Q. Why are magnetic field system employed in practical electromechanical energy conversion devices rather than electric field systems?
In case of magnetic field systems energy density is high. The efficiency of electromechanical energy conversion device are high when stored energy is developed by a magnetic field system.
When the energy is an electromechanical conversion is belar the efiiciency the output as well as the performance of the device gets affected also no physical connection in device when magnetic field systems is employed, stored energy density for tolerable electric field strength is low in electric fields.