it doesn't matter what the value of the resistors, he was just showing you what a delta connection is. actually there are two fault conditions for a 3-phase supply when you are running a motor, dropped phase and reversed phase. a dropped phase will not allow the motor to run, a reversed phase (miswiring by getting two of the wires reversed) will cause the motor to run backwards (which can damage some types of machinery). what you really need is something like this: **broken link removed** which monitors the phase voltage and the phase sequence.