Electromagnetic device

A method of forming the electromagnetic device that includes:

• a core support having an exterior surface comprising at least one radial protrusion;
• a tubular magnetic core positioned around a portion of the length of the core support, the tubular magnetic core having an interior surface;
• at least one indent located in the interior surface of the tubular magnetic core, wherein the at least one protrusion is located within the at least one indent to prevent relative longitudinal movement between the core support and tubular magnetic core;
• and a primary coil and at least one secondary coil, each coil positioned around a portion of a length of the tubular magnetic core, the method comprising:
• providing the core support;
• rolling or folding a sheet of magnetisable material around the core support so as to form the tubular magnetic core, wherein the rolling or folding is performed such that the at least one protrusion on the core support penetrates the sheet of magnetisable material to form the at least one indent in the tubular magnetic core.

A linear variable differential transducer comprising:

• a magnetic core;
• a primary coil wound around a first bobbin;
• a first secondary coil wound around a second bobbin;
• and
• a second secondary coil wound around a third bobbin;
• wherein the first, second, and third bobbins are positioned around a portion of a length of the magnetic core, the first bobbin being located between the second and third bobbins;
• and
• wherein there is a gap between first bobbin and at least one of the second or third bobbins.