Dot rule for transformers

The dot rule for transformers is a convention used to present the voltage and current relationships and phase. It is a simple rule and therefore sometimes easy to forget, if not used every day. In order to use this rule we need to know two things: (1) The right hand rule for current and fluxes. i.e. If the fingers of the right hand are wrapped around the core in the direction of current flow, then the thumb will point in the direction of the flux. (2)If the current enters a dotted terminal, it causes a positive voltage at the other dotted terminal.If a current leaves a dotted terminal, it induces a negative voltage at the other dotted terminal. For more technical articles and items of interest please visit our website at http://www.signalpro.biz.