Power supply apparatus for field devices

• US 7,573,153 B2
• Filed: 12/14/2006
• Issued: 08/11/2009
• Est. Priority Date: 12/23/2005
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Rebbereh, Carsten
• Primary Examiner(s): Paladini; Albert W
• Assistant Examiner(s): CAVALLARI, DANIEL J
• Application Number:
  US11/610,773
• Publication Number:
  US 20080143190A1
• Time in Patent Office: 971 Days
• Field of Search: 307/38, 307/42, 307/115, 323/371, 439/638, 439/650
• US Class Current: 307/38
• CPC Class Codes: H02J 11/00 Circuit arrangements for providing service supply to auxiliaries of stations in which electric power is generated, distributed or converted
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence

Abstract

An apparatus for supplying DC power to a field device, such as a motor, starter or actuator, includes a multi-pole main switch and a DC voltage supply device, both of which are connected at their respective AC-voltage input sides to a line voltage via a line protection. The DC-voltage side of the DC voltage supply device is connected via a two-pole switch to respective lines of the same power cable that connects output terminals of the apparatus to the field device. The multi-pole main switch and the two-pole switch are ganged. This approach eliminates a separate DC power cable between the apparatus and the field device.

Claims

1. An apparatus for supplying DC power to input terminals of at least one field device operating on AC power via a single AC power cable, comprising:

a multi-pole main switch having an input side receiving an AC voltage from a power mains and an output side supplying a switched AC voltage to output terminals of the apparatus;

an AC power cable connecting the output terminals to the at least one field device;

a DC voltage supply device having an input side receiving the AC voltage from the power mains and a DC voltage output side;

a two-pole switch switchably connecting the DC voltage output side to two wires of the AC power cable, wherein the multi-pole main switch and the two-pole switch are ganged so as to supply only one of the switched AC voltage and the DC voltage to the at least one field device over the AC power cable.

2. The apparatus of claim 1, wherein each field device comprises a switched mode power supply which is buffered so as to bridge brief interruptions of AC power from the power mains.

3. The apparatus of claim 1, wherein the multi-pole main switch and the two-pole switch are ganged so that the multi-pole main switch and the two-pole switch are prevented from being closed at the same time.

4. The apparatus of claim 1, wherein the multi-pole main switch and the two-pole switch form a single unit.

5. The apparatus of claim 1, wherein the multi-pole main switch is a load-break switch.

6. The apparatus of claim 1, wherein the field device is a converter.

7. The apparatus of claim 1, wherein the field device is a motor starter.

8. The apparatus of claim 1, wherein the field device is an input/output module.

9. The apparatus of claim 1, further comprising a fuse disposed on the input side of the multi-pole switch or on the input side of the DC voltage supply device, or both, as line protection.