Patent ID: 7489483

Claim:
A circuit for determining an electrical problem at a motor, said circuit comprising: a first voltage divider circuit connected to a first terminal of the motor via a first conductor; a first test point disposed on the first conductor; an input line connected to said first voltage divider circuit to enable a first supply voltage to be applied to said first voltage divider circuit and cause a first test voltage to be applied to the first conductor, the first test voltage being available at said first test point for measurement if a short circuit does not exist along the first conductor; a second voltage divider circuit connected to a second terminal of the motor via a second conductor; a second test point disposed on the second conductor; an input line connected to said second divider circuit to enable a second supply voltage to be applied to said second voltage divider circuit and cause a second test voltage to be applied to the second conductor, the second test voltage being available at said second test point for measurement if a short circuit does not exist along the conductor; a pair of switches connected at a common terminal to the first and second conductors, respectively, said pair of switches each having a first and second selectable terminal, a first voltage source conductor connected to the first selectable terminals of said pair of switches; a third switch connected to the second selectable terminals; a second voltage source conductor connected to one side of said third switch, said third switch selectability being switched to apply a voltage on said second voltage source conductor to the second selectable terminals.