Abstract: A method for determining the nature of a ground fault in a floating direct voltage load powering context includes measuring the load voltage and the current at a nominal balance point, both before and after closing a circuit to the load. The fault resistance and the fault voltage are determined as the solution to an equation in two unknowns given the conditions before and after application of load voltage or at least precharge.

Abstract: The increasing use of electrically powered vehicles has created a need for inexpensively and effectively measuring high currents for motor control, as for example digital motor control. Because the high operating voltages of traction motors, the motor current sensors should be non-contacting. A non-contacting current sensor having a rated capacity significantly less than the motor winding current is coupled to one or more of the conductors of a paralleled multiconductor motor winding for sensing the current in that conductor. The paralleled electrical motor conductors are paralleled by additional similar conductors, so that only a fraction of the current to be measured flows through the conductor(s) associated with the sensor. The current sensor elements may be mounted on a pc board, which supports the elements, and also has one or more printed patterns which define conductors associated with the sensor.