The devices 80 include ventilators, injectors, infusion pumps, monitoring devices such as blood pressure monitors, CO₂ monitors, anesthesia gas monitors, and the like as well as ancillary devices such as printers, workstations, and entertainment devices. The devices 80 include any device which uses a motor or a solenoid or other ferrous components. The power source 90 may be incorporated into the device 80, separated as an individual component, or a plug which uses a standard outlet for power. Some power sources 90 include an AC/DC converter. The power requirements are specific to the device 80. The effect of the magnetic field 40 on the device is determined with a hysteresis or BH curve. The current drawn by the device 80 continues to increase as the device 80 experiences an increasing magnetic field 40 until a maximum is reached when the ferrous core or other components saturate. At the saturation point the device 80 is susceptible to damage or burn-out of electromechanical components due to the excess current draw. A protection mechanism 100 is interposed between the device and the power source to protect the device from damage due to a magnetic field induced excessive current draw.

An embodiment of the protection mechanism 100 determines the current draw of the device as the device 80 experiences an increase in the magnetic field 40 intensity. When the device 80 is near saturation, the protection mechanism interrupts the current from the power source 90. The power remains interrupted while the device 80 is near saturation. As the device 80 moves away from the magnetic field 40 or the magnetic field 40 decreases in intensity, the power automatically resumes.