Electrodynamometer

An electrodynamometer is used in voltmeters and ammeters and here we are making use of the heating effect of ac current. Electrodynamometer can be used even at low audio frequency power line frequencies. It gives excellent response at normal power line frequencies. With a slight modification of permanent, magnetic moving coil arrangement, we can design electrodynamometer. Here moving coil rotates within the magnetic field. The magnetic field is generated by the current which is to be measured. In an electrodynamometer, shield lamination is employed for the protection of the device from stray and strange magnetic fields. Aluminium air vanes in motion in a sector shaped chamber are used for providing damping. The transfer properties of the electrodynamometer become apparent while comparing the effective value of AC and DC in terms of their heating effect.