ECN Forum Forums General Topics of the Trade General Discussion Area Transformer inrush

Once the transformer is started there is always a residual magnetic field to control the incomming current. IE it opposes the incomming rush of current. When a transformer is energised there is no magnetic opposition to the flow of current hence the Inrush. Once the transformer has an established magnetic field the 0 crossing of the AC does not cause a complete collapse of the opposing EMF and magnetic field.