Reduction of the turbine torque measurement error by determining the settling time of oscillatory processes in the electric machine brake

Abstract

An analysis of transients in electric machine brake, which are used in research of hydraulic
machines parameters in specialized hydro-turbine laboratories or in other industries where it is
necessary to measure torque in this way, is presented in the article.
It was established that an increase in the accuracy of torque measurement when using an
electric machine brake is associated with a more accurate accounting of electromagnetic transient
processes in electric balancing machines at changes and fluctuations of drive parameters (for
hydraulic systems it is flow rate and head) and determination of the exact time of the stationary
mode setting, in which residual oscillatory processes will not contribute significantly to the overall
error.
The analytical dependence of the system settling down time on the parameters of the electric
machine brake, namely on the electromagnetic and mechanical time constants caused by design
features of the electric machine brake, was obtained.
Experimental researches were carried out which allow drawing conclusions about the
adequacy of the proposed equations and make it possible to use them in practice, in particular, when
carrying out hydraulic machines model tests with the aim of reducing the error in measuring the
torque on the shaft and determining the hydraulic machine efficiency.