Polyphase emulator for single phase circuit

• US 5,297,016 A
• Filed: 05/27/1993
• Issued: 03/22/1994
• Est. Priority Date: 05/27/1993
• Status: Expired due to Term

• Current Assignee: Itron, Inc.
• Original Assignee: Schlumberger Industries Incorporated (SLB)
• Inventors: Stephens, George H., Goodwin, R. Wendell
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): NGUYEN, MATTHEW VAN
• Application Number:
  US08/068,490
• Time in Patent Office: 299 Days
• Field of Search: 363/148, 363/149, 363/156, 331/45, 328/24, 315/138, 315/140
• US Class Current: 363/149
• CPC Class Codes: G01R 35/04 of instruments for measuring time integral of power or current
• CPC Class Codes: H02M 5/14 for conversion between circuits of different phase number

Abstract

An emulator which is able to operate on a standard single phase 120 VAC line, generates simulated three-phase alternating current in order to demonstrate the operation of a polyphase electricity meter. The emulator is also capable of demonstrating the operation of the polyphase electricity meter which has been incorrectly wired into the polyphase circuit, i.e., with incorrect or missing connections to the current transformers; or in which there are problems with the phasing of the polyphase circuit, i.e., incorrect phase differences between circuits or between the currents and voltages within any of the phases.

Claims

1. A polyphase emulator for use in demonstrating the functionality of a polyphase electricity meter and for operation on a single phase electricity circuit comprising:

a. phase generating circuit means for generating multiple sets of currents and voltages, each of said sets having a nominal predetermined phase relationship with respect to each of the other sets, said phase generating circuit means including means for altering said nominal predetermined phase relationships between said sets of currents and voltages; and

b. a plurality of phase specific circuit means, the number of said phase specific circuit means corresponding to the number of sets of currents and voltages generated by said phase generating circuit means, each of said plurality of phase specific circuit means including means for emulating specific parameters which relate to the phase relationships between the voltage and current within each of said sets as they relate to each other and to the voltage and currents within other ones of said sets.

2. The polyphase emulator of claim 1 wherein said phase generating circuit means produces three sets of currents and voltages.

3. The polyphase emulator of claim 2 wherein the second of said three sets of currents and voltages is nominally 120 degrees out of phase with respect to the first of said three sets of currents and voltages, and the third of said three sets of currents and voltages is nominally 240 degrees out of phase from the first of said three sets of currents and voltages.

4. The polyphase emulator of claim 3 wherein there are three phase specific circuit means corresponding to the number of sets of currents and voltages generated by said phase generating circuit means, each of said plurality of phase specific circuit means including means for emulating specific parameters relating to the voltage and current within each of said sets.