US2291947A

US2291947A - Regulation of arc lamps

Info

Publication number: US2291947A
Application number: US325271A
Authority: US
Inventors: Buchwald Arno
Original assignee: KISLYN CORP
Current assignee: KISLYN Corp
Priority date: 1939-02-17
Filing date: 1940-03-21
Publication date: 1942-08-04
Anticipated expiration: 1959-08-04

Description

1942' A. BUCHWALD 2,291,947

REGULATION OF ARC LAMPS Filed March 21, 1940 IN V EN TOR.

Patented Aug. 4, 1942 REGULATION OF ARC LAMPS Arno Buchwald, Berlin-Haselhorst, Germany, as-

signor t0 Kislyn Corp-oration, New York, N. Y., a corporation of Delaware Application March 21, 1940, Serial No. 325,271 In Germany February 17, 1939 2 Claims.

This invention relates to the regulation of arc lamps.

It is known to compensate for the consumption of arc lamp electrodes with the aid of an adjusting device which advances the electrodes in accordance with the arc lamp current and/ or the arc lamp voltage. To this end, relays have been employed which control a particular auxiliary device, for instance, which switch in and out a motor.

When regulating arc lamps in such a manner by means of a relay it has proved particularly disadvantageous in that the magnitude determining the position of relay changes immediately after initiating the control motion, whereupon the relay is immediately operated again. The advantage of this regulation consists therefore in the fact that the consumption of the electrodes is compensated for when being advanced at very short intervals, whereas the regulating device or the relay is very often operated. In this manner an extremely rapid wear and tear is caused. It is true that also connections are known in which the feed of the electrodes is influenced by a relay consisting of a magnet and armature. If the armature is attracted upon the energization of the magnet, a considerable reduction of the magnetism is necessary in order to bring it back again into its original position. From the original position the armature returns to its operating position upon a further considerable increase of the magnetic flux. Such control devices are, however, far too insensitive and cannot be sufficiently adjusted. To remove the above drawbacks are lamps are regulated according to the invention with the aid of a relay in such a manner that a control motion caused by the relay is suppressed if owing to the changed values of current and/or voltage the relay releases another control motion as a result of the changed position of the relay. It is particularly advantageous to employ a circuit closed by the relay and to maintain the circuit with the aid of an auxiliary device if the relay itself has already again opened the contact.

Only when operating another relay contact, the automatic holding device of the first circuit is brought out of operation so that this circuit is replaced thus eliminating the regulating effect caused by the same.

A relay which may be satisfactorily used in connection with this invention is illustrated and described in detail in my copending application Serial No. 325,270 filed March 21, 1940.

Further details of the invention will be apparent from the description of an embodiment of the regulating arrangement according to the invention in connection with the accompanying drawing.

An arc lamp has its electrodes energized from any suitable current source as shown and is provided with two electric motors for feeding the electrodes with the aid of suitable intermediate means. The negative electrode is influenced by the motor I, whereas the positive electrode is regulated by the motor 2. The speed of the driving motors may be controlled by potentiometers 3 and t respectively, energized by a power source (not shown) through terminals 5 and 6. This source of power for the driving motors may be the same source as that for operating the arc, but obviously can be an entirely independent source of the same or diiierent voltage. The circuit extends from the terminal 5 through the change-over switch 1 on the one hand through the potentiometer 3 to the terminal 6 and on the other hand through the potentiometer 4 to the terminal 6. Between this terminal and the movable contacts of the potentiometer the driving motors l and 2 are connected through the change-over switches 8, 9 and [0, in Which case the speed of the motors may be varied by adjusting the potentiometer contacts allotted thereto. The switches l, 8, 9 and H] are connected by a common actuating member in such a manner that either the just-described circuit is rendered possible which causes the motors for feeding the electrodes to operate continuously or that the switches operate an automatic control device by the position shown in the drawing.

The connection so far described need not take into consideration the errors as regards the proper distance between the electrodes caused by a non-uniform consumption of the electrodes and by fluctuations of the operating voltage. For this purpose, a control system is provided cooperating with a relay, which system may cooperate with the regulating arrangement so far described and arranged in the arc lamp together with Contact pairs Hi to Hi. In this automatic regulating arrangement is provided a contact system B designed, for instance, in the form of a moving coil relay and whose reed I2 is influenced by the magnetic field of the coil l3 which receives its current through the contact pair H3, H4 from the shunt 14 arranged in the main circuit of the arc lamp to be regulated. The magnetic field produced by the coil i3 is therefore proportional to the arc lamp current so that the position of the reed I2 of the relay R is controlled in accordance with the arc lamp current.

The reed I2 of the relay R plays between contacts I5, I6, I1 and I8, of which the contacts I6 and I1 come directly into engagement with the reed I2, whereas the contacts I and I6 are only closed by the contacts I6 and I! designed as trailing contacts. Upon a movement of the current traversed reed I2, for instance, in a direction towards the contact I6, the latter is first closed; i. e., the connection between I2 and I6 is established and upon a further deflection of the reed I2 also the contact I5 comes into engagement so that the connection between I2, I6 and I5 is established. In the same manner the contact I! and also the contact I8 are closed upon the movement of the reed I2 in the other direction.

The reed I2 is connected through the fuse I9 and the contact pair Hz to the change-over switch I, which in the position shown-switching in the automatic regulating deviceestablishes a direct connection with the terminal 5 connected to the power source. The contacts I5, I6, I1 and I8 are, however, connected through the coils of auxiliary relays 20, 2| and 22 and through the protective resistor 23 by means of the contact pair II 9 to the terminal 6 connected to the power source.

The coil I3 of the relay R is so connected to the shunt I4 lying in the circuit of the arc lamp that upon a decreasing current the reed I2 of the relay R moves in a direction towards the contact I6 and closes the latter if the arc lamp current attains a given difierential below the desired value. chosen as 1% of the desired value by correspondingly adjusting the spring carrying the contact I6. The contact I 6 closes then the circuit through coil of the auxiliary relay 2| to which the switches 2 I and 2 I are allotted. The switch 2| is parallel connected to the contact between the reed I2 and the contact I6 so that the circuit is maintained not only through this contact but also through the switch 2| of the auxiliary relay 2|. The switch 2|" also operated by the auxiliary relay 2| closes the circuit extending from the terminal 5 through the change-over switch I, the contact pair Hz, the fuse I9, the switch 2|", the change-over switch 24, the contact pair H5 and the switch 8 to the driving motor I of the negative electrode and then through the change-over switch 9, the contact pair 6, the change-over switch 25, the regulable resistor 26 and the contact-pair ||9 to the terminal 6. The motor I will therefore move the negative electrode towards the positive electrode with the speed regulable by the resistor 26, thus increasing again the current flowing through the arc lamp. Upon this increase of current, the relay coil I3 is impressed through the shunt I4 with an increased voltage so that the reed I2 of the relay R comes out of engagement with the contact I6. Upon this interruption the flow of current through the auxiliary relay 2| is, however, not interrupted, since the switch 2| operated by the coil of the relay 2| continues to maintain the circuit. The value of the resistor 26 is chosen in such a manner that the speed of the motor I corresponds substantially to the normal consumption of the electrodes or is somewhat higher. In this case the reed of the relay I2 may be moved within certain limits by the variable arc lamp current without varying the adjusted rate of feed of the relative electrodes so that a smooth operation or This differential may be burning of the arc lamp is ensured without the need of permanently efiecting a subsequent regulation.

If the arc lamp current becomes greater than the desired value, for instance, by the fact that the negative electrode has been advanced too rapidly, the contact I! is closed. The current flowing through the relay R flows now no longer through the switch 2| and the coil of the auxiliary relay 2| which always offers a certain resistance, but through the reed I2 and the contact I! to the protective resistor 23, the purpose of this resistor being to prevent an unduly high current from flowing through the reed I2 of the relay R. Because of this short circuit current ceases to flow through the coil of the auxiliary relay 2| and the switches 2| and 2| open. While the switch 2| disconnects only the coil of the relay 2| from the power source, the switch 2 I interrupts the current flowing through the motor I so that the drive comes to rest and the negative electrode is no longer advanced. The latter consumes gradually and increases the are so that the arc lamp current returns again to its desired value. In this manner the relay reed I2 coming out of engagement with the contact |'I interrupts the short circuit of the relay 2|, without releasing any further control operation. Only after the arc lamp current has been further reduced the reed I2 comes into engagement with the contact I6, closes therefore the circuit for the auxiliary relay 2| and puts the motor I again into operation through the switch 2|. The play of the contacts is repeated in the manner described above so that the arc lamp current is kept within the range determined by the distance of the contacts I6 and H from the reed I2. By changing the distance of the contacts from the reed I2 it is thus possible to adjust any accurate regulations and number of regulations.

It may happen that the arc lamp current attains a value below the value allotted to the contact I6, for instance, is reduced by 10%. This will always be the case if the arc lamp is not yet in operation but the voltage is applied to the terminals 5 and 6 and the electrodes are still apart. When the current falls considerably below a given value the reed I2 of the relay R will close the contact I5 through the trailing contact I6 and also energize the coil of the auxiliary relay 20 besides the coil of the auxiliary relay 2| already energized by the contact I6. This relay 20 operates not only the switch 26 which supplies energy to the relay 20 independently of the position of the relay reed I2 but also the switch 20" which short circuits the resistor 26. The motor I of the negative electrode is therefore supplied with a particularly strong current through the switch 2| also closed by the auxiliary relay 2| and through the change-over switches 24 and 25; i. e., it moves the negative electrode at a considerably higher speed towards the positive electrode than is the case if only the auxiliary relay 2| is energized and the resistor 26 is effective in the circuit. The auxiliary relay 20 actuates therefore a device which brings about a rapid movement, thus igniting with the lamp in operation the arc lamp or increasing the arc lamp current within a very short period.

The switch 2|)" will, however, not be open again if the relay reed I2 releases the contact I5 through the contact I6, since the coil of relay 20 is continuously energized through the switch 20'. Also when the contact I6 comes out of engage ment with the contact reed I2 the motor I running at a high speed will not yet be disconnected, since the switch 2| supplies current also to the coil of relay 2| independently of the position of the reed I2. Only when the desired value of the arc lamp current is exceeded even by a slight amount and the contact I1 is closed the auxiliary relay armatures firmly held by the coils of relays 2|] and 2I drop, since these coils are short circuited through the contact I'I. Upon the armatures being released the switches 20', 20", 2| and 2I are opened; i. e., the motor I comes to rest. The adjustment of the arc lamp current to the desired value is effected therefore very rapidly also upon a considerable drop below a given value of the arc lamp current without, causin the contacts of the regulating arrangement to oscillate permanently.

It may happen that the arc lamp current exceeds the desired value by a considerable amount, for instance, if the electrodes come into engagement upon the ignition of the arc lamp. In this case the reed I2 of the relay R will not only close the contact II but also the contact I8, whereby current is supplied to the coil of an auxiliary relay 22, whose armature closes the switch 22' and brings furthermore the switches 24 and 25 into the switch position not shown in the drawing. A circuit is then closed extending from the terminal 5 through the switch I, contact pair I I2, fuse I9, switch 25, contact pair Ila, switch 9 to the driving motor I and then through switch 8, contact pair II5, switch 24 and contact pair H9 back to the terminal 6. However, since the motor I is traversed by current in the opposite direction, the motor runs backwards at a high speed provided that the field excitation remains constant and moves the electrodes apart until the reed I2 of the relay R leaves the contact I'I. At this moment the current flowing through the coil of the auxiliary relay 22 and maintained constant by the switch 22 independently of the position of the contact I8 is interrupted so that also the switches 24 and 25 return to the position of rest shown; i. e., deenergize the motor I. The negative electrode of the arc lamp is, consequently, moved--when the desired arc lamp current is exceeded by a considerable value-back a distance at a great speed, which is to be maintained under the prevailing operating conditions. Also in this case the regulation of the electrode is effected independently of the engagement of the contact I8 by the switch 22' so that the regulation initiated at a great speed is effected up to the desired value of the current.

In the embodiment shown the arc lamp current flowing through the shunt I4 influences through the relay R and motor I only the position of the negative electrode, whereas the position of the positive electrode is not influenced. However, in order to keep the positive electrode in the proper position with respect to the mirror, for instance, when using the arc lamp for cinema projectors or searchlights a thermal switch 2! may be provided which, for instance, is closed if an image of the are or of the positive electrode projected by a known device is projected in the case of a false position of the anode close to the thermal or heat sensitive member. Current then flows from the terminal 5 through the switch I, the contact pair I I2, the fuse I9, the contact pair II1, the switch 21, the contact pair He and the coil of the auxiliary relay 28 through the contact pair IIg back to the terminal 6, so that the armature of the auxiliary relay 28 short circuits through the switch 29 a regulable resistor 30 which is arranged in the circuit of the feed motor 2 allotted to the positive electrode. While in normal operation the motor 2 by suitably adjusting the resistor 30 advances the positive electrode in accordance with the normal consumption, the resistor 39 is disconnected with the aid of the thermal switch 21 during the consumption of this electrode and therefore an accelerated feed of the same is brought about. The speeds of the motors are chosen in such a manner that only relatively slow movements are imparted to the electrode, whereas the motor I imparts a relatively high speed to the negative electrode when using the rapid or backward movement. When the arc lamp is in operation the positive electrode will therefore maintain practically its position, whereas the negative electrode is at first approached with the aid of the device for a rapid movement and is then rapidly moved backwards with the aid of the device for the backward movement to form an arc.

What is claimed is:

1. In a control system for regulating the adjustment of the electrodes of an arc lamp having electrically operated means for adjusting at least one of its electrodes, a main relay in circuit with the electrodes, an auxiliary relay operable by said main relay, a circuit controlled by the auxiliary relay connecting the electrode adjusting means to a source of electrical energy, a holding circuit established by the operation of the auxiliary relay to maintain the circuit to the electrode adjusting means, and means controlled by main relay acting only in response to variations of predetermined magnitude in the operating characteristics of the arc lamp to release said holding circuit thereby interrupting the circuit to the electrode adjusting means.

2. In a control system for regulating the adjustment of the electrodes of an arc lamp having electrically operated means for adjusting at least one of its electrodes, a main relay in circuit with the electrodes, an auxiliary relay operable by said main relay, a circuit controlled by the auxiliary relay connecting the electrode adjusting means to a source of electrical energy, a holding circuit established when the auxiliary relay operates to close the electrode adjusting circuit, said holding circuit locking the auxiliary relay in position to maintain the circuit to the electrode adjusting means, and mean controlled by main relay acting only in response to variations of a predetermined magnitude in the operating characteristics of the'arc lamp to short circuit said holding circuit thereby releasing the auxiliary relay to permit it to interrupt the circuit to the electrode adjusting means.

ARNO BUCHWALD.