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US 3,942,111 AGranted
Method and apparatus for testing electric motors
AssigneeWhirlpool Corporation
InventorJohn Richard Pfouts
Life of this patent
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AssigneeWhirlpool Corporation
InventorJohn Richard Pfouts
Estimating the term…
To determine whether a motor is operative, where visual inspection of rotation is impossible or difficult, the motor is energized by connection to an AC source for a short interval to bring the motor to running speed. After lapse of the short interval, the AC source is disconnected and the motor coasts to a stop. An AC detector determines that AC power has been terminated and closes a switch to connect a voltage detector to a memory. The voltage detector amplifies an EMF generated while the motor is acting as a generator as the motor coasts to a stop. The detected voltage sets the memory which energizes a motor rotation indicator. For improved accuracy in the determination of the operativeness of the motor, the motor is caused to be tested a plurality of times as the result of a single operation of a control member by the test operator. To further facilitate the testing operation, the control is arranged to provide a signal to the testing operator effectively positively indicating the operativeness of the motor while yet permitting the operator to have his visual attention elsewhere. A time delay is provided in the provision of the indication signals effectively preventing spurious indications.
A method of testing an electric motor having a residual magnetic field such that upon de-energization of the running motor an EMF is produced in the windings of the motor, said method comprising the steps of:
A method of testing an electric motor having a residual magnetic field such that upon de-energization of the running motor an EMF is produced in the windings of the motor, said method comprising the steps of:
An apparatus for testing an electric motor having a residual magnetic field such that upon de-energization of the running motor an EMF is produced in the windings of the motor, said apparatus comprising:
An apparatus for testing an electric motor having a residual magnetic field such that upon de-energization of the running motor an EMF is produced in the windings of the motor, said apparatus comprising:
Dependencies are inferred from the claim text.