Blauberg AC Zentri-PAC Backward Curved Plug Fan with Casing

Responding to the popular demand and customer feedback we have created a special series of centrifugal fans which feature backward-curved blades and benefit from improved impeller design and reliable high-performance EC motors.

The new series includes the most popular fan models, which comply with all modern aerodynamic and energy efficiency requirements with the impeller diameter ranging from 133 mm to 250 mm. The impeller is made of a composite high-tech plastic material with fibreglass reinforcement elements for higher rigidity and stress resistance.

Specially profiled blades are the result of extensive CAD design and long hours of wind tunnel testing help reduce airflow losses and improve the aerodynamic characteristics of fans. Smooth and uniform airflow spread reduces operating noise.

For further improvement of the ease and convenience of fan installation Blauberg Motoren has come up with the latest solution, which enables using Zentri-PAC fans with Plug Fan type casings produced in-house.

ADVANTAGES OF AC MOTORS:

• Permanent speed at various loads.
• Resistance to short-term mechanical overloads.
• Easy structure.
• Easy start-up.
• Higher cos Ø and efficiency compared to electric motors with phased rotor.

Asynchronous electric motors consist of two basic components, the stator and the rotor. The stator is a fixed motor component. On the inner side the stator has some slots for laying of three-phase cable winding that is powered by three-phase current. The rotor is a rotating part of the motor and also has slots for inserting the cable winding. The rotor and the stator are assembled of separate 0.35-0.5 mm thick electrotechnical steel pressed plates.

Separate plates are insulated from each other with a varnish layer. The air gap between the stator and the rotor is kept as low as possible: 0.3-0.35 mm for low capacity machinery and 1.0-1.5 for more powerful machinery.

Depending on the rotor design the asynchronous motors are available in short circuit modification and phased modifications. Short circuit motors are the most widely used motors because of their simple design and easy operation. The threephase stator winding is inserted inside the slots and consists of a number of interconnected coils. Each coil consists of one or several turns which are insulated against each other and against the slot walls.

The design of the asynchronous electricmotor with external rotor is similar to that of the standard asynchronous electric motor. The only difference is the position of the rotor. The electric rotor motor is located inside the stator winding and the stator with turns is located in the electric motor center. This configuration provides a compact size of the ventilation unit. The electric motor shaft is carried by ball bearings fixed inside the stator and the impeller is fixed in the rotor casing. Such a design provides air cooling of the electric motor which makes it applicable for a wide temperature range. The electric motors are assembled with the impellers and are subjected to static and dynamic balancing in compliance with DIN ISO 1940. The motors have an integrated overheating protection with automatic restart.

All the motors have 100 % controllable speed range. Speed control is performed with a transformer or electronic devices. Explosionproof motors are controlled exclusively by transformers within 25% up to 100% of the rated voltage range. Speed control is performed by voltage change whereas the frequency in the grid remains the same. The electric motor speed is smoothly decreased as power voltage drops or is increased as power voltage rises. The motor can also be controlled with a frequency converter