Abstract: An apparatus for monitoring the temperature of an inaccessible portion of an electrical current carrying device that cannot be directly measured easily comprises circuits for establishing a reference temperature value in the vicinity of the current carrying device and measuring the power dissipated in the current carrying device, a digital computer having ports for inputting the reference temperature value, the power dissipated in the current carrying device, the thermal resistances and thermal time constants of the thermal model simulating the current carrying device to the reference temperature, and a program stored in the digital computer for continuously calculating a differential temperature based upon the power dissipation and thermal model and adding the reference temperature thereto.

Abstract: The present invention pertains to a multiphase pulse width modulator which allows for continuous conduction of current through each winding of a multiphase motor at all times of the motor's operation. In a preferred embodiment, the multiphase pulse width modulator is for an N-phase motor, where N.gtoreq.3. The multiphase pulse width modulator is comprised of a clock for producing a switching frequency. The modulator is also comprised of means for providing N phase displaced signals to the respective N phases of the N phase motor such that the signals allow for continuous conduction of current through each winding in the motor at all times of the motor's operation. The providing means is connected to the clock for receiving the switching frequency, and connected to the N phases of the N phase motor to provide the N signals to the respective N phases of the N phase motor.