Low magnetic electric motor

Low magnetic or nonmagnetic electric[1] motors are used on board mine countermeasures vessels, minehunters, minesweepers and specific types of submarines.

A significant part of these magnetic stray fields emanate to the outside of the electric motor housing and can be measured and/or detected.

Methods of measurements and acceptance criteria are defined in the American military MIL-STD-740-2(SH)[18] and the British Defence Standard 02-813[19] Mechanical unbalance of the rotor will generate vibration.

The vibration will result in structure borne noise, as well as unwanted acceleration forces or resonance, which eventually will harm or damage parts of the electric motor.

A dedicated rigid design will allow electric motors to withstand these environmental impacts and provide sufficient active hardening.

Due to the nature of naval applications, equipment on board of mine countermeasures vessels and submarines may be subject to underwater explosions.

Shock testing on equipment is performed by specialist institutes, such as TNO,[25] NTS Navy, Thales-ECC or QinitiQ.