Power supply apparatus

• US 5,247,205 A
• Filed: 07/25/1991
• Issued: 09/21/1993
• Est. Priority Date: 07/26/1990
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Mototani, Shuuji, Nakamura, Mitsuo
• Primary Examiner(s): GAFFIN, JEFFREY A
• Application Number:
  US07/736,042
• Time in Patent Office: 789 Days
• Field of Search: 307/11, 307/18, 307/19, 307/23, 307/43, 307/64, 307/66
• US Class Current: 307/66
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence
• CPC Class Codes: H02J 9/061 for DC powered loads

Abstract

A power supply apparatus for supplying a direct current to a load includes a circuit breaker, and an AC/DC converter for converting an alternating current passed through the circuit breaker into a direct current. The direct current is supplied to the load. A battery supplies a direct current to the load when the AC/DC converter is in an abnormal state, and a switch is connected between the output of the AC/DC converter and the battery and between the load and the battery. Switch drive units control the switch in such a way that, when the circuit breaker is in an on state, the switch is turned on to connect the battery to the AC/DC converter and to the load. When the circuit breaker is in an off state, the switch is turned off to disconnect the battery from the load, whereby an unnecessary battery back up operation is prevented.

Claims

1. A power supply apparatus for supplying a direct current to a load, comprising:

a circuit breaker;

an AC/DC converter, connected to said circuit breaker and to said load, for converting an alternating current passed through said circuit breaker to a direct current, said direct current being supplied to said load;

a battery for supplying a direct current to said load when said AC/DC converter is in an abnormal state;

a switch connected between the output of said AC/DC converter and said battery and between said load and said battery; and

switch drive means, operatively connected to said circuit breaker, for driving said switch in such a way that when said circuit breaker is on, said switch is turned on to connect said battery to said AC/DC converter and to said load, and when said circuit breaker is off, said switch is turned off to disconnect said battery from said load;

said switch drive means including an auxiliary contact and a relay connected in series between one polarity output and another polarity output of said AC/DC converter, said auxiliary contact being closed when said circuit breaker is in an on state and said auxiliary contact being opened when said circuit breaker is in an off state, said relay turning on said switch when said auxiliary contact is closed, and said relay turning off said switch when said auxiliary contact is opened.

2. A power supply apparatus as claimed in claim 1 wherein said auxiliary contact is included in said circuit breaker.

3. A power supply apparatus for supplying a direct current to a load, comprising:

a circuit breaker;

an AC/DC converter, connected to said circuit breaker and to said load, for converting an alternating current passed through said circuit breaker to a direct current, said direct current being supplied to said load;

a battery for supplying a direct current to said load when said AC/DC converter is in an abnormal state;

a switch connected between the output of said AC/DC converter and said battery and between said load and said battery;

switch drive means, operatively connected to said circuit breaker, for driving said switch in such a way that when said circuit breaker is on, said switch is turned on to connect said battery to said AC/DC converter and to said load, and when said circuit breaker is off, said switch is turned off to disconnect said battery from said load; and

an over current detecting means, operatively connected to said circuit breaker and to said switch drive means, for detecting an over current flowing through said circuit breaker,

said switch drive means turning on said switch in response to the detection of an over current by said over current detecting means.

4. A power supply apparatus as claimed in claim 3, wherein said over current detecting means comprises a short detecting contact and a relay connected in series between one polarity and another polarity of the outputs of said AC/DC converter, said short detecting contact being closed when said circuit breaker is turned off due to an over current flowing through said circuit breaker, to thereby energize said relay so that said switch is turned on.

5. A power supply apparatus as claimed in claim 4, wherein said battery and said switch are connected in series between one polarity output and another polarity output of said AC/DC converter.

6. A power supply apparatus as claimed in claim 5, wherein said switch drive means comprises an auxiliary contact and said relay connected in series between one polarity output and another polarity output of said AC/DC converter, said auxiliary contact being closed when said circuit breaker is in an on state and said auxiliary contact being opened when said circuit breaker is in an off state, said relay turning on said switch when said auxiliary contact is closed, and said relay turning off said switch when said auxiliary contact is opened.