Abstract: A pulse generator provides a continuous train of electrical pulses of variable frequency, duration and amplitude. The pulse generator includes an adjustable frequency astable oscillator coupled to a monostable pulse generator. An isolation circuit isolates the output of the monostable pulse generator from loading effects to minimize output waveform jitter. A power amplifier receives the isolated pulse signal from the monostable pulse generator and provides output pulses of sufficient energy to simultaneously power continuous and capacitive electrical loads with minimal effect on the pulse generator output pulse waveshape.

Abstract: A coupling circuit receives a high voltage surge wave and injects it into e or more power lines of a single-phase or three-phase power supply circuit, either line-to-line or line-to-ground. The coupling circuit may have a surge coupler including a series connection of a gas tube and a coupling capacitor, and preferably a rectifier, and a shunt resistor for discharging the coupling capacitor. A one-stage or two-stage surge back filter across the power lines protects the power source from the surge wave. Each surge back filter may have series inductors, and shunt surge suppression circuits, which may each include a series combination of a capacitor and a resistor, in parallel with at least one metal-oxide varistor (MOV) or a cluster of MOVs. A grounding suppressor connected from a power line to ground may include gas tubes and/or MOVs, inductors and resistors. Risetime adjusting circuits including resistors and capacitors may be connected between the power lines and/or between the power lines and ground.

Abstract: The utilization of clusters of two or more metal oxide varistors (MOVs) connected in parallel for suppressing surges and transients. Particular embodiments are disclosed for both grounded and ungrounded power systems. Also disclosed are two-stage and multi-stage uni-directional and bi-directional suppressors. Uni-directional means that the suppressor is intended to be placed between a source and a load for the purpose-of preventing voltage surges and transients from being propagated from the source into the load. Bi-directional suppressors are intended to be placed between a source and a load and provide suppression in both directions simultaneously.

Abstract: A generator for subjecting an electrical apparatus to a surge voltage. The generator includes a surge voltage generator, a line isolation surge filter, wave shaping circuits and a rectifier coupling network for coupling the surge voltages in shunt with the power line and the equipment under test.