US2046622A - Supervised electric system - Google Patents

Description

July 7, 1936. H. c. GRANT, JR

SUPERVISED ELECTRIC SYSTEM Filed Sept. 22, 1934 L 'WM GMW ATroRNEY Patented July 7,

. 2,046,622 sursavrsnp aanc'ralo SYSTEM Harry Campbell Grant. Jr., New York, N. Y.. as-

signor to Walter Kiddo 8; Company, Inc., Bloomield, N. J., a corporation oi New York Application September 22. 1934, Serial No. 745,090

3 Claims.

rIhis invention relates to alarm systems, for

Vilre, for burglary, and so forth, of the type in which a plurality of external circuits, each containing one or more normally closed circuit opening devices, are connected in series with a no-load relay and a source of electric potential, whereby the opening oi the circuit at any point, due to a re condition or burglary, is indicated at a central alarm station. 4

Previous systems of the type described have been objectionable because of the need for an alarm relay for each of theseveral external circuits. Such a system, for instance, is shown in Letters Patent of the United States No. 916,280, granted March 23, 1909. Another objection to previous systems has been incomplete supervision against various kinds of trouble which may be encountered under conditions of actual service.

It is therefore the primary object of the present invention to provide a ilre alarm system of the type referred to which will meet the public demand for a simple and eillcient system, and which at the same time is fully supervised against any troubles which may develop.

The present invention is generally similar to that shown and described in my copending application of the United States, Serial No. 572,783.

-- illed October 23, 1931; but differs therefrom in the provision of simpler means for locating the external circuit or circuits from which a re Bisnal has been relayed to the central ilre alarm station, it being unnecessary to search for the circuit in alarm by operation of various switches as provided for in my earlier application.

It is therefore another object of the present invention to provide a closed circuit ilre alarm system in which simpler means is provided to either by a main source of electrical potential,`

or by a secondary source of electrical potential normally under charge from the main source, the system likewise being capable of energization simultaneously by both of the sources of potential.

It is also an object of this invention to indicate failure of the. main source of electrical energy. It is a further oblect to indicate failure of the secondary source of electrical energy.

It is a still further object to completely supervise the external circuits against grounds and to provide means to remove the grounds so as to avoid dangerous conditions which would otherwise occur.

A still further object is to provide means to 5 scribed in greaterdetail in connection with the lo accompanying drawing, in which the single iigure is a diagrammatical representation of an alarm system constructed and arranged in accordance with the invention.

In the system shown the reference numerals l and 2 represent the positive and negative terminals of a secondary source of electrical potential in the form of a battery 3, which is protected by fuses 4 and 5 and which is normally under charge, in a manner hereinafter to be described. from a main source of electrical energy, the positive and negative terminals of which are shown at 6 and 1.

At A therel are shown the terminals of a socalled extemal circuit containing normally lclosed circuit opening thermostats 8. B and C` indicate the terminals of additional external circuits, all of which are connected inv series in the following manner; current flowing from the positive line through the wir 9, the ground detector 30 the external circuit C, switch it, wire I t, switch 35 llc, circuit lamp IBC, wire i9, switch il, circuit lamp lab. wire 20, switch il, circuit lamp IB, wire 2|, the ilre alarm relay 22 and the wire 23 to the negative line. The electrical characterfistics of the various elements in the series circuit 40 are so chosen that the current normally ilowlng in the circuit is of a value insuillclent to illuminate the circuit lamps, the current however being of a suillcient value to energize the nre alarm relay 22 and serving as a supervisory current for 45 the various elementsin said series circuit, the relay 22 being a circuit supervisingv relay as well as a fire alarm relay.

The circuit just described and the battery l are connected in parallel with the main supply 50 terminals B and 1, the latter normally supplying the energizing current for said circuit and the charging current for the battery, the positive and negative junction points being at 24 and 2l.

-The path of the charging current for the bat- Ctery is from the main supply terminal 8 through n the armature 28 of the main supply supervising relay 2li the contact 28, the charging resistances 28 and 30, the wires 3i andv32, through the battery, the wires 33, 34, 35,-38, 31, and 38, the ar` mature 38, the contact 48, and thewires 4I and 42 to the main Supply terminal 1. y

At 43 is shown the battery supervising relay vwhich is connected to the positive terminal of the battery by wires 32 and, and to the negative terminal of the battery by the wire 45.

When a system in accordance with the present opening ofthe reset switch 48, which is there-` fore preferably of A` the push-button type, the main supply supervising relay 21 will be found to be connected across the main supply terminals 8 and 1 through the armature '28, the contact 28, the wire 48, the armature 50 of the ground detector relay I0, the contact 5I, the wire 52, the resistance 53, the wires 41', 48, and 38, the armature 38, the contact 48, and the wires 4I and 42, thus holding the relay 21 energized.

By reason of the herein-referred to ilow of current through the external circuits from the junction point 24 to the junction point 25, the iire alarm relay 22 is normally energized,` but'as soon as a fire occurs in a space protected by an externall circuit, as for example in the space indicated by the thermostat 8 on the external circuit A, the circuit between the `iunction points 24 and 25 is broken by the opening ofthe thermostat, whereby the re alarm relay 22 is deenergized. This results in the closing of the contacts 54 and 55 by the armatures 58 and 51, whereupon fire alarm signals are rendered in the following manner.

This gong is sounded by reason of current flowing from the positive line through the wires 58, 88, and 8l, the contact 55, the armature 51, switch 98', wire 88, and the wire 23 to the negative line. `At the'same time the ilre alarm lamp 82, normally located at the central ire alarm vided a second ilre alarm gong 84 which be- As soon as the presence of fire is made knownby any one or more of the means provided, the

nre-watch attendant immediately proceeds to the central fire alarm station, at which point he will find on the operating panel the already referred to switches I4", I4", I4'=, I1, I1b, and I1`, all of The reference numeral 58 represents the iire alarm gong which is nor-l l mally located at the central fire alarm station."

which are two-position switches. He will 4also l11nd the normally open switches 88, 88h, 88, 10,

and 18. All that it Lis necessary for theV ilrewatch attendant to dois to throw all of the twoposition switches from their one position to the other and to close all of the herein-mentioned normally open switches.

If no fire has occurred in any of the spaces protected by the external circuit A, so that -no thermostat has operated on this circuit. no indi- 10 cation will be given by lthecircuit lamp I8, as both sides of the circuit lamp will be found to be connected' to the positive line; the one side through the wire 8, the ground detector relay I8, the resistance Il, and the-switch 88"; and the 15 other side through the wire 8, the ground detector relay I8, the resistance Il, vthe external circuit A, the switch I4, the contacts 1I* and 12, and the switch I1. If, however, ilre has occurred in one of the spaces protected by the 20 external circuit A, so that one of the thermostats 8 on the external circuit Ahas operated to open the circuit, the last referred to connection n of the one side of the circuit lamp I8*l to the positive line throughkthe external circuit A itself 25 would not be completed, because of the open circuit caused by the operated thermostat 8. The circuit lamp I8 is then illuminated by reason of the ilrst mentionedconnection of the lamp to the positive line and by reason of its connection 30 to the negative line through the switch I1, the contact 12, .the wire r13, the resistance 14e, and the wires 34, 35 and 35, thus indicating that a' thermostat has been operated on the external circuit A. The resistance 14' is a. current con- 35 suming resistance which `has its principal use when both sides lolf the circuit lamp I8 are connected to positive in the manner already de scribed.

Similar indications are given in connection 40 with the external circuits B and C, the corresponding switches, lamps and current consuming'resistances being indicated by similar reference numerals. 1

If no re has occurred in any of the spaces 45 protected by the external circuit B, so that no thermostat has operated on this circuit, no indication will be given by the circuit lamp I8b, as both sides. of the circuit lamp will be found to be `connected to the positive line; the one sideY 50 through the wire 8', rthe wire 8", the switch 18,

' the wire l5 and the switch 89h; and the other side through the wire 8', the wire 9", the switch 18, the wire I5, the external circuit B, the switchv I4b, the contacts 1Ib and 12b and the 55 switch I1b. If, however, fire has occurred in one of the spaces protected by the external circuit B, so that one of the thermostats 8 on the external circuit B has operated to open the circuit, thelast referred to/connection of the one 60 side to the circuit lamp I8bto the positive line through the external circuit'B itself would vnot be completed, because of the open circuit caused by the operated thermostat 8. The circuit lamp lsb is then illuminated by reason of the iirst G5 mentioned connection of the lamp to the positive line and by reason of its connection to the negative line Ithrough the switch I1, the contact 12b, the resistance 14h, and the wires 35 and 38, thus indicating that a thermostat has been operated 1 on the external circuit B. The resistance 14b is a current consuming resistance which has its principal use when both sides of the circuit lamp I 8b are connected to positive in the manner already described.

2,048,622 If no fire lhas occurred in any of the spaces protected by the external circuit C, so that no thermostat has operated on this circuit, no indication will be given by the circuit lamp 18, as both sides of the circuit lamp will be found to be connected to the positive line; the one side through the wire 9', the wire 9"', the switch 10b, the wire 15b and the switch 69; and the other side through the wire 9', the wire 9"', the switch 18h, the wire I5", the external circuit C, the switch Isc.. the contacts 1| and 12, and the switch 11. If, however, flre has occurred in one of the spaces protected by the external circuit C, so that one of the thermostats 8 on the external circuit C has operated to open the circuit, the last referred to connection of one side of the circuit lamp 18 to the positive line through the lexternal circuit C itself would not be completed,

because of the open circuit caused by the operated thermostat 8. The circuit lamp I 8 is then illuminated by reason of the first mentioned connection'of .the lamp to the positive line and by reason of its connection to the negative line through the switch I1, the contact 12, the resistance 16, and the wire 3B, thus indicating that a thermostat has been operated on the external circuit C. The resistancel 14" is a current consuming resistance which has its principal use when both sides of the circuit lamp 18 are connected to positive in the manner alreadyy dehave all of the switches operated automatically upon the opening of the control cabinet door.

It will, of. course. be understood that the occurrence of a wire break in any of the external circuits will turn in ilre alarm signals, but the existence of a wire break will not become apparent until after an unsuccessful search for the presence of ilre on the circuit indicated, Vthe same condition holding whenever a circuit lamp burns out, or whenever any other element in the supervised alarm circuit falls.

Testing of any one of the external circuits can be accomplished by opening the test switches provided in the various circuits. For the external circuit A" the test switch` is shown at 15. Although the test switches can be employed to test simply the operability of the central station fire alarm apparatus, the primary object of the test switches isto locate short-ciruits of the external circuit leads which would prevent operation of the central station ilre alarm apparatus by thermostats more remote from the central station y than the existing short-circuit. Accordingly a test switch is placed at the most remote point of each of the external circuits; and failure of the central station fire alarm apparatus to function upon opening of a test switch is an indication of a short-circuit in the particular external circuit tested. It should be noted that short-circuits'of the external circuit leads can not be detected automatically but only by manual test, as the external circuits have no current limiting resistances and therefore a short-circuit has the same resistance as the normal line circuit.

It has already been mentioned that the external circuits are protected against the occurrence of grounds, and the relay I0 has already been referred to as the ground detector relay, which relay is normally not energized by the relatively small supervisory current which flows through the external circuits from the junction point 24 to the junction point 25, the voltage drop across the relay I0 and the resistance Il being only a fraction of the total drop from the Junction points 24 and 25 by reason of the far greater resistance of the fire alarm relay 22 in the same series circuit.

It is customary in ship installations to have the ship's electrical circuits ground clear but this condition rarely exists. At times the ship's negative may be grounded and shortly after this the ground may be changed from negative to positive. The relative position of the ground on a ship's generator and various points of the circuit in accordance with the present invention will cause different indications to be given at the central control station.

In order to clarify the discussions which follow, let it be assumed, by way of example, that a ship has a 220 volt supply and that the battery 3 of the present invention is a 40 volt battery.

If, therefore, any one of the-wires of any of the external circuits becomes grounded, while at the same time the positive side of the main power supply is normally grounded, a much greater than normal voltage is applied across the ground detector relay I0 and the resistance il, whereupon the ground detector relay is energized and the contact at 5I is opened. 'I'he opening of the contact 5I directly interrupts the already described energizing circuit of the main supply supervising relay 21, whereupon the latter is de-energized, opening the contact at 48, and closing the contact at 16. 'I'his action results in the sounding of through the trouble gong 11 and the trouble lamp 18, then through the wires 84 and 85', the contact 18, the armature 39, and the wires 38, 31, 38, 35, 34, and 33 to the negative terminal of the battery. The sounding of the trouble gong 11 can be stopped by opening the normally closed switch 9|, but the trouble lamp will remain illuminated until the trouble has been repaired.

If, on the other hand. any one of the wires of Vone of the external circuits should become grounded, while at the same time the negative side of the main power supply is normally grounded, the ilre alarm relay 22 will be short-circuited, whereby the full normal voltage between the junction points 24 and 25 will be applied across the ground detector relay I0 and the` resistance li, whereby the ground detector relay is energized andthe main supply supervising relay 21 is de-energized in the manner already described in connection with the occurrence of a ground when the positive side of the main power supply is normally grounded. The already mentioned shortcircuiting of the flre alarm relay 22 results in its momentary de-energization, but this relay will again be energized and the ground detector relay i0 will be de-energized when the ground is removed in the manner about to be explained.

Although it is one of the purposes of the main supply supervising relay 21 to indicate the failure of the main supply, whereby the relay would be de-energized and the trouble signals given in the manner already explained. the most important function of the relay 21 is to break the circuit between the fire alarm systenfand the main supply on both sides, thus removing the ground and allowing the battery to re-energize the fire alarm relay 22, so that dangerous currents often flowing for ground conditionslwill be interrupted. For this reason the relay 2'1 is not arranged to pick up on the main supply voltage directly, but, if de-energized, is required to be reset manually by the reset switch 48, as otherwise, upon de-energizatlon of the relay 21 due to a ground with consequent breaking of the ground circuit, the relay 21 would be 17e-'energized and thus bring back the ground, with the result that the relay would buzz rapidly and burn off eitherof the contacts 28 or 40, depending on the relative location of the grounded points.

The relay 21 has also a third function, which.

is best mentioned at this time, in that the breaking of the circuit between the re alarm system and the main supply upon failure of the main supply prevents the battery from discharging back into the main supply lines, the battery now serving as the main and only source of energy. l

In view of the fact that the auxiliary re .alarm gong 641s normally located at some distance from the central flre alarm station, defects can easily occur in the external leads to the auxiliary fire alarm gong, and thisV gong is accordingly supervised by means of the auxiliary gong supervising relay 92, current flowing from the positiveline through the wire 59, the external gong leadl 66, the auxiliary fire alarm gong 84, the fuse 88. the wire 61, the auxiliary gong supervising relay 92, and the wires 89, 90, and 28 to the negative lin'e.

If now the main supply is normally grounded on the negative side, and if Va ground occurs in the external gong lead 85', the auxiliary gong supervising relay 92 will be short-circuited and consequently de-energized, whereby the armature 88 will close the contact 81, and the trouble gong and trouble lamp will be operated by .reason of current flowing from the positive line through the trouble gong and trouble lamp in parallel,

the wires 84, 85, and 88, the contact 81, the armature 88, and the wires 89, 90, and 28 to the negative line. At the same time the auxiliary gong 64 will sound due to the cutting out of the high resistance of the supervising relay 92. If,

'. however, a ground occurs in the external gong lead 65, such ground will constitute a direct shortcircuit across the battery 3 and one of the fuses 4 and 5 will blow out, whereupon the battery supervising relay 43 will be energized and will Agive the trouble signal in a manner hereinafter tofbe described.

If, instead of the main supply linebelng nor- V .mally grounded on fthe negative side, it is norif the external gong lead 65 becomes grounded,

the increased voltage on the entire system will cause the battery supervising relay 43 to be energized and the trouble signal given in a. manner hereinafter to be described. At the same time theabnormally high charging current will cause one of the fuses 4 and 5 to blow, thus protecting the battery against excessive charge.

Theexternal gong leads are not only protected against grounds in the manner already described, but likewise against direct short-circuits of the leads. Such a short-circuit is normally undetected, but yas soon as a re alarm signal is given, the short-circuit of the auxiliary gong leads constitutes a direct short-circuit of the battery, whereupon the fuse 66 or one of the battery fuses 4 and l5 will be blown out, and the battery supervising relay 48 will be energized and the trouble signal given in a manner now about to b e -5 described. y

, While the main supply supervising relay 21 is normally energized, the battery supervising relay 43, which is connected across the terminals of the battery 3, is not energized by the normal battery voltage, but is designed to energize. upon r a considerable increase in voltage across the relay by the alarm gongs is greater than can be supplied by the main supply. The charging current normally owing into the battery therefore re- 25 verses itself and the battery supplies the excess current required when alarm conditions arise.

If now the battery should fail for any reason, not only will the battery supervising relay 43 be v energized; and give the trouble signals, but a por- 30 f non of the charging resistance '2sso will be cut out of the main supply line, so that the main supply will be capable of supplying the increased cui'-, rent required when alarm conditions arise.

The battery supervising relay4 43 is energized 35 upon failure of the battery, both'when the system is in its otherwise normal condition and when fire alarm' or trouble alarm conditions exist. The manner in which the battery supervising relay is thus energized will be better understood if it is 40 kept in mind that the voltage across the relay winding is normally the same as the voltage across the battery and across the external circuit between the junctions 24 and 25. In the system'n herein described, the resistance of the external 45 circuit is considerably greater than the internal resistance of the battery, and is also somewhat greater than the value of the charging resistance 29-30. It also happens that in the system de scribed the internal resistance 'of the battery is 56 "i less than the value of the charging resistance 29-30. When, therefore, the battery fails for any reason with the substitution of practically infinite resistance infplace of the normally small internal resistance ofthe battery, a considerably increased 55 voltage drop will occur across the external circuit, due tothe fact ythat removal of the battery charging current load will reduce the voltage drop across the charging resistance 29-39, and this increased voltage, occurring likewise across the winding of the relay 48, will cause the relay to pick up its armatures 93 and 94 and close the contacts at 98 and 9,6. The trouble signals will then be given by reason of current flowing from the positive line thromgh the trouble gong and trouble lamp in parallel, the wire 84, one side of the switch 9|, the resistance 98, the wire 99, the contact 98. the armature 94, and the wires 94' and 42 to the main supply terminal 1. Instead, however, of the connection from the main supply ter- `minal 6 being through the charging .resistance 29--39. the'increased current which the main supply is called upon to supply when the re or trouble gangs are sounded, requires that part of the charging resistance be by, and it will 75

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