US 1767582 A
Description (OCR text may contain errors)
June 24, 1930. A. w. FISHER 1,767,582
APPARATUS FOR THE CONTROL OF ELECTRIC LAMPS Fild July 7. 1921 INVENTOR'.
Patented June 24, 1930 uNrrEo STATES PATENT OFFICE amnion. w. manna,
RATION OF PENNSYLVANIA FOREST HILLS BOROUGH, PENNSYLVANIA, ASS IGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF
SWISSVALE, PENNSYLVANIA, A COB-PO:
APPARATUS FOR THE CONTROL OF ELECTRIC LAMPS Application filed July 7, 1927; Serial No. 208,965.
My invention relates to apparatus for the control of electric lamps, and particularly to lamps which are supplied with current from primary batteries.
I have found that when a battery, such as that of the caustic soda type, stands on open circuit for a considerable period of time, the battery develops the flow of current has continued for a short time. When an electric lamp is supplied with voltage from a battery of this character and the circuit is so adjusted that the final or normal voltage of the battery is the correct voltage for the lamp, the initial voltage supplied to the lam after the battery has been on open circuit or a considerable period of time tends to reduce the life of the lamp. One feature of my invention is the provision of means operating when the 'circuit for the lamp becomes closed to prevent the supply of excessive current to while the voltage of the battery is dropping to its normal value.
I will describe one form of apparatus embodying out the novel features thereof in claims.
' The accompanying drawing is a diagrammatic view s owing one form of apparatus .30 embodying my invention.
Referring to the drawing, the reference character B designates a battery, the voltage of which rises above its normal value when the battery is on open circuit for a consid- 85 erable period of time. This battery supplies current toan electric lamp L, through a circuit which includes a normall of a relay R. The circuit or the relay R, which circuit is designated by the reference character'Q, may be controlled in any suitable manner; for example, relay R may be the well known approach lighting relay used in railway signahn systems of the type wherein t e signal am s are normally extinguished and'become ighted upon the approach of a train.
The circuit for the lamp L also includes an operating windin 3 of .a thermostat T havin a normally c osed contact 4 and a norma ly open contact 5. When the thermoan initial voltage that is considerably higher than the voltage after the lamp my invention, and will then point;
open contact 8 stat T becomes energized by the supply of current .to its operating winding 3, an interval of time elapses during which contact 4 remains closed, and after the expiration of such interval of time contact 4 opens and contact 5 closes. While contact 4 is closed, a relatively high resistance 6 is included in circuit with the lamp L, and when contact 5 is closed, a relativel low resistance 7 is included in circuit wit the lamp L;
-The operation of the apparatus is as follows: Assuming that contact 8 of relay R has been opened for a considerable period of time, contact 4 of thermostat T will be closed, so that when contact 8 closes, the relatively high resistance 6 will be included in series with the lamp L, andthis resistance prevents the supply of an excessive amount of current to the lamp L while the voltage of battery B is dropping to its normal value. After the lapse of aperiod of time sufficient to enable the voltage of battery B to reach its normal value, contact opens and contact 5 closes, thereby removing the high resistance 6 from the circuit of lamp L and insertin the low resistance 7 in this circuit. The big 1 resistance 6 therefore prevents shortening of the life of the lamp L due to the excessive voltagede'veloped by the battery B for a short period of time after the circuit forthe lamp becomes closed at contact 8.
' I have referred to the resistance 7 as hav- Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the. scope of the appended claims without departmg from the spirit and scope of my invention.
Having thus described my invention, what claim is:
1. In combination, a source of electric current the voltage of which rises above its nor- 5 mal value when on open circuit for a considerable period of time, an electric lamp, a normally open circuit including said source and said lamp, a slow acting thermostatic circuit controller having a winding included in said circuit, and means controlled by'said circuit controller for preventing the supply of excessive current to said lamp when the circuit becomes closed and for subsequently reducing the resistance of the circuit.
2. In combination, a source of electric current the voltage of which rises above its normal value when on open circuit for a considerable period oftime, an electric lamp, a normally open circuit including said source so and said lamp, a thermostat included in said circuit, and means controlled by said thermostat for permitting the supply of normal current but preventing the sup ly of excessive current to said lamp after tlie circuit becomes closed and while the voltage of said source is dropping to its normal value.
3. In combination, a source of electric current the voltage of which rises above its normal value when on open circuit for a considerable period of time, an electric lamp, a
thermostat having a winding and a normally closed contact and a normally open contact, a normally open circuitincluding said source and said lamp as well as said nor- 85 mally closed thermostat contact and a resistance, and an auxiliary circuit including said source and said lamp as well as the normally open contact of said thermostat but excluding said resistance.
4o 4. In combination, a source of electric current the voltage of which rises above its normal value when on open circuit for a con siderable period of time, an electric lamp, a normally open circuit including said source and said lamp, a thermostat having a winding included in said circuit, and means controlled by said thermostat for reducing the resistance of said circuit after the circuit has been closed long enough to allow the voltage of said source to drop to its normal va ue.
In testimonywhereof I afiix m si ature.
AR W. F IS R.