Load-Measuring Apparatus for Agricultural Machinery Engineering Problems

Abstract

The load measuring apparatus, which we used, consists of a transducer (such as a torque pickup) using electrical resistance strain gages, two electronic amplifiers, a direct-ink oscillograph, an electro tachometer and two event markers. They have proved to be satisfactory, to some extent, in field test to determine load requirements in agricultural machines. However, the engineer may need to be familiar with the principles, characteristics, and handlings of each elements of the apparatus.
In using this apparatus for farm machine testings, we have encountered with various problems.
Some problems have been found to be as follows:
(1) One of most common troubles in using the torquemeter was the hash voltage caused by the bad conditions of brush contacts with sliprings of the torque pickup.
(2) The frequency range of 50 C P S, in which the direct-ink oscillograph has responded, will give accurate results and it will be almost enough for most measurements required on farm machinery. But the chart paper driving device should be made more accurately.
(3) In order to minimize the hum effect, frequentry encountered in usiug the electro-tachometer, we have successfully applyed capacitor.
(4) Two event markers designed in our institute are used to record time and to check speed. Their principles and circuits are very simple and there has been not any problems.
(5) The effectiveness of described apparatus will depend upon how to apply the transducer, or what types of transducer will be used. We will coutinue study on these problems.