US2088478A - Split-cycle timing device - Google Patents

Description

y 27, 1937- J. F. KOVALSKY 2,088,478

SPLIT-CYCLE TIMING DEVICE Filed Oct. 27, 1954 Current I v V l l .4 .6 l I a w 2 4 6 .a a0 a .4 .6 .a

INVENTOR AT EY Wine in Cycles.

Patented July 27, 1937 UNITED STATES PATENT OFFICE SPLIT -CYCLE TIMING DEVICE of Pennsylvania Application October 27, 1934, Serial No. 750,304

Claims.

- My invention relates to electric discharge apparatus, and, in one aspect, to such apparatus for measuring time intervals of the order of 1/60 of a second within accuracy limits of the order of 5 1/1200 of a second. For such purposes, my invention is particularly applicable to the measurement of the time of response of high-speed electrical apparatus, such as regulator elements, protective relays and circuit breakers.

In its more general aspects, my invention embraces novel methods and apparatus for electrically storing a. measured indication and afterward utilizing such stored indication for electrical controlor other purposes. In connection with the application of my invention for the measurement of time intervals, recent development in high-speed regulators and in protective apparatus for transmission circuits have led to the introduction of relay elements which operate in a time interval of the order of 1 or 2 cycles of a 60 cycle supply, and of contactors which operate in a time interval of the order of 2 cycles. The performance of such apparatus may be satisfactorily recorded by means of an oscillograph, but the cost of films and of the oscillograph itself, as well as the time and care necessary to obtain comparative results render the use of this instrument objectionable for such purposes.

It is an object of my invention to provide a simple direct-reading instrument which will give a numerical indication of the time values sought,

Fig. 1 is a diagrammatic view of the control circuits used in one embodiment of my invention. a

Fig. 2 is a diagrammatic view illustrating the optical system of a timing device embodying my invention.

Fig. 3 is a time-current curve showing the sequence of discharge of a pair of glow tubes employed in the practice of my invention.

Referring to Fig. 1 in detail, a line switch I is provided for controlling the connection of a two-pole split-phase synchronous motor 2 and a rectifier transformer 3 to a suitable 6O cycle source (not shown). An external condenser 4 is provided for producing quadrature phase energization of the motor 2, and the latter is provided with a suitable induction starting winding in accordance with the usual practice.

The rectifier transformer 3 is provided with a centrally-tapped plate winding 5, connected to the plates of a full-wave hot-cathode rectifier l, and with a filament winding 6 connected to the cathode of the rectifier l in the usual manner.

A filter 9, comprising a shunt condenser I l and a series reactor I3 is provided for reducing the harmonics in the output of the rectifier 1 and transformer 5 in accordance with the usual practice. Itwill be understood that the specific filter shown is illustrative only, and that the invention may be practiced with-any of a variety of such devices known in the art.

A potentiometer I5, comprising a pair of adjustably-tapped resistors ll connected in parallel to each other and in series to a third resistor I9, is connected to the output terminals of the filter 9. The potentiometer l5 normally draws a load current which assists in reducing the ripple in the direct current voltage in a manner well understood in the art.

A pair of condensers 2| and 22 are connected to the adjustable taps of the potentiometer IS. The condenser 2| is connected in parallel to a circuit which includes a glow tube 23, a resistor 25 and one pole of a high-speed two-pole manually-operated switch 21. The condenser 22 is connected in parallel to a similar circuit which includes. a glow tube 24,a resistor 26 and the contacts of a relay 30, under test. The energizing circuit for the relay 30 includes the remaining pole of the switch 21 and a source (not shown) suitable for energizing the relay under test.

The glow- tubes 23 and 24 are preferably of the two-electrode gas-filled type, having the usual charateristic of becoming conducting at a predetermined value of voltage, and remaining conducting after their initial impedance has been broken down, until a zero value of current occurs. The resistors 25 and 26 serve to limit the current which can flow from the corresponding condenser 2| or 22 when the associated glow tube 23 or 24, respectively, is in conducting condition. The potentiometer l5 supplies a maximum voltage considerably above the break-down voltage of the glow- tubes 23 and 24.

Referring to I-ig. 2, the glow tubes 23 and 24 are arranged to illuminate an inner dial 3| and an outer dial 32, respectively, on a disc 33 driven by the synchronous motor 2. The entire apparatus is preferably enclosed in an opaque casing (not shown) having windows for viewing the illuminated portions of the dials 3| and 32. An opaque stationary screen 34 is provided for preventing any crossillumination of the dials 3| and 32 by the glow tubes 24 and 23, respectively.

The operation of the above-described apparatus may be set forth as follows:' The switch is initially closed thereby energizing the transformer 3 and starting the synchronous motor 2. When the cathode of rectifier 1 becomes sufficiently heated, rectified current is supplied through the filter 9 to the potentiometer l5, and the condensers 2| and 22 become charged to voltages determined by the positions of the corresponding taps of potentiometer It.

To initially adjust the apparatus, the switch 21 is closed, thereby causing the closure of the relay 30. If the adjustments of potentiometer it: are such that the voltages applied tothe glow tubes 23 and 24 exceed their breakdown values, the glow-tubes 23 and M break down, thereby discharging the condensers 2i.

However, as soon as one of the condensers M is completely discharged, the voltage applied to the corresponding glow tube 33 or it becomes zero, and the initial impedance of the glow tube is reestablished thereby interrupting the condenser discharge current. The deenergized c0ndenser 2| accordingly re-charges exponentially at a rate determined by the resistances of the various paths through the potentiometer Hi. When the voltage of the condenser 2| again equals the break-down voltage of the corresponding glow tube, the latter again breaks down and the cycle repeats. If the voltage initially applied to either condenser 2| is insufficient to cause breakdown of the corresponding glow tube 23 or 24, this fact will be evident from a lack of illumination on the corresponding dial 3| or 32. The corre sponding tap of the potentiometer I5 is raised to a higher voltage position until breakdown occurs.

The glow tubes 23 and 24 periodically break down at frequencies determined by the positions of the corresponding taps of the potentiometer l5. By varying the positions of the potentiometer taps, a stroboscopic effect may be observed when the frequency of the glow tube circuit being adjusted approaches 30 cycles per second. Under these conditions, one flash of the glow tube occurs substantially at each revolution of the disc 33, and the corresponding dial 3| or 32 appears to be slowly rotating. The potentiometer taps are adjusted until both dials 3| and 32 appear to be stationary. When this adjustment is made, the switch 21 is opened, and a short time interval allowed to elapse in order to permit the condensers 2| to become fully charged.

To measure the time of operation of'the relay 30, the switch 2'! is reclosed. Upon closure oi"; the switch 21, the glow tube 23 breaks down substantially instantaneously, and a point on the inner dial 3| is illuminated and appears to be stationary because of the recurring flashes of glow tube 23. I

As soon as the relay 30 operates, the glow tube 24 breaks down and a portion of the outer dial 32 is similarly illuminated and appears station ary. The time which elapsed between the initial breakdowns of the glow tubes 23 and 24 appears as the diiierence of readings of the dials 3| and 32.

Fig. 3 illustrate". the character of the successive discharges in glow tubes 23 and 2 1. In this figure, the current impulses through the tube 23 are denoted by the reference character 23', and those through the tube 2d are similarly denoted by the reference character 24'. In order to produce clear definition of the dials, it is necessary that the impulses 23' and 24' be of short time duration. This requires that the resistors 25 and 25 be of comparatively low value, consistent with the safety of condensers 2i.

I do not intend that the present invention shall be restricted to the specific structural details, arrangement of parts or circuit connections herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In a timing device, an optical system cornprising an index and a pair di electric illuminat ing devices capable of producing light pulses of short time duration in response to predetermined condition of electrical energization, said. illuminating devices being arranged in optical paths with said index, timing means for causing said paths to sweep said index, initiating means i for producing said predetermined condition in said illuminating devices successively with a time diiierence dependent upon the magnitude of the time interval to be measured, and electric oscillating means effective upon operation of said ini tiating means to periodically energize said illu minating devices to said predetermined condition of energization, at the same frequency, with a phase difference corresponding to said time difference, whereby said time interval is translated to a distance interval between repeatedly illuminated portions of said index.

2. In a timing device, an optical system comprising an index and a pair of electric discharge devices capable of producing successive light pulses when energized by a periodically recurring electrical condition, said discharge devices being arranged inoptical paths with said index, timing means for causing said paths to sweep said index cyclically at a predetermined frequency, energizing circuits for said discharge devices ineluding individual oscillator means effective to produce periodically recurring electrical conditions of said predetermined frequency in said discharge devices, and means for initiating operation of said energizing circuits successively with a time difference dependent upon the time interval to be measured, whereby said time interval is translated to a distance interval between repeatedly illuminated portions oi said index.

3. In a timing device, an optical system comprising a rotary index and a pair of electric discharge devices capable of producing successive light pulses when energized by a periodically recurring electrical condition, said discharge devices bclng arranged to illuminate portions of said index, timing means for rotating said index at a predetermined frequenc energizing circuits for said discharge devices including individual electronic oscillator means effective to produce periodically recurring electrical conditions of said predetermined frequency in said discharge devices, and means for initiating operation of said energizing circuits successively with a time dii- 5. In a timing device, an optical system comprising a rotary index and a pair of glow discharge devices arranged to illuminate portions of said index, timing. means for rotating said index at a predetermined frequency, direct-current energizing circuits for said discharge devices including series resistance elements and shunt capacitance elements effective to produce periodically recurring discharges of said predetermined frequency in said discharge devices, and means for closing said energizing circuits successively with a time difierence dependent upon the time interval to be measured.

JOSEPH F. KOVAISKY.

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