Automatically switching multiple input voltage power supply
First Claim
1. An automatically switching DC power supply comprising:
- an AC input voltage connection;
a transformer with two primary windings rated for the same AC input voltage and with a secondary winding;
an overvoltage protection means interconnected with each transformer primary winding and acting to limit the voltage applied to the primary winding to which it is connected;
a DC rectifier means connected to the transformer secondary and producing a first DC voltage on a first output connection when an AC voltage is applied to the primary windings of the transformer;
an overvoltage sensor connected to the first output connection and producing an overvoltage signal when the first DC voltage is higher than a predetermined level;
an undervoltage sensor connected to the first output connection and producing an undervoltage signal when the first DC voltage is lower than a predetermined level;
relay contact means interconnected with the two transformer primary windings in such a manner that the relay contact means can switch the two primary winding between a condition in which the primary windings are in series across the AC input voltage connection and a condition in which the two primary windings ar in parallel across the AC input voltage connection; and
relay coil means actuating the relay contact means and interconnected with and receiving signals from the overvoltage sensor and the undervoltage sensor, so that the relay contact means puts the transformer primary windings in parallel when the relay coil means receives an undervoltage signal, and the relay contact means puts the transformer primary windings in series when the relay coil means receives an overvoltage signal.
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Accused Products
Abstract
A power supply which automatically adapts to different input power sources. A double pole, double throw, latching relay switches the primaries of the rectifier transformer to a series or to a parallel configuration depending upon the output voltage of the rectifier, thus adapting the circuit to either a nominal 220 VAC source or a nominal 120 VAC source. The control circuit also derives power from the rectifier transformer and is designed to operate even under the worst possible undervoltage or overvoltage conditions. The additional choice of 24 VDC power is available by the use of a diode OR circuit. When a 24 VDC source is connected to the DC input, it is also connected to the rectifier output through a diode, so that power is furnished to the load by whichever source has the higher voltage. In this configuration, a battery pack can be connected to the DC input to supply automatic backup power.
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Citations
9 Claims
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1. An automatically switching DC power supply comprising:
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an AC input voltage connection; a transformer with two primary windings rated for the same AC input voltage and with a secondary winding; an overvoltage protection means interconnected with each transformer primary winding and acting to limit the voltage applied to the primary winding to which it is connected; a DC rectifier means connected to the transformer secondary and producing a first DC voltage on a first output connection when an AC voltage is applied to the primary windings of the transformer; an overvoltage sensor connected to the first output connection and producing an overvoltage signal when the first DC voltage is higher than a predetermined level; an undervoltage sensor connected to the first output connection and producing an undervoltage signal when the first DC voltage is lower than a predetermined level; relay contact means interconnected with the two transformer primary windings in such a manner that the relay contact means can switch the two primary winding between a condition in which the primary windings are in series across the AC input voltage connection and a condition in which the two primary windings ar in parallel across the AC input voltage connection; and relay coil means actuating the relay contact means and interconnected with and receiving signals from the overvoltage sensor and the undervoltage sensor, so that the relay contact means puts the transformer primary windings in parallel when the relay coil means receives an undervoltage signal, and the relay contact means puts the transformer primary windings in series when the relay coil means receives an overvoltage signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification