Westinghouse Electric Corporation

George T Mallick

Robert C Miller

Peter R Emtage

A method is provided for testing induction motors, particularly single-phase fractional horsepower motors, which enables routine testing of all motors in production for both starting and running torque and other desired characteristics. The method consists essentially of applying power to the motor for a very short period of time, such as three or four cycles of the supply voltage, then interrupting the power supply and immediately measuring the instantaneous speed by observing the induced voltage from the deenergized motor terminals. The torque then is verified from the change in speed over this short period. Both starting and running torques can be tested very quickly in this manner by means of solid-state control and computing devices, without connecting anything to the motor other than the power leads. Other desired characteristics of the motor can also be readily determined.

Method of testing induction motors

An automatic punch press and monitoring system. The monitoring system includes a piezoelectric accelerometer mounted within the stationary die shoe of the punch press, and electronic circuitry including a variable gain amplifier, a detector, an integrator, and a comparator. The monitoring system is manually placed in a 'LEARN' mode whereupon the signal produced by the accelerometer during normal operation of the punch press is amplified, detected, and integrated over the time period of one stroke to produce a test function. The gain of the amplifier is automatically adjusted during successive normal strokes of the punch press until the test function is equal to an arbitrary set point, thereby establishing a reference function. The monitoring system is then automatically placed in an 'AUTO CONTROL' mode whereupon on each succeeding stroke, with the gain of the amplifier fixed, the test function produced is compared with the reference function. If the test function is above a first high limit level corresponding to a percentage of the reference function and below a second high limit level corresponding to a second percentage of the reference function a check alarm is activated. If the test function is above the second high limit level or below a low limit level corresponding to a third percentage of the reference function the punch press is shut down.

Method for controlling an automatic machine tool

Automatic machine tool including a monitoring system

A circuit breaker including a flux transfer trip mechanism and a solid state passive overcurrent sensing device having a temperature-dependent switching resistor of resistance material such as vanadium dioxide or lanthanum cobalt oxide.

Circuit breaker with solid state passive overcurrent sensing device

The invention relates to a trapezoidal, ladder-type coil configuration positioned as an inverted U to provide a passage thereunder for use in conjunction with magnetic field generating and magnetic field measuring circuitry to detect the presence of metal devices associated with objects, i.e., parcels or persons, passing through the passage. The ladder configuration of the coil establishes magnetic fields within the passage which exhibit sufficiently strong components in three orthogonal directions (x, y and z) to assure detection of metal devices regardless of the orientation of the metal devices.

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Pittsburgh, PA, United States of America

George T Mallick