The Rosenberg Centrifugal Fans with a free-running impeller of the range DKN_ were designed to install in appliances such as Air Handling Units (AHU) and hygienic and clean room filter units. During the development of this unit with a backward-curved impeller without scroll casing, special attention was paid to optimize the efficiency over a wide characteristic curve while still maintaining high performance and an optimum sound power level. The fans are suitable to handle air and other non-aggressive gases or fumes. The motors are available with the latest three-phase IEC standard motors or standard NEMA Premium Efficiency motors. Moreover, different features, such as explosion-proof or hazardous locations, are available, depending on the application. Depending on fan construction, the following two fan types are available: DKNB and DKNM.
Fan module with mounting stand.
The Inlet cone is mounted and adjustable to the correct depth.
The complete unit can be installed with vibration dampers or springs.
Fan with NEMA PE motor, respectively with IEC standard motor; type IMB3.
Fan module without mounting stand.
The Inlet cone is mounted and adjustable to the correct depth.
Fan with NEMA PE motor, respectively with IEC standard motor, type IMB5.
The impellers with seven backward-curved blades are made of aluminum (AIMg3) and are statically and dynamically balanced with hubs according to quality level G6.3 DIN ISO 1940.
The impellers can be supplied with a special coating for harsh environments if needed.
The direction of rotation of the impellers when viewed from the inlet side is clockwise.
The wrong direction of rotation can overload the motor; therefore, it is essential to check the direction of rotation before the initial operation.
The inlet cones are made of galvanized sheet steel.
They are fluidic optimized and offer good airflow of the impeller.
The optimal immersion depth of the impeller is shown according to dimensional drawings.
Airflow control and monitoring can be done through a circular lead on the inlet cone.
Rosenberg’s DKNM and DKNB fans are equipped with NEMA Premium Efficiency motors, 230V/460V/60Hz.
They can be supplied with the following options: partially or totally enclosed, explosion-proof, etc. In addition, different voltages are available and a different number of poles for different nominal speeds. Further information on the drive motor, motor safety, and speed control can be found in the individual special description of each ventilator type.
The wiring box of the motor is easily accessible. The motor must be connected according to the wiring diagram and in conformity with valid regulations and local laws.
When operating with a frequency transformer, please refer to the operation manual.
The installation-specific optimal adjustment for the required operating point can only be released with a suitable speed control system. The speed is adjusted by changing the frequency with a frequency converter. The maximum frequency of the motor must be observed. At higher frequencies than fmax, the motor will thermally overload, and the temperature sensor will react after a certain increase in temperature. The cut-off frequency adjustable on the frequency converter is 50Hz for IEC standard motorsand 60Hz for NEMA motors. In case of emergency service or failure of the frequency converter, all fans can be operated at 400V, 50Hz, and at 460V, 60Hz, main supply. When a frequency converter operates the motors, the maximum speed of voltage increase of 500V/μs should not be exceeded.
Depending on the type of frequency converter and the length of the cable between the motor and frequency converter, additional components must be provided (e.g., a sinus filter).
The Rosenberg Centrifugal Fans with a free-running impeller of the range DKN_ were designed to install in appliances such as Air Handling Units (AHU) and hygienic and clean room filter units. During the development of this unit with a backward-curved impeller without scroll casing, special attention was paid to optimize the efficiency over a wide characteristic curve while still maintaining high performance and an optimum sound power level. The fans are suitable to handle air and other non-aggressive gases or fumes. The motors are available with the latest three-phase IEC standard motors or standard NEMA Premium Efficiency motors. Moreover, different features, such as explosion-proof or hazardous locations, are available, depending on the application. Depending on fan construction, the following two fan types are available: DKNB and DKNM.
Fan module with mounting stand.
The Inlet cone is mounted and adjustable to the correct depth.
The complete unit can be installed with vibration dampers or springs.
Fan with NEMA PE motor, respectively with IEC standard motor; type IMB3.
Fan module without mounting stand.
The Inlet cone is mounted and adjustable to the correct depth.
Fan with NEMA PE motor, respectively with IEC standard motor, type IMB5.
The impellers with seven backward-curved blades are made of aluminum (AIMg3) and are statically and dynamically balanced with hubs according to quality level G6.3 DIN ISO 1940.
The impellers can be supplied with a special coating for harsh environments if needed.
The direction of rotation of the impellers when viewed from the inlet side is clockwise.
The wrong direction of rotation can overload the motor; therefore, it is essential to check the direction of rotation before the initial operation.
The inlet cones are made of galvanized sheet steel.
They are fluidic optimized and offer good airflow of the impeller.
The optimal immersion depth of the impeller is shown according to dimensional drawings.
Airflow control and monitoring can be done through a circular lead on the inlet cone.
Rosenberg’s DKNM and DKNB fans are equipped with NEMA Premium Efficiency motors, 230V/460V/60Hz.
They can be supplied with the following options: partially or totally enclosed, explosion-proof, etc. In addition, different voltages are available and a different number of poles for different nominal speeds. Further information on the drive motor, motor safety, and speed control can be found in the individual special description of each ventilator type.
The wiring box of the motor is easily accessible. The motor must be connected according to the wiring diagram and in conformity with valid regulations and local laws.
When operating with a frequency transformer, please refer to the operation manual.
The installation-specific optimal adjustment for the required operating point can only be released with a suitable speed control system. The speed is adjusted by changing the frequency with a frequency converter. The maximum frequency of the motor must be observed. At higher frequencies than fmax, the motor will thermally overload, and the temperature sensor will react after a certain increase in temperature. The cut-off frequency adjustable on the frequency converter is 50Hz for IEC standard motorsand 60Hz for NEMA motors. In case of emergency service or failure of the frequency converter, all fans can be operated at 400V, 50Hz, and at 460V, 60Hz, main supply. When a frequency converter operates the motors, the maximum speed of voltage increase of 500V/μs should not be exceeded.
Depending on the type of frequency converter and the length of the cable between the motor and frequency converter, additional components must be provided (e.g., a sinus filter).
EC (Electronically Commuted or Electronically Controlled) motors are electric motors which have permanent magnets on the rotor and use electronics to control the voltage and current applied to the motor.
EC motors have no brushes, so they avoid the sparking and short life of brushed motors. Because they have electronics controlling the stator and do not need to waste power inducing the rotor field, they give better performance and controllability and run cooler than induction motors (for small motors, at least; high horsepower 3 phase induction motors can be very efficient). EC motors are used today in many fractional-horsepower applications where high motor efficiency, reliability, and/or controllability are desired.
EC motors are very high efficiency and maintain a high efficiency level even at part speed. This means that in most cases, they use from less than one-third to one-half of the electricity needed by the traditional "shaded pole" induction motors used in the ventilation and refrigeration industries, which in turn translates into lower operating costs and short payback periods.
EC motors’ high efficiency also means that the motors run “cool” and dramatically reducethe amount of waste heat produced. Reduced waste heat at the evaporator motor level also typically results in reduced operation at the compressor level, which allows further energy savings. Further, running cooler improves the life of highly loaded motor parts like windings and bearings.
EC motors also have a wider operating range than traditional induction motors, which means that one ECM motor can replace several induction motor models. In this way, the number of models required by a typical customer is significantly decreased, which reduces and simplifies inventory. This is the main reason why ECM product lines usually include fewer motor models than their induction counterparts.
In terms of speed control and features, because the motor’s operation is controlled by software, EC motors allow customers to optimize and integrate the motor, fan, and controller with the application and to include features like data communications, constant volume control, variable speed, etc.
EC motors are also quieter than traditional inefficient motors, have longer design life, and require less maintenance.
