Human Subjects Protection by Monitoring the Stabilized Supply Voltages of the Medical Equipment

Abstract

This study addresses a sensitive topic, namely how human subjects undergoing medical procedures can be protected by means of medical electrical equipment. A solution to this problem is to monitor the stabilized electrical supply voltages of the medical equipment. The net effect of the proposed protection is the automatic disconnection of the medical equipment from the alternating voltage network supplying the medical equipment. This disconnection must be done without using electrical switching devices that contain electrical contacts that can generate electrical sparks. This is because most of the time the medical equipment is placed in an area where pure oxygen or other combustible gases predominate. Therefore, only static relays are used in this case. The realized electronic module has been tested in the laboratory and is capable of automatic disconnection of any medical equipment from the 230 V~, f = 50 Hz AC power supply in the case of major faults, which can be caused by accidental overvoltage on the electric energy supply lines, accidental overtemperatures, transient overvoltage which are propagated during storms, etc. This study presents the transient phenomena that occur in the immediate vicinity of the monitored voltages range. Finally, a solution for simultaneous monitoring of four electric voltages and/or currents is presented.