Apparatus and method for testing electrically controlled motor

• US 4,996,477 A
• Filed: 10/26/1989
• Issued: 02/26/1991
• Est. Priority Date: 10/26/1989
• Status: Expired due to Fees

• Current Assignee: A. O. Smith Corporation
• Original Assignee: A. O. Smith Corporation
• Inventors: Keeler, Randall W., King, James L.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Nguyen, Vinh P.
• Application Number:
  US07/427,795
• Time in Patent Office: 488 Days
• Field of Search: 324/158 R, 324/158 MG, 318/490, 318/690, 318/696, 340/648, 322/99
• US Class Current: 324/765.01
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines

Abstract

An on-site test unit is for an electric motor having an electronic timer having motor control contacts and a parallel capacitor completing a power connection with the opposite power connection being common. The test unit includes a portable housing with a fused power cable and an output connector. A switch, with a parallel test lamp, connects the power cable to connector output terminals. An internal test load lamp in parallel with a capacitor is connected in series to a control terminal and to a power terminal. A selection switch selectively supplies power to the terminals. For testing, the normal power supply is disconnected and the common connection to the motor and timer is opened. The connector may include a plurality of leads with terminal clips or releasable plug-in connectors in the motor and test unit. A dummy connector provides normal motor operation. In a motor test, the motor is connected by the selection switch to the power switch and cable. If the motor is inoperative and the power lamp lit, the motor needs repair. Momentary turn-on of the lamp indicates opening of the fused cable and a short-to-ground condition. In the timer position, power is connected to the timer and to the test lamp in series with the timer contacts, lights the test lamp if operative.

Claims

1. A portable test unit for a motor unit having an electric motor in combination with a separate controller said controller having a control output unit for controlling the power supply connection to said motor, said portable test unit having a separate test power supply and a selection switch unit having a first switch position connecting said test power supply to a motor test output unit and having a second switch position connecting said test power supply to a controller test output unit, and a connection unit for connecting of said motor test output unit to said motor and for connecting said controller test output unit to said controller to selectively and separately monitor and provide power from said test power supply to said motor in said first switch position and in said second switch position to said controller to selectively and separately monitor the state of said motor and said controller through the position of said selection switch unit, said test unit including a load unit connected to said connection unit and connecting a load in series circuit with said controller test output unit.

2. The portable test unit of claim 1, wherein said connection unit includes a first releasable connector unit in said motor, said first releasable connector unit having a first and second terminal connected to said motor winding and to said controller and having a third terminal connected to a common return line and a fourth terminal connected to the control output unit of said controller, said test unit includes a complementing releasable connector having first, second and third test terminals selectively connected to said test power supply and having a fourth terminals connected to the output unit of said controller, and said load unit connected between said fourth terminal and said third test terminal.

3. The portable test unit of claim 2, having a power switch connecting said test power supply to said selection switch unit for selectively connecting said test power supply to said complementing releasable connector, and a power indicator in parallel with said power switch.

4. The portable test unit of claim 3, wherein said selection switch unit is a double pole double throw switch unit having a first set of motor contacts and a second set of controller contacts and movable contacts selectively engaged with first and second sets of contacts, said movable contacts being connected to said power switch, said motor contacts being connected to said first and second test terminals, and said test contacts being connected to said third and fourth test terminals.

5. The portable test unit of claim 4, including a current responsive switch unit connected between the test power supply and said power switch, said current responsive switch unit opening in response to a short-to-ground current to said motor or said controller whereby said power indicator operates between the closing of the power switch and the opening of said current responsive switch unit.

6. The portable test unit of claim 1, wherein said controller includes a timer controlling a set of contacts forming said control output unit, said load unit includes a visual display establishing a visual indication of the timer operation.

7. The portable test unit of claim 6, having a switch connecting said test power supply to said selection switch unit for selectively connecting said test power supply to said complementing releasable connector, and a power indicator in parallel with said power switch, a current responsive switch unit connected between the test power supply and said power switch, said current responsive switch unit opening in response to a short-to-ground current to said motor or said controller whereby said power indicator operates between the closing of the power switch and the opening of said switch unit.

8. A motor test apparatus for monitoring an electronically controlled motor including an electronic control unit having a powered input for connecting to a power supply in parallel with the motor and having a control output unit connected to separately control the connection of the power supply to said motor and thereby control the operating state of said motor, said motor test apparatus comprising a separate power test supply adapted to supply power to said motor and to supply power to said electronic control unit for independent and separate operation thereof, a load unit adapted to be connected to said electronic control unit to simulate connection of said motor to said electronic control unit, test power connector means for selectively connecting of said separate test power supply to said motor to actuate said motor and to said electronic control unit to alternately actuate said electronic control unit, and a third connector means for connecting of said load unit in circuit with said control output unit of said electronic control unit to said power test supply.

9. The apparatus of claim 8, wherein said load unit includes a sensible output signal device for providing a sensible output signal to the user of the operating status of said electronic control unit.

10. The apparatus of claim 8, wherein said control output unit includes a switch means and a parallel transient current capacitor, and said load unit includes a lamp and a parallel transient current capacitor.

11. The motor test unit of claim 8, including a test power switch connected in said power test supply, a fuse unit connected in series with said power switch, a sensible indicator connected in parallel with said power switch and in series with said fuse unit.

12. The motor test unit of claim 8, wherein said third connector means includes a selection switch connected to said load unit and said power switch to supply power to one side of said load.

13. The motor test unit of claim 8, wherein said test power supply includes a power cable having first and second power leads and including a power connector plug for connection to a power distribution receptacle, a fuse unit, a power switch connected in series with said fuse unit to said power cable, first and second test leads connected to said power switch for supplying power to said motor or said control unit, a selection switch, a test lamp, a third test lead connected to one of said power leads in series with said test lamp and said selection switch, said test leads each including a manually releasable connector unit for selectively connecting said leads to said motor and to said control unit.

14. The motor test unit of claim 13, including a capacitor connected in parallel with said test lamp.

15. The apparatus of claim 8, including a sensible output unit connected in parallel with said test power supply and establishing a sensible output in response to conduction of power from said test power supply, and a current responsive switch unit connected to said power supply and said sensible output unit to operatively disconnect the power supply and thereby deactivate said sensible output unit in response to a short condition connected across said power supply by said motor or by said electronic control unit to thereby momentarily actuate said sensible unit and provide a short indicator.

16. The apparatus of claim 15, wherein said current responsive switch unit includes a fuse.

17. The apparatus of claim 8, including a releasable plug assembly including a first plug member mounted to said motor and connected to said motor and said electronic control unit and to the incoming power supply, said first plug member including first and second circuit connectors connected to said motor and said electronic control for supply power thereto, said plug member having a third circuit connector connected to said control output unit of said electronic control unit and to said motor and a fourth circuit connector connected to a common return line connected to said control output unit, said motor test apparatus including a complementary plug member having connectors complementing said first plug member, said complementing plug member having first and second power connectors aligned with said first and second circuit connectors, said complementing plug member having a third releasable connector aligned with said third circuit connector and a fourth releasable connector aligned with said fourth circuit connector, and said load unit being connected between said second releasable connector and said third releasable connector.

18. The apparatus of claim 17, including a power cable including a fuse responsive to abnormal current flow, a power switch connected to said cable and including a lamp indicator connected in parallel with the test side of said power switch, a selection switch unit including contacts connected to said power switch and movable into engagement with test timer contacts and alternately with test motor contacts, said test motor contacts being connected to the first releasable connector of said releasable plug member and to the fourth releasable connector, said test timer contacts being connected to said second and third releasable connectors, and a load unit including a sensible output unit connected between the second and the fourth releasable connectors and thereby establishing a circuit from the test power cable through said load circuit in series with said control output unit to monitor the operating status of said control unit and said output unit.

19. The apparatus of claim 17, including a test power cable, a fuse connected to said power cable, a power switch connected to said fuse and cable, said power switch connected to said releasable plug member, a sensible indicator connected to the output side of said switch for providing a sensible output upon closure of said power switch, a short-to-ground condition in the motor or control unit under test creating an abnormal current flow through the test cable fuse and thereby opening the power circuit to the power switch and de-energizing of said lamp, the energization and de-energization of said lamp providing a sensible output indicating the short-to-ground condition.

20. A motor fault unit for testing a motor having a controller selectively connecting said motor winding to an incoming power supply, said controller having an electrical operator for a controller connecting means between said motor winding and said power supply, comprising a separate power supply unit having a first line and a second line, a power switch unit having a first switch in said first line and a second switch in said second line, a power switch indicator energized with said switch closed, a control state indicator connected to said first line downstream of said power switch, a test connector including a first power connector and a second power connector and a control test connector connected to said control state indicator, and said test connector having first connection means connecting said first and second lines directly to said motor winding for operating said motor from said separate power supply unit, and said test connector having a second connection means connecting said first and second lines directly to said controller for energizing said operator and connecting said control state indicator in circuit with the first connecting means across said first and second lines for monitoring the state of said controller.

21. The motor fault test unit of claim 20, including a replaceable fuse unit in said power supply unit upstream of said power switch unit, and said power switch unit indicator has a visual output whereby said indicator is momentarily actuated in the presence of a short condition in said motor or in said controller.

22. The motor fault test unit of claim 20, wherein said control state indicator includes a lamp in parallel with a capacitor, said capacitor being operable to pass the transient signals of said controller.

23. The motor fault detector of claim 20, wherein first and second power connectors include a releasable connector unit for temporary connection to said motor and to said controller and operable to directly operate said motor and said operator of said controller, and including an operator connector including a releasable connector unit for connecting said control state indicator in a series circuit with said controller connecting means and with said series circuit in parallel with said operator.

24. A motor and a motor control unit test method for a motor and a control unit for controlling operation of said motor and having first power connection connected to said motor and to said control unit and a second power connection to said control unit and said control unit having a control output connecting the motor to said second power connection comprising establishing a separate test power supply unit for establishing an operating voltage for operating the motor and for operating the said control unit, opening the first power connection between the motor and said control unit to provide separate power connections to the motor and to the control unit, connecting said test power supply directly to said motor for direct testing the state of said motor, disconnecting the test power supply from said motor, connecting said test power supply to said separate power connection to said control unit and to said second connections to actuate said control unit, and connecting a load unit between said control output and said separate power connection to said control unit to simulate a motor load for testing said control unit.

25. The test method of claim 24, wherein said control output includes a contact connecting the motor to said second power connection, and said load unit is connected to said switch unit in common with said motor.

26. The test method of claim 25, wherein said control output includes a transient signal capacitor connected in parallel with said contact, and including forming said load with an inductive winding and a transient signal capacitor in parallel with said inductive winding.