Motor control apparatus with parallel input, serial output signal conditioning means

• US 4,434,390 A
• Filed: 01/15/1982
• Issued: 02/28/1984
• Est. Priority Date: 01/15/1982
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Elms, Robert T.
• Primary Examiner(s): Smith, Jr., David
• Application Number:
  US06/339,603
• Time in Patent Office: 774 Days
• Field of Search: 318/798, 318/806, 318/471, 318/472, 318/473, 361/24, 361/27
• US Class Current: 318/473
• CPC Class Codes: H01H 2071/006 Provisions for user interfaces for electrical protection devices
• CPC Class Codes: H02H 3/083 for three-phase systems
• CPC Class Codes: H02H 3/085 making use of a thermal sensor, e.g. thermistor, heated by the excess current also responsive to the temperature of the protected device H02H5/041, thermal images H02H6/00
• CPC Class Codes: H02H 7/0822 Integrated protection, motor control centres
• CPC Class Codes: H02P 1/02 Details
• CPC Class Codes: H02P 1/26 for starting an individual polyphase induction motor
• CPC Class Codes: H02P 23/0077 Characterised by the use of a particular software algorithm

Abstract

A motor starter, which may be microprocessor-controlled, is taught wherein a signal conditioning means is provided for receiving from the motor windings parallel inputs and motor bearings which are related to the motor winding and bearing temperatures and for operating on these parallel input signals in such a manner as to provide a single serial output signal for use by a control means to cause the motor control starting sequence or the normal motor run condition to be interrupted, for example, if any one of the temperatures is above a predetermined level.

Claims

1. A motor controller, comprising:

(a) digital control means electrically interconnected with a source of motor power and with an electric motor for conducting said power to said motor and for interrupting said power in response to a predetermined condition;

(b) a plurality of resistance temperature detector means for providing a multiplicity of analog signals one of which is indicative of the existence of said predetermined condition;

(c) a plurality of signal conditioning means each of which is interconnected with one of said resistance temperature detector means for converting the resistance value of said resistance temperature detector means to an analog voltage signal which is temperature related;

(d) first multiplex means interconnected at the input thereof in parallel with each of said signal conditioning means for converting said parallel analog voltage signal to serial analog voltage signals;

(e) analog to digital conversion means interconnected at the input thereof with said first multiplexer means for receiving said serial analog voltage signals and for providing at the output thereof parallel digital signals representative of said input analog voltage signals; and

(f) second multiplexer means interconnected with said analog to digital conversion means for converting said parallel digital signals to a serial train of signals, said digital train of signals being provided to said digital control means for providing a digital indication of said predetermined condition to said digital control means.

2. The combination as claimed in claim 1 wherein said predetermined condition is related to motor winding temperature.

3. The combination as claimed in claim 1 wherein said predetermined condition which is related to motor bearing temperature.

4. The combination as claimed in claim 1 wherein said digital control means and said second multiplexer means are optically isolated from each other.

5. The combination as claimed in claim 4 wherein said motor is stopped as a function of the flow of larger than normal current in a portion of said motor.

6. The combination as claimed in claim 5 wherein said current is fault current.