US 5,448,443 A · Power conditioning device and method

Abstract

A power conditioning device protects sensitive electronics in modern electronic equipment from disruption or destruction caused by transients which can cause both induction and injection currents into the grounding system of the electronic equipment. This device nominally comprises an isolation transformer and a ground impedance between the earth ground connection from a distribution panel and the safety ground connection to the powered equipment. In addition, this device may also comprise a voltage clamping device such as an MOV and a capacitive filter to provide a complete power line conditioner. This device may be used in systems with guarded or driven grounds, or in a system with a high voltage reference to safety ground. In addition, ground conditioning can be added to a Ground Fault Circuit Interrupter (GFCI) to attenuate ground surge currents. The ground impedance may take many forms, including inductors, resistors, diodes, gas tubes, transformers, capacitors, or combinations of these or other components. The ground conditioning device may be used on power systems of different voltages and frequencies, including three phase power systems.

Claims22

Dependent claims

A device for suppressing transient currents in a three-wire power distribution system powering a grounded electrical load, the distribution system providing alternating current power at a reference frequency and separate voltage and reference potentials, and providing a reference ground, comprising the combination of:

isolation transformer means having primary and secondary windings providing respective input and output terminals,
said input and output terminals being magnetically coupled while being isolated from direct electrical connection to each other,
said input terminals being electrically coupled to the alternating current power, the input terminals respectively being comprised as voltage and reference inputs and said output terminals respectively being comprised as voltage and reference outputs,
said output terminals being electrically coupled to the electrical load, the isolation transformer then isolating the electrical load from the power distribution system, and
the electrical load around and the reference output being electrically coupled together as a safety ground;
and
electrical inductive impedance means, electrically coupled in series between the safety around and the reference around, for providing electrical isolation between said safety ground and said reference ground.

4 more elements

Dependencies are inferred from the claim text.

Power conditioning device and method

Life of this patent

Power conditioning device and method

Life of this patent

Abstract

Claims22