A Reed blade, commonly known as an armature, is one of the two flattened parts that form the cantilever and current carrying parts of a reed switch. Two of these reed blades are hermetically sealed at either ends of a glass tube to form a Reed Switch.
In electrical engineering, an armature is the component of an electric machine which carries alternating current. The armature windings conduct AC current even on DC machines, due to the commutator action (which periodically reverses current direction) or due to electronical commutation, as in brushless DC motors. The armature can be on either the rotor (rotating part) or the stator (stationary part), depending on the type of electric machine.
The armature must carry current, so it is always a conductor or a conductive coil, oriented normal to both the field and to the direction of motion, torque (rotating machine), or force (linear machine). The armature's role is twofold. The first is to carry current across the field, thus creating shaft torque in a rotating machine or force in a linear machine. The second role is to generate an electromotive force (EMF).
In the armature, an electromotive force is created by the relative motion of the armature and the field. When the machine or motor is used as a motor, this EMF opposes the armature current, and the armature converts electrical power to mechanical power in the form of torque, and transfers it via the shaft. When the machine is used as a generator, the armature EMF drives the armature current, and the shaft's movement is converted to electrical power. In an induction generator, generated power is drawn from the stator.
A growler is used to check the armature for shorts, opens and grounds.