Dynamoelectric machine with improved winding protection arrangement

Claim 1

IN A THERMALLY PROTECTED, SINGLE PHASE ALTERNATINGCURRENT INDUCTION ELECTRIC MOTOR ADAPTED TO OPERATE SELECTIVELY AT FIRST AND SECOND VOLTAGES, SINGLE PHASE STATOR HAVING ONE CIRCUIT MEANS ADAPTED FOR ENERGIZATION INCLUDING AT LEAST TWO WINDING SECTIONS EACH IN SERIES CIRCUIT WITH A FIRST HEAT SENSING CIRCUIT-INTERRUPTING DEVICE AND IN PRIMARY HEAT TRANSFER RELATION THEREWITH, SAID FIRST HEAT SENSING DEVICE BEING PRIMARILY RESPONSIVE TO A PREDETERMINED HEAT CONDITION OF THE AT LEAST TWO WINDING SECTIONS; AN OTHER CIRCUIT MEANS ADAPTED FOR ENERGIZATION INCLUDING AT LEAST TWO OTHER WINDING SECTIONS EACH IN SERIES CIRCUIT WITH A SECOND HEAT SENSING CIRCUIT-INTERRUPTING DEVICE AND IN PRIMARY HEAT TRANSFER RELATION THEREWITH, SAID SECOND HEAT TRANSFER CIRCUIT-INTERRUPTING DEVICE BEING PRIMARILY RESPONSIVE TO A PREDETERMINED HEATED CONDITION OF THE AT LEAST TWO OTHER WINDING SECTIONS AND GENERALLY INSENSITIVE TO THE PREDETERMINED HEATED CONDITION OF THE AT LEAST TWO WINDING SECTIONS OF SAID OTHER CIRCUIT MEANS, SAID ONE CIRCUIT MEANS AND SAID OTHER CIRCUIT MEANS BEING CONNECTED IN SERIES RELATION FOR A SECOND VOLTAGE OPERATION, AND IN PARALLEL RELATION FOR A SECOND VOLTAGE OPERATION, SAID FIRST AND SECOND HEAT SENSING CIRCUIT-INTERRUPTING DEVICES BEING INDEPENDENTLY OPERATIVE TO DEENERGIZE ALL OF THE WINDING SECTIONS IN BOTH SAID ONE AND SAID OTHER CIRCUIT MEANS WHEN THE PREDETERMINED HEAT CONDITION IS REACHED IN EITHER OF THE ASSOCIATED AT LEAST TWO WINDING SECTIONS DURING SAID FIRST VOLTAGE OPERATION TO INTERRUPT OPERA TION OF THE MOTOR; AND ONE OF THE HEAT SENSING CIRCUITINTERRUPTING DEVICES BEING OPERATIVE FOR DEENERGIZING ONLY ITS ASSOCIATED AT LEAST TWO WINDING SECTIONS WHEN THE PREDETERMINED HEATED CONDITION IS REACHED IN THE VICINITY OF SUCH WINDING SECTIONS THEREBY CHANGING THE ELECTRICAL IMPEDANCE OF THE STATOR WITHOUT INTERRUPTING OPERATION OF THE MOTOR DURING SAID SECOND VOLTAGE OPERATION, WHEREBY THE MOTOR MAY BE OPERATED AT LEAST TEMPORARILY AT THE SECOND VOLTAGE WITH THE REMAINING WINDING SECTIONS STILL BEING ENERGIZED UNTIL THE PREDETERMINED HEATED CONDITION IS REACHED IN THE VICINITY OF THE OTHER HEAT SENSING CIRCUITINTERRUPTING DEVICE TO OPERATE THAT DEVICE FOR DEENERGIZING ITS ASSOCIATED AT LEAST TWO WINDING SECTIONS TO INTERRUPT OPERATION OF THE MOTOR.