Patent ID: 6798627
Filing Date: 2004-09-28
Classification: H02P

Abstract:
An overload protection apparatus for protecting an engine-generator set from damage, the overload protection apparatus including:a load vower sensing circuit, including an input configured for coupling to an engine-generator set load, and an output providing a load power signal measuring an indication of power delivered from the engine-generator set to the load; and a voltaae regulator circuit, including an output configured for coupling to a control input of a generator exciter circuit to control a voltage delivered from a generator to the load, and including an input coupled to the load power sensing circuit output to receive the measured load power indication, the voltage regulator configured to decrease a magnitude of the voltage delivered from the engine-generator set to the load when the measured load power indication reaches a predetermined maximum value to substantially prevent the load power delivered from the engine-generator set to the load from exceeding a maximum load power value; and in which the load power sensing circuit includes: a load voltage sensing circuit, including an input configured to be coupled to the load, and an output providing a load voltage signal indicative of a load voltage; a load current sensing circuit, including an input configured to be coupled to the load, and an output providing a load current signal indicative of the load current; and a load power calculation circuit, including a first input coupled to the load voltage sensing circuit output to receive the load voltage signal, and a second input coupled to the load current sensing circuit output to receive the load current signal, and coupled to the load power sensing circuit output to provide the load power signal based on a multiplication of the load voltage signal and the load current signal and a power factor calculated using a phase angle between the load voltage signal and the load current signal.