DD 10/10 M9F1 three-phase 4-pole centrifugal fan in acoustic BOX enclosure — 7,000 m³/h

BOX DD 10/10 M9F1 is the Nicotra Gebhardt DD 10/10 M9F1 3F 4P 1V double-width double-inlet centrifugal fan delivered as a complete assembly — the fan pre-mounted and aligned inside an acoustic BOX enclosure. This is the size 10/10 model in the DD series — larger than the DD 9/9 (single-phase, ~4,000 m³/h) and below the DD 12/12 (three-phase, higher airflow) — the correct choice for medium-to-large industrial and commercial applications requiring 5,000–7,000 m³/h with a three-phase motor.

Motor configuration — M9F1 3F 4P 1V - conventional shaft motor, enclosed housing, aluminium, three-phase, 4 poles → ~1,420 rpm at 50Hz

Motor protection: IP55 — complete protection against dust and water jets from any direction, superior to the IP54 of smaller models. Class F insulation (resistant to 155°C winding temperature). Integrated thermal protection with automatic reset.

+SCT suffix — inverter-compatible

+SCT (Speed Controllable via Transformer/Inverter) means the motor is designed to operate at reduced voltages and variable frequencies — compatible with a variable frequency drive (VFD). This enables: airflow reduction based on actual installation demand; significant energy savings through the cubic power law (at 80% speed → ~51% of nominal consumption); programmable soft start eliminating mechanical start-up shock; automatic control via pressure, CO₂ or temperature sensors connected to the VFD's 0–10V input.

Why in an acoustic BOX enclosure — advantages over bare mounting

A bare-mounted DWDI fan (without housing) transmits directly into the installation space the mechanical noise of the motor and rotor, plus the aerodynamic noise of the airflow. In applications where the fan is located near occupied spaces — office suspended ceiling, adjacent plant room, service corridor — unattenuated noise can exceed 70–75 dB(A) at one metre distance.

The acoustic BOX enclosure addresses this through:

Acoustic and thermal insulation: housing panels are galvanised steel with a sound-absorbing core (mineral wool or rigid polyurethane) — reducing noise transmission through enclosure walls by 10–20 dB versus bare mounting.

Rigid anti-vibration structure: the metal frame does not transmit rotor vibrations to the building structure — eliminating structural resonance hum, a frequent problem with fans mounted directly on steel beams or metal ceilings.

Mechanical protection: the housing protects the fan and motor from coarse dust, accidental objects and unauthorised interference — relevant in industrial or technical spaces with multiple access.

Quick component access: the removable side panel allows access to the motor, terminal box and impeller for inspection and cleaning without complete assembly disassembly.

Mounting flexibility: air connections (inlet and outlet) can be configured in different orientations relative to the housing, allowing adaptation to installation geometry without structural modifications.

Typical applications for DD 10/10 in acoustic BOX

Medium-sized air handling units (AHU) where the fan-in-BOX constitutes the air transport module, with noise insulation provided by the enclosure itself. Office building plenums where the BOX is installed in suspended ceilings above occupied spaces. Industrial ventilation with noise constraints — precision workshops, laboratories, spaces where occupational noise standards require levels below 70 dB(A). Professional kitchen exhaust — serving large restaurant or catering kitchen installations requiring 5,000–7,000 m³/h with reduced noise. Collective residential buildings — technical ceiling with centralised extraction from 20–40 bathrooms or kitchens connected to a single main duct.

Comparison with adjacent DD series models:

The DD 10/10 is the correct choice when the DD 9/9 (single-phase) no longer covers the required airflow and when the installation has three-phase supply available. It bridges the gap from residential and small commercial applications to medium industrial and commercial applications.

FAQ

What VFD is compatible with the DD 10/10 M9F1? Any three-phase VFD with rated current ≥ 5.6A × 1.2 = 6.7A (20% safety factor). At 400V three-phase, this means a minimum 3 kW VFD. Choose a VFD with integrated or external EMC filter for installation in panels with sensitive equipment. Contact us for a specific recommendation.

Motor connection — D or Y? On the standard Romanian 400V three-phase network, connect the motor in star (Y). On 230V three-phase networks (less common), connect in delta (D). Incorrect connection may damage the motor — verify network voltage before connecting.

What area can it serve at maximum airflow of 7,000 m³/h? At 7,000 m³/h and 4 air changes per hour: maximum served volume = 1,750 m³ → ~580 m² at 3 m ceiling height. At 8 ACH (for spaces with pollutants or high humidity): ~290 m². Use the airflow calculator for precise sizing.

Are the BOX connections compatible with standard ductwork? The BOX connections are compatible with standard circular or rectangular ductwork. Exact flange dimensions are available in the technical data sheet — contact us for the complete dimensional drawing.

Is the VFD included? No — the DD 10/10 in acoustic BOX is supplied without a variable frequency drive. The VFD is ordered separately based on the power and automation requirements of the installation. Contact us for VFD selection assistance.

👉 DD 9/9 M96R — single-phase version for lower airflow 👉 DD 12/12 M9F1 — three-phase version for high airflow 👉 Low-pressure centrifugal fans — complete range 👉 Speed controllers and variable frequency drives 👉 Airflow calculator 📞 +40 722 667 239 — free consultancy for sizing and VFD selection