SUPERVISORY APPARATUS
First Claim
1. The method of testing a hysteresis synchronous motor having a rotor and a pair of stator windings the first of which is energized directly from an alternating voltage source and the second of which is energized from the source through a capacitor, which comprises the steps of energizing the motor, monitoring the phase angle relation between the alternating voltage across said second winding and a reference alternating voltage of preset fixed phase, and confirming the presence in said relation of a characteristic representative of satisfactory motors.
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Abstract
1. The method of testing a hysteresis synchronous motor having a rotor and a pair of stator windings the first of which is energized directly from an alternating voltage source and the second of which is energized from the source through a capacitor, which comprises the steps of energizing the motor, monitoring the phase angle relation between the alternating voltage across said second winding and a reference alternating voltage of preset fixed phase, and confirming the presence in said relation of a characteristic representative of satisfactory motors.
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Citations
5 Claims
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1. The method of testing a hysteresis synchronous motor having a rotor and a pair of stator windings the first of which is energized directly from an alternating voltage source and the second of which is energized from the source through a capacitor, which comprises the steps of energizing the motor, monitoring the phase angle relation between the alternating voltage across said second winding and a reference alternating voltage of preset fixed phase, and confirming the presence in said relation of a characteristic representative of satisfactory motors.
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2. The method of claim 1 in which said characteristic comprises a sudden rapid shift of 5* as synchronous speed is achieved.
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3. The method of claim 1 in which said characteristic comprises a small oscillation when synchronous speed is achieved.
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4. The method of claim 1 with the further preliminary steps of first operating the motor at synchronous speed, then setting the phase angle of the reference voltage, with respect to the signal voltage, at a predetermined value, then deenergizing the motor to bring it to rest.
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5. In combination:
- a hysteresis synchronous motor having a first winding energized directly from a source of alternating voltage and a second winding reactively energized from said source, the phase of the voltage across said second winding varying as the motor varies in speed;
means connected to said motor for deriving, from the voltage across said second winding, pulses of undirectional current synchronized with one of the peaks thereof;
gating means adjustably synchronized with the voltage across said first winding for deriving from said pulses a unidirectional signal which is of a first sense when the motor is running at less than synchronous speed, and which reverses in sense as the motor reaches synchronous speed; and
indicating means energized with said unidirectional signal so that the indication thereof varies with variation in the speed of said motor.
- a hysteresis synchronous motor having a first winding energized directly from a source of alternating voltage and a second winding reactively energized from said source, the phase of the voltage across said second winding varying as the motor varies in speed;
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