International Business Machines Corporation

William M Lorenz

King M Chu

Tuan D Ngo

Prabjit Singh

Gerald J Fahr

Gerard Vincent Weber, Jr

Andrew Rybak

Kwok M Soohoo

Joseph W Bogdanski

William T Winkler

John P McConnell

A system for injecting noise signals onto power generated by a power source comprising: a voltage source; a device under test having a power input in operable communication with the noise introduction apparatus; and a noise introduction apparatus interposed between the power source and device under test in operable communication with the voltage source, the noise introduction apparatus comprising, a switching device configured to provide a low impedance conductive path when commanded, and a current limiting device in series with the switching device, the current limiting device configured to provide a low impedance conductivity for a selected current and a selected duration. The switching device and current limiting device cooperate to shunt the voltage source to the power input.

Method and apparatus for evaluating susceptibility to common mode noise in a computer system

The power supply of equipment being tested for common mode noise problems is connected to a source of power with the power and neutral input terminals of the power supply isolated from the power ground. Recorded common mode noise signals are then inserted between the power supply's neutral input terminal and power ground to produce problem conditions. When the cause of the problem conditions are identified, steps are taken to eliminate the condition.

Apparatus and method for testing computer equipment for susceptibility to neutral to ground noise

A current limiting circuit for limiting current surges caused by device turn-on and by input line voltage surges. The circuit has a current sensor for sensing current surges and causing the current to be routed through a current limiting device, such as a resistor. The current sensing circuit senses both over current and normal current conditions and resets the current limiting switch as appropriate. The use of a current sensor as opposed to a sensor for turn-on conditions or voltage levels provides actual control of the current thereby protecting the electrical device during the first application of power and from AC line voltage surges.

Current limiting device

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Saugerties, NY, United States of America

William M Lorenz