Explanation: Electromagnetic torque = isirdMsr/dθr and if either is or ir =0, then Te=0. 12. All practical electromechanical energy conversion devices make use of the magnetic field rather than the electric field as the coupling medium.This is because
A. electric field systems present insulation difficulties
B. electric field systems have more dielectric loss than the magnetic loss, for the same power rating of the machine
C. in electric field systems, for normal electric field strength, the stored energy density is high
D. in magnetic field systems, for normal magnetic flux density, the stored energy density is high
Answer:A
Explanation: Electromagnetic torque = isirdMsr/dθr and if either is or ir =0, then Te=0. 12. All practical electromechanical energy conversion devices make use of the magnetic field rather than the electric field as the coupling medium.This is because
A. electric field systems present insulation difficulties B. electric field systems have more dielectric loss than the magnetic loss, for the same power rating of the machine C. in electric field systems, for normal electric field strength, the stored energy density is high D. in magnetic field systems, for normal magnetic flux density, the stored energy density is high
Explanation: As the energy storing capacity of the magnetic field is higher, magnetic field as coupling medium is most common in electromechanical energy conversion devices. Sanfoundry Global Education & Learning Series – Electrical Machines.