Abstract
This paper deals with an examination of a method of measurement of exciting force, generated in equipment and its characteristics, when carrying out the control of solid borne sound generated by building equipment. The subject equipment were turbo refrigerators and heat pump chillers, which have considerable exciting force, and, as methods of measurement, examinations were conducted using the direct method and the impedance method. The following conclusions were obtained. (1) The results of measurement by the direct and impedance methods indicate a favorable correspondence. (2) Since the equipment has expansive flat surfaces, exciting force, together with phase shifts, are generated at each of the support points. When concerned with time characteristics of generation, it is better to give consideration to phase differences, however, when concerned with vibration control measures, it is better to express the force, with added energy, which is input to the support points. (3) The exciting force peak modulus for the refrigerator is in the range of 150 dB and that for heat pump chillers is approximately 140 dB. Frequency characteristics of the exciting force indicates a tendency to decrease as the frequency increases in the 63 Hz band or more for heat pump chillers.
