Rosenberg is introducing a family of compact, radial fans with free-running impellers and variable speeds that combine electronically commutated external rotor motors with newly developed integrated power electronics. Designated by model numbers GKHR and GKHM, the new fans’ long-life, low-temperature “brushless” DC motors are controlled by maintenance-free electronic circuitry. GKHR fans are motorized impellers, mounted and balanced, that may be provided with or without an inlet cone. GKHM fans are complete fan modules. The fans’ external rotor design and high power density make them ideal for use in ventilation and air conditioning applications. With reduced mechanical content, the fan motors run cooler and quieter, require little or no maintenance and can be speed-controlled using an external potentiometer or 0-10V PWM signal. Unlike conventional DC motors, the new Rosenberg EC motors deliver highly efficient, low-noise performance without using collectors and carbon brushes that wear out and shorten motor life. Also in the new models, both the power supply and control leads connect directly at the motor, simplifying installation. In pressure control applications, the EC motors can be direct connected to a pressure sensor. In master-slave designs, the pressure controlled output of the master fan controls slave unit speeds. Networking is easy by linking fan motor electronics to a computer using an RS485 interface.
