Acta Univ. Agric. Silvic. Mendelianae Brun. 2014, 62(5), 1007-1014 | DOI: 10.11118/actaun201462051007

Measurement of Heat Losses on The Milking Machine Electric Motor at Various Regulations of Vacuum Using Methods of Thermal Imagery

Jan Kudělka, Jiří Fryč, Petr Trávníček

Department of Agriculture, Food and Environmental Engineering, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic

To ensure the desirable vacuum in the milking machines, use is currently made predominantly of rotary vacuum pumps. These vacuum pumps are driven by a squirrel-cage induction motor. Until recently, the vacuum in the system to achieve the required value was controlled by a main control valve sucking in ambient air into the system. During the milking process itself and during other activities (flushing, sanitation), this control method consumed a large amount of electricity. The technical solution to electricity demand reduction was introduced with the emergence and development of frequency converters. The frequency converters control the operation of the asynchronous electric motor so that the actual delivery of the vacuum pumps equals the volume of air sucked into the vacuum pipe. The motor supply by the frequency converter brings about a host of adverse phenomena. This paper is dedicated to motor heating and heat losses on the surface of the electric motor at different regulations of vacuum in milking machines. The objective of the paper is to determine the immediate specific heat flows along the surface of the electric motor of the milking machine during milking using a control valve regulation and a control using the frequency converter, and compare the resulting value. The specific heat flows were determined by means of a non-traditional method of temperature field measurement using a system of thermal imagery. The calculated and measured data obtained from both these systems were statistically evaluated and compared. Use was made of a milking machine located in the cooperative Hospodářské obchodní družstvo (HOD) Jabloňov.

Keywords: milking machine, rotary vacuum pump, electric motor, control valve, frequency converter, thermal camera, heat losses

Grants and funding:

This project is implemented with the support of the Internal Grant Agency of the Faculty of Agronomy, Mendel University in Brno, TP 8/2014. The project was also employed as part of the innovation of the subject taught in the field of TO, ZS, ARI system for the management of pilot biomass stations Biomass and bioenergy transformation (IN2140331).

Published: December 2, 2014  Show citation