RS20070339A - Procedure and device for measuring torque of a direct current (dc) motor with independent and parallel excitation - Google Patents

Abstract

Procedure and device for measuring torque (M) of direct current engines with independent and parallel excitation (MJS), is achieved as shown in Fig. 1 by coupling brushes (Č) set at the endings of a shaft (V) of a machine rotor, an insulated conditioner (IKU) for measuring an alternating voltage (u=u(t)) between brushes and other components. Therewith accurately defined is the technical problem of measuring the torque (M) solved very precisely and reliably within a relatively short time and by more positive technical economic effects compared to the known solutions comprised in the state of art. Measuring gives instantaneous value of alternating voltage at the chosen time periods from (10-50) μs, which as a complex period function of time expands into Fourier series as harmonics, where first of all by determining the predominant harmonics, and then the quotient of that harmonics and the chosen time for measuring (t) during unknown and nominal loading is obtained the frequency of the equivalent of postoperiodic sinusoidal function of time for that voltage, and finally according to the equation (7) the required torque (M) of considered engines (MJS).