Schneider ATV21HD18N4 Variable Speed Drive 18.5kW 400V | Replacement, Equivalent & Selection Guide
The Schneider Electric ATV21HD18N4 is a 18.5kW (25HP) three-phase 400V AC variable speed drive from the Altivar 21 series, engineered for HVAC and pump applications. This page provides full technical specifications, compatible replacement models, application guidance, and a structured selection guide to help engineers and procurement teams make the right choice.
Technical Specifications
- Part Number: ATV21HD18N4
- Brand: Schneider Electric (Telemecanique)
- Series: Altivar 21 (ATV21)
- Motor Power: 18.5 kW / 25 HP
- Supply Voltage: 380–480V AC, 3-Phase
- Output Frequency: 0.5–400 Hz
- Input Current: ~38A (nominal)
- Output Current: 38A (nominal)
- Protection Rating: IP20 (panel mount)
- Control Mode: V/F, Sensorless Flux Vector
- Communication: Modbus RTU (optional CANopen, BACnet)
- Weight: ~11.65 kg
- Standards: CE, UL, cUL
Compatible Replacement & Equivalent Models
The following models are functionally equivalent or drop-in replacements for the ATV21HD18N4 in most HVAC and pump applications:
- Schneider ATV320U75N4B – Next-gen ATV320 series, 18.5kW 400V, enhanced EMC
- Schneider ATV630D18N4 – ATV630 series, 18.5kW, advanced process control
- ABB ACS580-01-038A-4 – 18.5kW 400V, direct equivalent for HVAC duty
- Siemens SINAMICS G120 PM240-2 18.5kW – Modular equivalent, 400V 3-phase
- Danfoss FC102 18.5kW 400V – HVAC-optimized equivalent
- Yaskawa GA700 CIMR-GA4A0038 – 18.5kW 400V general-purpose equivalent
Note: Always verify motor nameplate data, control wiring, and communication protocol before substituting. Contact Konmask for application-specific validation.
Why Choose the Original Model
- Proven HVAC Performance: ATV21 series is purpose-built for fans, pumps, and compressors with built-in PID control and sleep/wake functions.
- Energy Savings: Automatic energy optimization reduces motor losses at partial load — ideal for variable-torque applications.
- Compact Footprint: Optimized panel-mount design reduces cabinet space vs. general-purpose drives of the same rating.
- Native BMS Integration: Supports Modbus RTU, BACnet MS/TP, and LON for seamless building management system connectivity.
- Long Field Track Record: Widely deployed in commercial HVAC systems globally since 2005.
Typical Applications
- HVAC air handling units (AHU) and fan coil units
- Chilled water and condenser water pumps
- Cooling tower fans
- Exhaust and supply air fans in commercial buildings
- Irrigation and water supply pumps
- Industrial process pumps (constant and variable torque)
System Compatibility
- Motor Types: Standard asynchronous induction motors (IE2/IE3 compatible)
- Control Wiring: 24VDC logic inputs, analog 0–10V / 4–20mA reference
- Communication Buses: Modbus RTU (standard), optional BACnet MS/TP, CANopen, LON
- Braking: Dynamic braking resistor connection available (external resistor required)
- EMC Filter: Built-in Class C2 EMC filter
- Upstream Protection: Compatible with standard IEC type gG fuses or circuit breakers per Schneider coordination tables
Selection Guide
Use the following criteria to confirm the ATV21HD18N4 is the correct drive for your application:
- Motor Power: 18.5kW / 25HP — confirm motor nameplate kW rating
- Supply Voltage: 380–480V 3-phase — verify site supply voltage and tolerance
- Load Type: Variable torque (fans/pumps) — if constant torque or high starting torque is required, consider ATV320 or ATV630 series
- Enclosure: IP20 panel mount — if standalone IP54/IP55 enclosure is needed, specify ATV21 with external enclosure or select ATV320 book/compact variant
- Communication: Confirm BMS protocol (Modbus, BACnet, LON) and order appropriate option card if not standard
- Altitude & Ambient: Derate above 1000m or 40°C — contact Konmask for derating curves
Quality Assurance & Sourcing
- All units sourced from authorized distributors or verified surplus channels
- Each unit inspected for physical integrity, label authenticity, and firmware version prior to dispatch
- Traceability documentation available on request (batch records, COC)
- New, refurbished, and tested-used conditions available — clearly stated at time of quotation
- 12-month warranty on new units; 90-day warranty on tested-used units
How to Order
- Step 1: Confirm part number: ATV21HD18N4
- Step 2: Specify required condition: New / Refurbished / Tested-Used
- Step 3: Provide delivery destination for freight quotation
- Step 4: Submit RFQ via support@konmask.com or add to cart and proceed to checkout
- Lead Time: In-stock units ship within 1–3 business days; sourced units 5–15 business days
Replacement & Compatibility FAQ
Q: Can I replace ATV21HD18N4 with ATV320U75N4B directly?
A: In most HVAC fan/pump applications, yes. The ATV320 series is the official successor. Verify terminal mapping and parameter migration using Schneider’s migration guide.
Q: Is the ATV21HD18N4 still in production?
A: The ATV21 series has reached end-of-life (EOL). Schneider recommends migrating to ATV320 or ATV630. Konmask stocks remaining new and tested-used units.
Q: What is the difference between ATV21HD18N4 and ATV21HD18N4X?
A: The “X” suffix typically denotes an extended temperature or conformal coating variant. Confirm with Schneider documentation or contact Konmask for clarification.
Q: Can this drive control a 22kW motor?
A: No. For 22kW, select ATV21HD22N4. Oversizing the motor beyond the drive’s rated output current will trigger overcurrent faults.
Q: Do you provide Modbus configuration support?
A: Yes. Konmask provides basic commissioning documentation and can refer customers to certified Schneider integrators for full BMS integration.
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