SUPERVISORY APPARATUS

• US 3,651,402 A
• Filed: 01/27/1969
• Issued: 03/21/1972
• Est. Priority Date: 01/27/1969
• Status: Expired due to Term

• Current Assignee: Paul H. Leffmann
• Original Assignee: Paul H. Leffmann
• Inventors: Leffmann, Paul H.
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): Karlsen, Ernest F.
• Application Number:
  US04/797,355
• Time in Patent Office: 1,149 Days
• Field of Search: 324/158,83,158SM,158MG,83A,177 318/490,175,178,179 310/162,163
• US Class Current: 324/765.01
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines
• CPC Class Codes: H02K 19/08 Motors having windings on the stator and a smooth rotor without windings of material with large hysteresis, e.g. hysteresis motors
• CPC Class Codes: Y10S 174/14 having a particular cable application, e.g. winding
• CPC Class Codes: Y10S 174/16 in a motive power system, e.g. electric motor control system

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.

Claims

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.

2. The method of claim 1 in which said characteristic comprises a sudden rapid shift of 5* as synchronous speed is achieved.

3. The method of claim 1 in which said characteristic comprises a small oscillation when synchronous speed is achieved.

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.

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.