Synchronous Motor ExcitationPrior to understanding this synchronous motor excitation, it should be remembered that any electromagnetic device must draw a magnetizing current from the AC source to produce the required working flux. This magnetizing current lags by almost 90o to the supply voltage. In other words, the function of this magnetizing current or lagging VA drawn by the electromagnetic device is to set up the flux in the magnetic circuit of the device.The synchronous motor is doubly fed