Minimization of the Basic Electric Consumption by the Direct Current Motor of the Slabing Rolling Mill in Start-Braking Regimes

Purpose. Minimization in start-braking regimes of the basic electric consumption of a direct current (DC) motor with independent excitation, driving a horizontal rollers of a metallurgical slab mill, and obtaining analytical dependencies to find the optimal type of speed change trajectories (tahograms) and optimal durations of acceleration and deceleration times, minimizing the electric consumption of the motor. Methodology. Using the methods of variation's calculation, mathematical analysis and similarity, the optimization of the different form and the duration of the times of the startbraking regimes of the motor was carried out. The energy efficiency of which was researched, using the method of computer simulation. Results. The minimization of electric consumption in the start-braking regimes of a DC motor, which drives the horizontal roller of the slab metallurgical mill, has been carried out. The mentioned minimization of electric consumption is achieved by optimizing the form of the tahograms and the duration of the acceleration and deceleration times of this motor. A quantitative comparison of the achieved minimum electric consumption by the motor with known tahograms of a different form and other (different from optimal) durations of acceleration and deceleration times has been performed. Originality. The "U"-shaped view of the electric energy, consumed by the DC motor in the start-braking regimes, is established for the change of the duration of the acceleration and deceleration times. Analytical dependencies are obtained for the optimal form of tachogram in start-braking regimes, which minimize the electric consumption of the motor in these regimes for set acceleration and deceleration times. Analytical dependencies are proposed for calculating the optimal durations of acceleration and deceleration times, that minimize the electric consumption of the motor in these regimes, in relation to two zones of operation of a slab metallurgical mill: for the absence and presence of metal in the rollers. Practical value. In relation to two DC motors, that drive the horizontal rollers of a slab metallurgical mill at the Zaporizhstal plant, the decrease in electric consumption by these motors and the expected annual energy saving from using the proposed for them energy-efficient tachograms and optimal durations of acceleration and deceleration times are quantitative defined.