... Field Systems Many electromechanical devices have multiple electrical terminals. Measurement systems: torque proportional to two electric signals; power as the product of voltage and current. ... charge in the presence of electric and magnetic fields. F q()BvEqF×+= (3.1) F : newtons, : coulombs, : volts/meter, q EB: telsas, : meters/second v In a pure electric- field system, ... energy-storage mechanism. – Electrical losses: ohmic losses… – Mechanical losses: friction, windage… Fig. 3.3(b): a simple force-producing device with a single coil forming the electric terminal,...