Brushless servo motor tester

• US 7,462,999 B2
• Filed: 03/29/2006
• Issued: 12/09/2008
• Est. Priority Date: 03/29/2006
• Status: Expired due to Fees

• Current Assignee: Mitchell Electronics, Inc.
• Original Assignee: Mitchell Electronics, Inc.
• Inventors: Mitchell, Stuart Glen, Mitchell, Lawrence Hardy
• Primary Examiner(s): Ro; Bentsu
• Application Number:
  US11/391,832
• Publication Number:
  US 20070229018A1
• Time in Patent Office: 986 Days
• Field of Search: 318/138, 318/254, 318/439, 318/490, 318720-724, 318/400.01, 318/400.04, 318/400.37, 318/400.38, 318/700, 324177-178, 324/772, 324/179, 324/117.H, 324/527, 731/16
• US Class Current: 318/490
• CPC Class Codes: G01R 31/343 in operation

Abstract

A permanent magnet brushless (PMBL) servo motor test apparatus and method allow testing of a motor in place. A set of static and dynamic tests is performed to determine proper motor operation of armature windings and rotor feedback devices. The test system of the present invention displaces the motor drive system. The test system comprises an armature driver, a feedback device input, and a system controller. The armature windings of the motor-under-test are driven in a polarity sequence according to a test sequence, whereby the rotor is driven in a series of rotations. Angle feedback is tested at a plurality of said rotations. Rotor velocity outputs are tested during said rotations. Armature current and voltage are determined at a plurality of said rotations and winding balance is tested. Said power switch is also operative to apply a voltage between the armature windings and the motor case to test for fault current flow.

In another embodiment of the invention, motor identification is decoded by the system into motor configuration and motor operation parameters, necessary to test the motor. Motor identification may be entered by an operator or captured from machine readable tags such as a barcode tag or an RFID tag.

Claims

1. An apparatus for testing a permanent magnet brushless servo motor, the motor comprising plural phase armature windings, a rotor, and a rotor state feedback device, said apparatus comprising:

a) an armature driver connected to the motor armature windings, said armature driver operative to power the armature in a polarity sequence, whereby the rotor is driven in a series of rotations;

b) a feedback input for receiving rotor state, said feedback input configurable for multiple motor configurations; and

c) a test controller connected to said feedback input, said test controller operative to perform rotor state feedback device tests.

2. The apparatus of claim 1 wherein said polarity sequence drives all armature windings simultaneously.

3. The apparatus of claim 1 wherein said test controller is connected to said armature driver, and said test controller is operative to control rotor movement.

4. The apparatus of claim 3 wherein said apparatus additionally comprises a monitor to measure at least one armature operating parameter, said test controller connected to said monitor, said test controller operative to perform an armature test based on said operating parameter.

5. A method for testing a permanent magnet brushless servo motor, the motor comprising plural phase armature windings, a rotor, and a rotor state feedback device, said method comprising the steps of:

a) applying DC power to the armature windings in a polarity sequence, wherein all armature windings are simultaneously driven, whereby the rotor is driven in a series of rotations; and

b) monitoring the feedback device output for expected operation at a plurality of said rotations.

6. The method of claim 5 additionally comprising the step of determining armature winding balance from armature voltages and currents determined at a plurality of said rotations.

7. The method of claim 6 wherein said armature winding balance comprises the ratios of each winding resistance to the mean winding resistance.

8. The method of claim 7 additionally comprising the step of comparing said ratios to a threshold.

9. An apparatus for testing a permanent magnet brushless servo motor, the motor comprising plural phase armature windings, a rotor, a rotor state feedback device, and a brake with a brake release, said apparatus comprising:

a) an armature driver connected to the armature windings, said armature driver operative to power the armature in a polarity sequence, whereby the rotor is driven in a series of rotations;

b) a feedback input for receiving rotor state;

c) a brake release driver for driving the brake release; and

d) a test controller connected to said feedback input, connected to said armature driver, and connected to said brake release driver, said test controller operative to release the brake, control the rotor movement, perform rotor state feedback device tests, and perform armature tests.

10. An apparatus for testing a permanent magnet brushless servo motor, said apparatus comprising:

a) an input for receiving motor identification;

b) a decoder, connected to said input, for decoding the motor identification to obtain motor configuration and operating parameters; and

c) a test system, connected to said decoder, and connected to the motor, for testing the motor according to said motor configuration and operating parameters.

11. The apparatus of claim 10 wherein said motor identification comprises a part number that includes die motor configuration and operating parameters.

12. The apparatus of claim 10 wherein said motor identification doesn'"'"'t include motor configuration and operating parameters, said decoder operative to retrieve motor configuration and operating parameters from a database, for motors to be tested.

13. A method for testing a permanent magnet brushless servo motor, said method comprising:

a) inputting motor identification;

b) decoding motor operating parameters from said motor identification; and

c) performing a feedback device test on the motor.

14. The method of claim 13 additionally comprising the step of performing an armature test.