DDM 9/9 E6G3501 Double-Inlet Centrifugal Fan – ERM Motor, 3435 m³/h, 230V

Nicotra DDM 9/9 E6G3501 Double-Inlet Centrifugal Fan – ERM Motor, Maximum Efficiency

The double-width double-inlet (DWDI) centrifugal fan DDM 9/9 E6G3501 by Nicotra Gebhardt is the high-efficiency solution for air handling units (AHU), industrial and kitchen hoods, HVAC systems and commercial applications requiring medium airflow at low static pressures. All components – casing, motor and impeller – are manufactured by Nicotra Gebhardt, guaranteeing perfect compatibility, certified performance and an extended service life.

External rotor motor (ERM) – efficiency and optimal cooling

The external rotor motor (ERM) rated at 0.55 kW / 230 V / 50 Hz / 4-pole integrates the fan impeller directly onto the motor casing, eliminating belt or coupling drives. This compact design offers several advantages over internal rotor motors: larger cooling surface area, superior mechanical efficiency, lower noise levels and extended bearing life. The impeller mounted directly on the motor shaft enables efficient motor cooling via the airstream, preventing overheating. The motor features integrated automatic thermal protection.

Galvanised steel impeller with forward-curved blades

The impeller is manufactured from galvanised steel sheet with forward-curved blades, profiled to maximise airflow at low static pressures with minimum energy consumption. Dynamically balanced to ISO 1940, it ensures smooth, vibration-free and low-noise operation even at high speeds. The Ø298 mm inlet diameter allows direct integration into standard ductwork systems.

Direct drive – zero maintenance, maximum efficiency

The absence of belts, pulleys and intermediate transmission elements means:

• Zero periodic maintenance – no belt replacements or realignment
• No transmission losses – all motor torque is delivered directly to the impeller
• High reliability – fewer moving parts, fewer failure points
• Minimum operating costs – long-term savings compared to belt-driven alternatives

Delivery options for any installation

The DDM 9/9 E6G3501 is available in three configurations:

Recommended applications

The DDM 9/9 E6G3501 is suitable for: air handling units (AHU) and HVAC systems, industrial and kitchen hoods, hotels, restaurants and commercial spaces, offices and residential buildings with medium airflow requirements, fresh air supply systems with heating coils, installations with G4 filters for improved air quality.

Key advantages:

• DWDI design – 3435 m³/h airflow in a compact footprint
• ERM motor – superior efficiency and cooling vs conventional motors
• Galvanised steel forward-curved impeller, ISO 1940 balanced
• Direct drive – zero maintenance, zero losses
• Automatic thermal protection
• 3 configurations: standard / insulated BOX / plug & play
• Single-source Nicotra Gebhardt manufacture – guaranteed compatibility
• AMCA certified – verified performance

TECHNICAL SPECIFICATIONS TABLE:

FAQ – FREQUENTLY ASKED QUESTIONS:

Q: What is an ERM (External Rotor Motor) and why is it more efficient? A: An ERM (external rotor motor) has the rotor mounted on the outside of the stator, directly on the fan casing. In the DDM 9/9 E6G3501, the fan impeller is effectively the motor casing, providing a much larger cooling surface than a conventional motor. The results are superior energy efficiency, lower operating temperature, reduced noise and longer bearing life, all in a compact footprint. Compared to internal-rotor belt-driven alternatives, the ERM completely eliminates mechanical transmission losses and the need for belt maintenance.

Q: What is the difference between the standard, BOX and plug & play versions? A: The standard version supplies the fan as a standalone unit for integration into air handling units or custom equipment. The BOX version includes the fan mounted in a sound-insulated enclosure made from galvanised or RAL 9010 powder-coated steel, with 6 or 10 mm insulation and flanges for direct duct connection – significantly reducing noise transmitted to the surroundings and simplifying installation. The plug & play version adds a complete pre-wired inverter kit, so the fan is ready to connect and operate immediately upon delivery, without additional purchases or wiring.

Q: What does ISO 1940 dynamic balancing mean and why does it matter? A: ISO 1940 defines precision classes for dynamic balancing of rotating components. An impeller balanced to ISO 1940 produces minimal vibration during operation, resulting in low noise levels, reduced bearing wear, extended service life of the entire assembly and protection of the building structure from vibration transmission. It is an important quality indicator for fans intended for integration in air handling units or vibration-sensitive installations.

Q: What accessories are recommended with the DDM 9/9 E6G3501? A: For complete installations: BOX PLUS 9/9 plenum enclosure for duct mounting and noise reduction; ITR-9-50-DT or ITRS 9-60 DT electronic speed controller for airflow control; gravity return air damper on the discharge to prevent reverse airflow; BAC heating coil for fresh air preheating in winter; G4 filter box F300 to improve the quality of supplied air.

Q: Can it be integrated into BMS or automation systems? A: Yes. Via an inverter with 0–10 V or 4–20 mA analogue input, the DDM 9/9 E6G3501 can be automatically controlled by Building Management Systems (BMS) based on CO₂, air quality, temperature or differential pressure sensors, enabling energy-efficient variable air volume (VAV) ventilation.

Q: How can I order or request technical advice? A: You can order through the product page form, or contact us at +40 722 667 239 (phone/WhatsApp) for free technical advice on the optimal configuration, required accessories and integration into your installation.