Magnetic field sensors could be used, but measuring the magnetic field directly with magnetic field sensors is difficult. Multiple sensors would be needed to compensate for orientational sensitivity of the sensors relative to the magnetic field.

The present application provides a new and improved device protection mechanism in high magnetic fields which overcomes the above-referenced problems and others.

In accordance with one aspect, an apparatus for protecting electromechanical components in a magnetic field includes a current sensor and a current switch. The current sensor senses current draw in excess of safe operating conditions by a protected device. The current switch, connected to the current sensor and interposed between a power supply and the protected device, interrupts the current flow to the protected device based on the current draw sensed by the current sensor.

In accordance with another aspect, an MRI scanner room power supply includes an MRI scanner, a medical device and an apparatus for protecting the medical device. The MRI scanner generates a magnetic field of at least 10,000 gauss. The medical device is used in conjunction with a patient to be scanned by the MRI scanner. The apparatus interrupts the current flow to the medical device in response to being moved into sufficient proximity to the MRI scanner that ferrous components in the medical device saturate.

In accordance with another aspect, a method of protecting an electromechanical device in a magnetic field includes sensing current flow to a device which has electromechanical components which saturate in a magnetic field and draw current above a threshold. The current flow is interrupted to the device in response to the sensed current exceeding a threshold.