Evaluation of energy saving resource in electric drive of blower fan with two-speed induction motor

The paper covers energy saving reserves at frequency performance control of a blower fan with two-speed induction motor of the hot-water boiler KVGM-100. A new method of performance control is offered for draught systems; the method is based on switching of frequency converter from high-speed winding to lowspeed winding and to the throttle control within the speed ranges close to the rated speed values for these windings. The paper presents diagram of the device providing the implementation of this method. The research group constructed natural and artificial characteristics of the blower fan and the main line when the motor operates on the high-speed winding at the throttle and frequency control. The comparative analysis of the power loss was carried out, and it was found that application of frequency control provides energy saving of up to 42 % compared with the throttle control. The comparative analysis of power consumption was carried out after implementation of the developed method under conditions of the same operation time on the windings of high and low speeds. As a result the authors claimed the effective decrease of power consumption from 22 % to 35 % depending on the combination of performance control methods. It was proved that the frequency control on the low speed winding does not result in equivalent loss of efficiency and consequently in the increase of the consumed power of the blower fan. It is noted that the technical and economic effect is provided due to the resource-saving and reliability improvement of the draught mechanisms while the power consumption remains the same. The authors offer some recommendations on the application of the developed method.