US2008514A - Starting apparatus for electric discharge lamps and the like - Google Patents

Description

July'l6, 1935. J. PETERSON 2,008,514 I STARTING APPARATUS FOR ELECTRIC DISCHARGE LAMPS AND THE LIKE Filed Feb. 28, 1934 1110M RESISTANCE Z0 mam/m; 30

Ihvenior: Justin Peterson,

Patent ed July 16, 1935 PATENT OFFICE STARTING APPARATUS FOR ELECTRIC DIS- CHARGELAMPS AND THE LIKE Justin Peterson, Saugus, Mass., assig'nor to General Electric Company, a corporation of New York Application February 28, 1934, Serial No. 713,404 s claims. (01.1'16-124) My invention relates to apparatus for starting electric discharge lamps and more particularly to apparatus for starting sodium vapor discharge lamps.

One object of my invention is to provide a starting apparatus whereby a current substantially below normal operating current is applied at high voltage to the lamp simultaneously with the energization of" the cathode filament andwhich will be changed to normal operating current and voltage after a predetermined interval of time subsequent to each energization of the cathode filament.

Another object of my invention is to provide such a starting apparatus for operation through a complete cycle after each current interruption.

For a better understanding of my invention,

together with other and further objects thereof, reference is had to the following description, taken in connection with the accompanying drawing, and its scope will'be pointed out in the appended claims. The accompanying drawing illustrates diagrammatically an electric discharge lamp and starting apparatus therefor built in accordance with my invention. a

The discharge lamp is of a known type comprising a glass envelope containing a gas, such as neon, and a metal, such as sodium, for example. Current flowing between electrodes, also contained in the glass envelope, ionizes the gas and the metal which is vaporized and thereby gener ates light.

Referring to the drawing in detail, I. is a discharge lamp, for example a sodium vapor lamp, provided with anodes 2 and 3 and cathodes 4 and 5. The lamp is energized through a transformer whose primary winding 1 is connected to a,source 8. A condenser 9 connected across the source 8 and a high frequency choke coil l connected in series with the primary winding 1, absorb high frequency currents and thereby tend to eliminate interference of this lamp with radio reception in its immediate vicinity. A secondary winding II is connected directly to the filamentary cathode 4 by conductors l2 and I3. Asecondary winding I4 is connected to filamentary cathode 5- through conductors l5, l6 and Il. An operating winding l3 and a high resistance starting winding l9 are 50 connected in series with each other by conductors 20 and 2| and to the anodes 2 and 3 through coning and starting windings l8 and IS. The current flow at this time is, however, maintained far below the normal operating current value by making the high voltage starting winding l9 a high resistance winding. This small current is sufllcient to partially ionize the gas in the lamp so that when thecathodes have reached their operating temperature and the starting winding is shunted, the current supplied by the operating winding i8 at normal operating voltage is sufllcient to energize the lamp to full brilliancy.

For the purpose of shunting the starting winding Hi, I provide a switch comprising a pair of contacts 22 and 23 mounted respectively on contact arms 24 and 25. ,These contacts are operstarting winding l9 th ough a conductor 2|. The. contact arm 25 is connected to the other side of I the starting winding through conductor 26, relay coil 21, conductor 28 and conductor It.

When no current flows through the primary winding I, the contacts 22 and 23 are separated and the shunt circuit) about the starting winding is broken. As soon as current flows. in the winding I, a circuit is established through the cam operating motor. This circuit may be traced from-the winding 1 through conductors 30 and 3|, contacts 32 of the relay 21, which is not then energized and therefore closed, conductor 33, cam operating motor 34, conductors 35 and 36 to the other side of the primary winding. The motor 34 being thereby energized operates, through its shaft 38,'a pair of cams 39 and 40. The cam 39 controls the operation of the contacts 22'and 23 while the cam 40 controls the operation of a relay 4| which also controls the contactst22and 23.

The cam 50 is provided with a notch 42 which registers with the end of a contact arm 43 shortly after the motor 34 is energized, the cam being turned clockwise. The contact arm 43 then moves into the notch and thereby closes a circuit through the coil 44 of the relay 4|. This circuit may be traced from one side of the primary winding 1 through conductor 30 to contact arm 46, contacts 41 and 48, contact arm 43, con-- ductor 49, relay coil 44 and conductor 36-to the other side of the winding. This energizes the relay coil 44 and causes it to attract its pivoted armature 5| which engages the end of contact arm 24 and tends to move it'so that contact 22 will engage contact 23. The contact arm 24 is provided with a projection 52, however, whichengages the cam surface 33 and can only be moved when a notch 53 in the cam 33 is opposite the winding 1 the motor 34 turns the cams clock-' wise and as just explained establishes a circuit to the relay coil 44. The cam 39 moves simultaneously so that notch '53 does not register with the projection 52 and consequently the armature It simply draws the arm 24 inward so that the projection 52 will ride on the cain surface. Si-

multaneously the armature 5i operates a contact member 58 so that it establishes a locking circuit for the coil 44 in shunt to the contacts 41 and 48. This is necessary since as the cam 40 continues to rotate, the arm 43 rides out oi the notch 42 and again opens the circuit through the contacts. The locking circuit maintains thecoil 44 energized as long as current flows in the primary winding I. This locking circuit may be traced from conductor 30 to conductor 3|, con- -tacts 31, I8 and 53 to conductor 49. The motor continues to operate until it .has made a complete revolution and the notch 53 isoppositeto the projection 52. 'The relaycoil 44 being still energized, draws the contact arm inwarduntil the contacts 22 and 23 engage. This energizes the relay coil 21 which opens its contacts 32 and thereby deenergizes the motor 34. This position or the contacts then continues until the current to primary winding 1 is interrupted. When the current is interrupted the contacts resume their respective position as shown in the drawing and upon reenergization oi the winding 1 the d scribed cycle oi! operation is repeated. 1

For obtaining the necessary timing between the energization of the cathodes and the shunting starting voltage plus the normal operating voltage is applied across the anode and cathode. The high resistance of the starting winding is prevents a large current ilow and therefore injury to the cathodes by bombardment. A small current flowing, however, helps to ionize the gases and vapors within the tube so that by the time the filaments have attained the proper temperature the lamp is in condition to start operating under normal voltage and current. As exa,oos,s 14

plained above, the operating motor 34 revolves the cam 38 through a complete revolution in approximately seconds whereby through the cam and switch arrangement a shunt circuit is established across the starting winding I! at the end of that period. Simultaneously, the relay coil 21 is energized and opens its contacts, thereby deenergizing the motor 34 and stopping the cam. As long as current flows the motor remains deenergized and the relay armature 5|, which established a locking circuit for its coil 43 through its contact 56, will hold the shunt circuit closed. If current is interrupted relay 21 closes and the contacts 22 and 23 are separated, since coil 43 is also deenergized. The'apparatus is then in condition to repeat its cycle of operation. v

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

1. In a starting apparatus for an electric discharge device provided with a cathode and an anode, the combination of means for energizing said cathode, means for applying normal operating voltage and supplying normal operating current to said device. means for applying a starting voltage and for limiting the current flow to a value substantially below normal simultaneously with the energization oi said cathode, and means for shunting said last-mentioned means a predetermined interval oi! time subsequent to the energization of said cathode.

2. In a starting apparatus for discharge de vices provided with an anode and a cathode, the combination of means for energizing said cathode, means for applying normal operating voltage and current to said device, means connected in series with said means ior increasing the voltage across the anode to cathode and for limiting the current flow to a-value substantially below normal operating current. and means for shunt ing said last-mentioned means a predetermined time interval subsequent to each energization' of said cathode.

3'. In a starting apparatus for discharge lamps provided with an anode and a cathode, the combination of means for energizing said cathode, means for supplying normal operating current at normal operating voltage, and means connected therewith for increasing said operating voltage and for limiting the current flow to substantially below normal simultaneously with the energization of said cathode, and meansg for shunting said last means a predetermined jtime interval subsequent to each energizatioi'lr'oi said cathode comprising a synchronous motor operated switch, a relay energized simultaneously with the ener gization or said cathode, said relay tending to close said switch for shunting said high voltage means and a cam operated by said synchronous motor for preventing the closure of said switch until a predetermined interval of time subsequent to the energization of said cathode.

- JUSTIN PETERSON.

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