Electrical resistivity tomography Electrical resistivity tomography Electrical resistivity tomography (ERT) or electrical resistivity imaging (ERI) is a geophysical technique for imaging sub-surface structures from electrical resistivity measurements made at the surface, or by electrodes in one or more boreholes. If the electrodes are suspended in the boreholes, deeper sections can be investigated. It is closely related to the medical imaging technique electrical impedance tomography (EIT), and mathematically is the same inverse problem. In contrast to medical EIT, however, ERT is essentially a direct current method. A related geophysical method, induced polarization (or spectral induced polarization), measures the transient response and aims to determine
Armature (electrical) design of the machine and its performance, affecting such factors as commutation in a DC machine or the waveform of an AC machine. Armature wiring is made from copper or aluminum. Copper armature wiring enhances electrical efficiencies due to its higher electrical conductivity. Aluminum armature wiring is lighter and less expensive than copper. Armature (electrical) In electrical engineering, an armature is the power-producing component of an electric machine. The armature can be on either the rotor (rotating part) or the stator (stationary part) of the electric machine. The armature interacts with the magnetic field (magnetic flux) in the air-gap; the