Programmable motor protector

• US 4,470,092 A
• Filed: 09/27/1982
• Issued: 09/04/1984
• Est. Priority Date: 09/27/1982
• Status: Expired due to Term

• Current Assignee: Allen-Bradley Company (Rockwell Automation, Inc.)
• Original Assignee: Allen-Bradley Company (Rockwell Automation, Inc.)
• Inventors: Lombardi, Steven A.
• Primary Examiner(s): Moose, Jr., Harry E.
• Assistant Examiner(s): Foster, Patrick W.
• Application Number:
  US06/423,793
• Time in Patent Office: 708 Days
• Field of Search: 364/483, 361/23, 361/25, 361/31
• US Class Current: 361/23
• CPC Class Codes: H02H 3/00 Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems H02H7/00; systems for change-over to standby supply H02J9/00 ; integrated protection for motors H02H7/0822
• CPC Class Codes: H02H 7/0822 Integrated protection, motor control centres

Abstract

A programmable motor protector includes a protect module which connects through one serial link to a programmer module and through a second serial link to an RTD module. The protect module is a microprocessor which is programmed to monitor the values of various motor operating parameters and compare them against alarm limits and trip limits which are entered through the programmer module. In addition to indicating a trip or alarm condition, the system saves in a diagnostic table an image of the motor operating conditions at the moment a trip is detected. This diagnostic table may be examined using the programmer module.

Claims

1. A programmable motor protector, the combination comprising:

means for storing an input image table;

means coupled to the motor for periodically reading the values of motor operating parameters and storing the values in the input image table storage means;

means for storing a diagnostic table;

means for storing a user entry table;

programmer means for entering values into the user entry table storage means which are indicative of trip levels for motor operating parameters;

trip means for indicating a trip condition when enabled;

comparator means coupled to the trip means and being operable to periodically compare values in the input image table storage means with corresponding trip level values in the user entry table storage means, and being operable to enble the trip means when a trip level is exceeded; and

transfer means coupled to the trip means for transferring values in the input image table storage means to the diagnostic table storage means when the trip means is enabled.

2. The programmable motor protector as recited in claim 1 in which the programmer means includes a display, and in response to the entry of a request, a value stored in the diagnostic table storage means is coupled to the display.

3. The programmable motor protector as recited in claim 2 which includes scan list storage means for storing a list of numbers which identify motor operating parameter values stored in the input image table storage means, and display means for sequentially reading motor operating parameter values indicated in the scan list storage means and coupling each value to the display.

4. A programmable motor protector, the combination comprising:

an RTD module which includes

(a) a first set of input circuits connected to resistance temperature detectors mounted in the motor to be protected;

(b) a first communication link for receiving command data and transmitting responsive RTD data;

(c) first processor means which is responsive to command data received by the first communication link for reading RTD data from a selected one of the input circuits and coupling this RTD data to the first communication link for transmission;

a protect module which includes;

(d) a second communication link coupled to the first communication link for transmitting command data and receiving responsive RTD data;

(e) A second set of input circuits coupled to sensors in the motor for sensing the value of motor operating parameters;

(f) input image table storage for storing RTD values and motor operating parameter values;

(g) user entry table storage for storing trip values corresponding to the RTD values and motor operating parameter values;

(h) second processor means coupled to the second communication link and the second set of input circuits, the second processor means being operable;

to periodically input motor operating parameter values from the second set of input circuits and store them in the input image table storage;

to periodically generate command data to the second communication link requesting RTD data from the first set of input circuits and storing the responsive RTD data received by the second communication link in the input image table storage; and

to periodically compare values in the input image table storage with corresponding trip values in the user entry table storage and to indicate a trip condition when one of the trip values is exceeded.

5. The programmable motor protector as recited in claim 4 in which the protect module includes a third communication link coupled to the second processor means and it includes a programmer module which communicates with the third communication link for entry of trip values, and the second processor is operable in response to trip value data received at the third communication link for storing the trip value data in the user entry table storage.

6. The programmable motor protector as recited in claim 5 in which the first, second and third communications links are serial communications links.