Bell Telephone Laboratories

Rudolph Scuderi

Hermann Fickenscher

Richard H Hock

Richard C Ray

Roman Ostapiak

Robert Wilson Michelet

An uninterruptible power supply utilizes a controlled ferroresonant regulator to derive a regulated DC voltage from a primary AC source. A reserve source of DC power is coupled to the output through a DC voltage regulator which is activated when the DC output voltage of the power supply drops below a predetermined threshold.

Uninterruptible power supply with load regulation of standby voltage

An uninterruptable power supply supplies a regulated output by utilizing a ferroresonant transformer. Two independent inputs are connected to the transformer; one input is connected to a commercial AC line signal source, the other input is connected to a battery energized static inverter circuit. The AC line source normally supplies the output power. A phase control system monitors the phase of the regulated output signal and constrains the static inverter to run in phase with the output. The phase and magnitude of the AC line signal are monitored. If the magnitude of the AC line drops significantly, the static inverter is constrained to operate in phase with the AC line signal wherein the inverter and AC line both share to contribute power to the output load. If the AC line signal fails, the static inverter operates independently and supplies all of the output power to the load.

No-break AC power supply

A converter circuit includes an inrush current limit circuit to limit the initial transient surge of inrush current to a power supply upon the initial application of voltage to the power supply input. After the initial start-up transient inrush current surge, the inrush current limit circuit is switched out of the input signal path to reduce power dissipation during normal steady state operation of the circuit. If the input voltage magnitude decreases significantly at any time, the inrush current limit circuit is reset to limit any further current surges.

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Mountain Lakes, NJ, United States of America

Rudolph Scuderi