Abstract
A mathematical model is developed to estimate the pressure response of an insulated electric air compressor. A pressure switch is modeled as a comparator, and the electric motor as an amplifier. It is assumed that compressed air is a perfect gas when applying the isentropic process. In addition, the effect of step, ramp, and sinusoidal functions of disturbance signals on air pressure have been studied. A good agreement was obtained when comparing the predicted results with the measured values obtained from the experimental test that was done using a (1.32 kW, 23 liters, and 8 bar) electric reciprocating air compressor. In addition, the same behavior of the predicted results was obtained when compared with the results of a previously published article. It was found that the time constant of this control system is directly proportional to the value of the spring constant that is inserted inside the pressure switch and with the volume of the air storage vessel, and it is inversely proportional to the gain of the amplifier and with the effective cross-sectional area of the pressure switch diaphragm, and it is independent of the value of operating pressure set point. In addition, when the value of the disturbance signal is positive, it will increase the output pressure response, and when it is negative, it will decrease it.
Tags:
Papers