Starter contact integrity test
AssigneeAmerican Standard Inc.
InventorMichael W. Murry
Life of this patent
Estimating the term…
Abstract
An apparatus for detecting faults in a starter circuit adapted to connect a multi-phase electrical motor to a power supply. The motor has at least one winding per phase, each of which terminates in at least one terminal. The starter circuit includes a plurality of contactors which are energizable to connect the motor windings to the power source. The fault detection apparatus comprises a current sensor for sensing the current flowing through the windings of each phase and responsively producing respective winding current signals. A diagnostic module controllably energizes the contactors, samples for the presence and absence of the winding current signals while different ones of the contactors are energized to detect faults in the contactors, and responsively produces fault signals.
Claims30
An apparatus for detecting faults in a starter circuit adapted to connect a multi-phase motor to a power supply, the motor having at least one terminal per phase, the starter circuit including a plurality of contactors which are energizable to connect the motor terminals to the power source, the apparatus comprising:
- current sensing means for sensing the current flowing through each phase and responsively producing respective phase current signals;
- and
- diagnostic means for controllably energizing the contactors, sampling for the presence and absence of the winding current signals while different ones of the contactors are energized to detect faults in the contactors, and responsively producing fault signals.
An apparatus for detecting faults in a wye-delta starter circuit adapted to connect a three-phase motor to a three phase power supply, the motor having at least a first terminal and a second terminal per phase, the starter circuit including at least one shorting contactor adapted to receive a shorting signal and responsively close shorting contacts to connect the winding second terminals together, at least one starting contactor adapted to receive a start signal and close start contacts to connect each of the winding first terminals to a different power supply phase, and at least one run contactor adapted to receive a run signal and responsively close run contacts to connect each of the winding second terminals to a different one of the power supply phases, such that when the contacts of the run and shorting contactors are closed the motor is energized in a wye configuration and when the start and run contacts are closed the motor is energized in a delta configuration, the apparatus comprising;
- current sensing means for sensing the current flowing through each phase and responsively producing respective phase current signals;
- and
- diagnostic means for controllably producing the short, start, and run signals, sampling for the presence and absence of the phase current signals while different combinations of the short, start and run signals are produced to detect faults in the contactors, and responsively producing fault signals.
A method for detecting faults in a starter circuit adapted to connect a multi-phase motor to a power supply, the motor having at least one terminal per phase, the starter circuit including a plurality of contactors which are energizable to connect the motor terminals to the power source, the method comprising the steps of:
- controllably energizing the contactors;
- sampling for the presence and absence of the terminal current signals while different ones of the contactors are energized to detect faults in the contactors;
- producing fault signals in response to detected faults;
- and
- providing a visual indication of the nature of any detected faults in response to the fault signals.
A method for detecting faults in a wye-delta starter circuit adapted to connect a three-phase motor to a three phase power supply, the motor having at least a first terminal and a second terminal per phase, the starter circuit including at least one shorting contactor adapted receive a shorting signal and responsively close shorting contacts to connect the second terminals together, at least one starting contactor adapted to receive a start signal and close start contacts to connect each of the first terminals to a different power supply phase, and at least one run contactor adapted to receive a run signal and responsively close run contacts to connect each of the second terminals to a different one of the power supply phases, such that when the contacts of the shorting and start contactors are closed the motor is energized in a wye configuration and when the start and run contacts are closed the motor is energized in a delta configuration, the method comprising the sets of:
- controllably producing the short, start, and run signals in preselected combinations;
- sampling for the presence and absence of current flow through the motor terminals while the preselected signal combinations are produced to detect failed conditions in the contactors;
- and
- producing fault signals that indicate the nature of the detected failed conditions in the contactors.
A method of verifying starter contact integrity while starting a wye delta starter which includes start contactors, run contactors, short contactors, transition contactors and auxiliary run contactors, the method comprising the steps of:
- opening all start, run, transition, auxiliary run, and shorting contacts;
- verifying that the auxiliary run contacts have closed;
- closing the start contactor;
- verifying current flow;
- opening the start contactors;
- closing the short contactors;
- verifying current flow;
- opening the start contractors;
- verifying current flow;
- closing the transition contacts;
- opening the shorting contacts;
- energizing the run contacts;
- and
- opening the transition contacts.
Dependencies are inferred from the claim text.