US2125765A - Remote control system - Google Patents

Description

Aug. 2, 1938. H. E. BUTLER REMOTE CONTROL SYSTEM Filed April 9, 1937 Fig.

Patented ug. 2, 1938 UNITED sTATEs estan eral Electric Company, a corporation ci York New

Application April 9, 1937, Serial No. 135,@@7

a' crains.

My invention relates to remote control systems for electric circuits, and more particularly to a systemA for turning on, and 01T, lamps in a street lighting system.

One object of my invention is to provide an improved system and apparatus for controlling street lamps from a central station without the use of a pilot wire.

For further objects and advantages of my in1 vention, reference is had to the following description when taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the accompanying drawing, Fig. l is a cliun cuit diagram indicating the connection and operu ation of the apparatus included in my invention. Fig. 2 illustrates an assembly oi my apparatus, and Fig. 3 illustrates the control switch used in the system, the connection diagram of which is illustrated in Fig. l.

Referring to the drawing in detail, Lhave shown. in Fig. 1 a diagram of a system including a transformer 5 comprising a primary Winding ti and a secondary winding I. The secondary winding is provided with a series of taps 3, t, and IIB which are placed at different potential points in this,

winding, and by means of a switch il, `cooperating with these taps, the potential across conductors I2 and I3, constituting the supply circuit, may be varied. The apparatus connected across the supply lines I2 and I3, which is to be remote controlled, is a lamp I@ which I have diagrammatically illustrated. One terminal oi' the lamp is connected through a conductor I5 to the supply conductor I2, and the other terminal is connected, by means of a conductor i6, to one terminal I'I of a switching device Ill. A second tenminal I 9 of the device I 8 is connected through conductors and 2I to the second supply conductor I3. A heater 22 of the device I8 is perf manently connected to the supply conductors IZ and I3 by means of the conductors I5 and 2 1 In Fig. 2, I have illustrated a cross sectional view of the top of a conventional lamp post in which the lamp I4 and the control device I8 are assembled. The lamp I4 is mounted in a socket 23, which is adjustably supported by brackets 2d Vand 25 mounted on a suitable flange within the post 2S. The device I8 is mounted in a cradle 2l directly below the lamp I6, and within the post 25. A Window 28 mounted in the post 26 affords a View of the heating element 22 of the device It.

In Fig. 3, I have illustrated in detail the switching device I8 comprising contacts I'I and I9 oper-l able by a thermal responsive element 29 and exposed to the temperature ci the heating element 22. The heating element as shown in Fig. i, is connected across the supply conductors it and I3, and comprises a resistance element, preferably a filament oi tungsten. temperattue oi this filament varies in accordance with the poten`1 tial variations across the supply source conductors I2 and It. 'lhe thermal responsive elem ment 29 comprises a bimetallic dislr which as sumes one position when heated above a prede termined temperature, and assumes another posi.m tion when its temperature falls below this value to a second predetermined value. Temperatures between these two values do not effect moera-n tion of the disk. 'Ihe two positions are iilustrated in Fig. 3. The iull line position is assumed when the temperature of the iilament 22 falls below the critical value, and in this position, the contacts il and I9 are brought into engagement, the contact il being mounted upon a resilient arm which is connected through a rod 3l to the ce ter of the bimetallic disk 2&3. A circuit is therecy estabN lished from a terminal 32 through conductor to the resilient arm 3B, and through the contacts il and I9 to a conductor 34 and a term The heating element 22 is connected throng.. con. ductors 36 and 3l to terminals 38 and rr with' the terminals 32 and B in a base fifi. :le entire assembly is mounted within an evacuated receptacle 4i in which the contacts are protected. from corrosion.

In the operation ci street lighting luminaires, becomes expensive to install pilot wires leading from the lamps to a central station for the con trol of switches which will turn on, or oit, the current to the lamps. It is also inconvenient extend the circuit to which these lamps are conu nected to the power house. It is permissible, hown ever, to vary the supply line voltage of these cirw cuits to which apparatus or lamps other than the street lighting lamps are connected as much as 10% above or below the rated value. Such variation of the voltage can be eiiected at the central station in many, different ways. The thermal responsive switch illustrated in Fig. 3 and more fully disclosed and claimed in my U. S. Patent No. 1,982,368 is operable between its two positions by a variation of 10% above or below the normal value, and has the additional advantage of being unaffected by a continuous operation of the heating element at rated voltage. In accordance with my invention, therefore, I provide each' of the lamps in the luminaire which is to be controlled, with a. switch of this type and permanently connect the heating element across the supply conductors for the lamps. When it is desired to connect the lamps into the circuit, it is only necessary to lower the line voltage at the source, and maintain this lowered line voltage for a period o! time, approximately one or two minutes, during which the heating element of the switch, and consequently, the thermal element, reduces its temperature and assumes the i'ull line position indicated in Fig. 3. The time period chosen is of such length that the slowest of all the switches on the line is given suillcient time to operate. After this period, the voltage may be increased to normal value, and although the heaters 22 of the thermal elements 28 reach a higher temperature, the temperature is insumcient to cause an operation thereof to the second position. When it is desired to disconnect the lamps from the circuit, it. is only necessary to increase the line voltage above the normal value for a predetermined time period, thereby increasing the temperature of the thermal element and causing it to assume its second position, at which the contacts I1 and I9 are separated. A subsequent reduction of the line voltage to normal rated value is again insuillcient to result in an operation of the thermal element, and, therefore, the lamps Il remain disconnected from the circuit.

In Fig. 1, I have illustrated diagrammatically the simplest form of changing the voltage between the line conductors I! and I3, consisting o! tapped winding 1 and switch II. When the switch II is moved to contact t of the winding 1, potential oi' the supply line is increased approximately 10% above normal, and when the switch II is in engagement with the contact III, the line voltage is reduced approximately below normal. Normal voltage is obtainedwhen the switch I I is in engagement with the contact 9. It is, of course, possible to use any other means for varying this line voltage. Furthermore, although I have illustrated my invention as being applied to street lighting circuits, it will be obvious to those skilled in the art that the invention can be applied to the control o! any other electrical device for which it is found objectionable to supply a separate control wine. It may be noted here that although only 10% variation in voltage is required to operate the device Il, the device will not be operated by iluctuations in line voltage` which may occur due to changes in load, because the particular change in line voltage necessary for operating the switch must continueover a dennite period of time. As stated above. this period of time ranges from one to two minutes, but may, of course, be adiusted'in accordance with the needs oi' a particular transmission circuit.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an electric power distribution system, the combination of a single power circuit. a power consuming device, a switch operable to connect and to disconnect said device from said circuit. means responsive to predetermined' changes in voltage oi' said circuit for respectively operating said switch to connect and to disconnect said device, and means for producing the said Ichanges in voltage ofl said power circuit to effect the operation of said switch.

2. In an electric power system the combination of a single circuit, a power consuming device, a switch operable to connect and disconnect said device from said circuit, mleans for operating said switch including a heater connected to and responsive to the voltage of said single circuit, a

,thermostatic disk operable to one position when heated to one temperature and operable to a second position when heated toa second and lower predetermined temperature, and means for varying the voltage of said circuit to effect a heating of said element to either of said tempii'tllires and a corresponding operation of said s c 3. In a street lighting system, the combination of a single power circuit, means for changing the voltage on said power circuit above and below a predetermined value, a street lighting unit, a switch operable to connect said unit to said power circuit, and means for operating said switch comprising a heating element the temperature of which is responsive to the voltage on said power circuit, and a thermal element connected to operate said switch to connect said unit to said circuit when the voltage on said power circuit remains for a definite period of time at a predetermined value above rated value, and to disconnect said unit from said circuit when said voltage remains for a deiinite periodI of time below the rated value, and to maintain said switch in either of said operating positions when said power circuit voltage remains at normal value.

HENRY E. BUTLER..

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