
• Key Features: Advanced vector control (0.01% accuracy) and robust protection (overcurrent, overheating).
• Best For: Precision machinery, elevators, and scenarios requiring long-term stability.

3. DELIXI Electric

• Core Strengths: Local brand with fast delivery and extensive after-sales networks, offering strong value.
• Key Features: Basic vector control and built-in PID/multi-speed functions.
• Best For: Cost-sensitive applications like fans, pumps, or small production lines.

4. Senlan (Xiwang Senlan)

• Core Strengths: Established domestic brand with mature technology and easy access to spare parts.
• Key Features: Energy-saving modes and wide power range coverage.
• Best For: General industrial use and auxiliary metallurgical equipment.

5. Sine Electric

• Core Strengths: Cost-effective with quick service response, focusing on medium-low voltage applications.
• Key Features: Open/closed-loop vector control and optional braking units.
• Best For: OEM industries (packaging machinery, logistics conveyors).

III. Scenario-Specific Recommendations

1. Fans/Pumps (Variable Torque, Energy Savings)

• Top Picks: DREAM WE (optimized energy algorithms), DELIXI (cost-effective), Senlan (reliable).
• Tips: Prioritize energy-saving modes (sleep/wake, auto-tuning); 1.1x motor power is sufficient.

2. General Industrial Equipment (Constant Torque)

• Top Picks: DREAM WE (strong overload capacity), Fuji Electric (stable), Sine Electric (value).
• Tips: Ensure inverter current ≥ motor current; 150% overload for 1 minute is required for frequent starts.

3. High-Precision Equipment (Machine Tools, CNC)

• Top Picks: DREAM WE (closed-loop vector models), Fuji Electric (advanced vector series).
• Tips: Require ≤0.5% speed accuracy, ≤10ms response time, and PROFINET compatibility.

IV. Step-by-Step Selection Process

1. Gather Data: Record motor power, voltage, current, load type, and duty cycle.
2. Filter by Function: Shortlist brands with required features (braking, communication, etc.).
3. Compare Brands: Evaluate price, lead time, and local service for 2–3 options.
4. Test & Validate: Pilot small batches to verify stability and energy efficiency in real conditions.