US2262650A - Alarm system - Google Patents

Description

Nov. 11, 1941.

M. E. REAGAN arm. 2,262,650

a: ALARM sysml Filed Sept. 8, 19:58

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' WITNESSES: INVENTORS Maurice Kenyan and f/v/as Michel. BY

Patented Nov. 11, 1941 ALARM SYSTEM Maurice E. Reagan. Wilkinsbnrg, 2a., andMathiag Michel, Wauwatosa. Wla, asslgnors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa a corporation of Penny]- vania Application September 8, 1938, Serial No. 228,932

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Our invention relates, generally, to alarm systems, and it has particular reference to a multiple point alarm system for use in power stations and the like.

It may often be found desirable to provide a signal and alarm system for indicating at a central point in a power station not only the operation of, but also the instantaneous operating condition of, a number of devices. This is particularly so with alarm systems which are used in connection with a number of protective devices, such as bearing temperature relays, oil pressure indicators, etc., for safeguarding equipment in a power station or the like. Any or several of the protective-devices may operate under certain circumstances, and they may remain in the operated position, or may subuquently return to the normal or inoperated position, should the fault be removed. It is, therefore, desirable that a system used with such an installation should be capable not only of operating an alarm device immediately upon the functioning of some protective device to warn an attendant, but it should furthermore provide an indication of the instantaneous operating condition of each such device. Moreover, it may also be found desirable to use in connection with such an installation a single alarm device, and in such a manner that the alarm device may be located nearby the attendant, by whom it may be reset after it has operated, to render it responsive to notify him of subsequent operations of others of the protective devices, without first requiring him to reset such protective devices as may have already operated.

It is, therefore, generally, an object of our invention to provide a simple and eifective manner for indicating the operating condition of a plurality of separate devices.

More specifically, it is an object of our invention to provide an energy impulse alarm system for indicating at a central location the successive or simultaneous operation of a plurality of protective devices and giving an alarm signal.

Another object of our invention is to provide for automatically indicating at a central point in a station the operation of, and the instantaneous operating condition of, a plurality of protective devices which may be located at various points about the station.

A further object of our invention is to provide a simple and effective manner for effecting energizations of a signal alarm from a plurality of separately located control devices without requiring resetting of an operated device to render the alarm device responsive to subsequent operations of the other control devices.

Other objects will. in part, be obvious, and

' will, in part, appear hereinafter.

In practicing our invention, a single signal alarm device may be energized upon the operation of any of a plurality of protective devices which may be located at various points about a station, through the closure of normally open control contact members associated with any of the protective devices to connect a condenser to the control circuit of the alarm device and thereby release an impulse of electrical energy therethrough of suillcient value to operate an alarm relay. At the same time, indicating means, such as a lamp or the like, may be connected through the control contact members to a source of energy so as to provide a visible indication while the control contact members remain in the closed position, thus showing at a glance the instantaneous operating condition of each protective device. Unidirectional current means may be provided to prevent the discharge from any of the condensers from being diverted through the already closed contact members associated with any other protective device, so that if the alarm device is reset after operation, the subsequent operation of any other protective device to close its control contact members and connect the condenser associated therewith for discharge through the control circuit of the alarm device will be effective to energize the alarm device.

For a more complete description of the nature and scope of our invention, reference may be had to the following detailed description, taken in connection with the accompanying drawing, in which the single figure represents diagrammatically a signal system embodying a preferred form of our invention.

Referring to the drawing, it will be seen that the reference numeral il denotes generally an alarm system wherein a single alarm device or bell I! may be connected to a source of energy I, through the operation of an alarm relay II.

In order to eflect the desired energization of the alarm relay I having an operating winding 2| upon the operation of any of a plurality of protective devices, such as a bearing thermostat\/ relay or the like (not shown), having control contact members 26, which may be located at various points ll about a power station, a plurality of condensers ll may be provided, each disposed in series circuit relation with an indieating means such as the lamp II, and a current limiting control resistor 22 for energization from common control buses 23 and 24. The circuit may be traced from one terminal of the condenser II, through contact members 2!, a unidirectional current device 30, the purpose of which will be explained later, conductor 32, operating coil 2|, conductor 33, andbus 24, to the opposite terminal of the condenser II.

The normally open contact members Ila of'th'e alarm relay It close upon operation of the relay toconnect the alarmbell IZtoasourceoi' energy, such as the battery II, and so give an indication to an attendant or the operation of the particular protective device which is associated with the control contacts 2|. At the same timealosure oi the normally open contact members "D of the alarm relay may complete a holding circuit for the relay from the bus 22, through a current limiting resistance 25, contact members lib, operating coil 2|, conductor 22, to bus 24. The alarm bell will then continue to ring and warn the attendant oi the opera.- tion of the protective device associated with the contact members 20, until the alarm relay is deenergized by the attendant closing the normally Open push button 26, which provides a shunt path about the operating coil 28. .Upon deenergization oi the alarm relay, the contact members Ila and [6b open, disconnecting the alarm device 12 from the source and interrupting the holding circuit of the relay.

In order to prevent the alarm relay it from then being immediately reenergized should the control contacts 28 remain closed, by the flow of current through the path from the bus 23, through control resistor 22, indicating lamp 20, control contacts 26, unidirectional current device l0, conductor 32, and operating coil 28, to bus 24, the control resistor 22 may be so designed as to limit the current flow through the indicating lamp to a value sufficient to light the lamp, but below that required for the operation of the alarm relay i8.

The unidirectional current devices 3|! are disposed in series circuit relation between the control contact members 26 and the conductor 22 for preventing the discharge from another of the condensers it upon it being subsequently connected to the alarm relay by closure of its associated control contact members 26, from being diverted through the control contact members 26 of a protective device which has previously operated and which may have remained in the closed position. Thus the diversion of such discharge from the operating coil 28 is prevented and the alarm relay may respond to the subsequent closure of any of a plurality of the control contact members 28, regardless of the fact that the contact members 26 of others oi! the protective devices which had previously operated may have remained in the closed position.

From the above description it may be seen that we have provided through our invention a simple and effective manner for providing both instantaneous warning or the operation of, and continuous indication of the operating condition of, a plurality of protective devices through the use of a signal alarm device. The system herein disclosed by us readily provides for the indication at a central point in a station of the ope ation condition of a plurality of protective devices, may be safely used with existing relatively high voltage control buses, and contains no complicated and expensive control devices which might be subject to failure. thus making it e onomical to install and easy to maintain. While we have preferred to illustrate this embodiment 01' our invention in connection with a plurality of protective devices, it may be realized that our invention may also be readily and effectively utilized in any other suitable manner.

Since certain changes may be. made in the above construction and diii'erent embodiments oi I the invention may be made without departing from the spirit thereof, it is intended that all the matter contained in the above description, or shown in the accompanying drawing, shall be considered as illustrative, and not in a limiting sense.

We claim as our invention:

1. An alarm system comprising, alarm means, capacitor means normally charged by a source of direct current, contact means operable to connect the alarm means to the capacitor means to effect operation oi the alarm means therefrom, and indicating means effective upon operaation oi the contact means to give visual indication 01 the operation of the contact means,

2. An alarm system comprising, indicating means, an alarm relay for controlling an alarm device. a condenser normally charged from a direct current source, and control means operable to contact said condenser to the alarm relay to elect a single operation oi the alarm relay therefrom and provide or energization of the indicating means.

3. An alarm system comprising, an alarm device, a relay for controlling the energization of the alarm device, indicating means, a condenser, means connecting the condenser, and indicating means to a source of direct current in series circuit relation, control means operable i'or etlecting connection of the condenser in shunt circuit relation with the relay to provide a surge of electrical energy for eflecting a single operation of the said relay, circuit means for retaining the relay in the operated position, and means for releasing the relay from the operated position to render it responsive to subsequent surges of electrical energy, the impedance of said indicating means being eiiective to limit the current through the relay while the control means remain in the operated position to a value below that required for operating the relay.

4. A multiple point alarm system comprising, a plurality of normally charged capacitor devices connected to a source of direct current, a plurality of indicating means, alarm means, control means associated with each of said capacitor devices operable on predetermined condition to connect the capacitor device to the alarm means to eflect an operation of the latter, and unidirectional current means connected in series circuit relation with each control means to prevent diversion therethrough of a subsequent discharge 01' energy from any 01' said capacitor devices.

5. An alarm system comprising, an alarm device, a control relay operable to eilect the energization of the alarm device, a plurality of condensers connected for charging in shunt circuit relation with a source of direct current, an indicating means connected in series circuit relation with each condenser, control means operable to connect each condenser in shunt circuit relation with the control relay for eflecting a single operation thereof to energize the alarm device and providing an energizing circuit for said indicating means, and a unidirectional current device connected in series circuit relation with each of said control means for preventing a subsequent discharge from one of said condensers from being diverted from the control relay.

MAURICE E. REAGAN. MATHIAS mCHEL.

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