US2305096A - Automatic circuit controller for gaseous discharge devices - Google Patents

Description

1942- J. A. MODERMOTT 2,305,096

AUTOMATIC CIRCUIT CONTROLLER FOR GASEOUS DISCHARGE DEVICES Filed June 19, 1941 Fig"; 45 5 42 1 M M Julian Amuermow, INVENTOR.

ATTORNEY.

Patented Dec. 15, 1942 AUTOMATIC CIRCUIT CONTROLLER FOR GASEOUS DISCHARGE DEVICES Julian A. McDermott, Elmhurst, Long Island,

Application June 19, 1941, Serial No. 398,738

13 Claims.

The invention here disclosed relates to the control of circuits for gaseous discharge devices. The objects of the invention are to protect such circuits and apparatus forming parts of the circuit from the sudden voltage rises which normally result from such causes as the removal of a tube or the failure of a tube in the secondary circuit and to prevent damage or electric shocks of dangerous duration or intensity that might result from contact with or grounding of the high tension wiring system and to continue such protection during all normal operating conditions.

In furtherance of such protection, it is an ob- Ject of the invention to effect automatic opening of the primary circuit of the transformer upon the occurrence of abnormal conditions in the secondary circuit and to maintain the primary circuit open until the power supply is cut off and to repeatedly effect automatic opening of the primary circuit until such time as the abnormal condition in the secondary circuit is corrected.

The foregoing and other desirable objects are attained by novel features of construction, combinations and relations of parts all as hereinafter set forth, illustrated by way of example in the accompanying drawing and broadly covered in the claims.

Figs. 1, 2, 3 and 4 are wiring diagrams illustrating four difierent embodiments of the invention.

Fig. 5 is a broken sectional detail of a special air gap construction which may be used with and form part of the invention.

In the first embodiment of the invention illustrated, gaseous tubes 1 and 8, are shown connected across the secondary winding 9, of a transformer suited to the purpose.

At some intermediate point H), of the secondary, a connection II, is made to one side of a relay magnet [2, the other side of which is grounded at IS.

The armature l4, normally cooperates with a contact IE, to close circuit through the primary winding l6, of the transformer.

One side of the primary circuit is shown as grounded at H, and some form of control switch is provided in the primary circuit, such as represented at l8.

In the event of abnormal conditions in the secondary circuit, such as might result from removal or breaking of one or both of the tubes, causing an arc to ground at 22. or by a direct grounding of the secondary circuit as by physical contact with some part of the secondary circuit,

a surge of secondary current will extend from point 10 through connection H and relay I2, to ground at l3, causing the magnet to lift armature ll, thus to interrupt the primary circuit at l5, and, by engagement with the upper contact l9, to put line voltage through the coil, by way of armature I, connected with one side 20, of the line and contact l9, through the coil to ground and, by way of the ground l1, to the other side 2|, of the line. This provides the action of a double throw, self -holding relay, which first takes secondary current to open the primary circuit and then holds the primary circuit open by line voltage through an energizing circuit which it closes at l9, at the time it opens the primary circuit at l5.

After the protective relay has operated as described to open and hold the primary circuit open, the main switch l8, can be opened to deenergize relay l2, and permit the primary circuit to again close at I4, ii. If the grounded condition in the secondary has been corrected. then the main circuit can be closed at I0, and the armature M, will remain in engagement with contact ii. If however, the abnormal secondary condition still exists and grounded current still can flow through the relay when primary switch 9 is closed, thenthe relay will repeat its protective function, continuing to act in this way until the fault in th. secondary has been cured.

It is intended that the minimum current required to actuate the relay shall be less than that of human resistance to shock, that is, less than the so-called let go" current.

To protect the equipment against abnormally high voltages, an arc gap or gaps 22, 22, of proper design and proportions may be connected in the high voltage circuit of the secondary. These are shown connected at opposite sides of the secondary winding and may be of diiferent values or dimensions to prevent a balanced condition.

As a substitute for or even in conjunction with the arc gaps 22, 22, are operated contactors or so-called automatic cutouts 23, 24, which automatically close when an arc occurs across a gap,

may be connected either across the individual tubes 1 and 8, or, as indicated in the second instance, as at 24, in series with a spare tube 25, for one of the tubes 8.

In Fig. 1, the failure of'tube 1, would then cause the contactor 23, to complete the circuit, due to the are that would result, and if the tube 8 failed, the arc in contactor 2|, would cause the lighting of tube 25.

The high vcltage'protective feature of the arc gaps would be present in the are operated cutouts 23, 24, but using these, the rate of operation of s48 relay should be slower than that of these cutouts, or the gaps may be so dimensioned as to cause the parts to cooperatively function as described. Commonly used means for retarding the action of relays may be employed.

In general, the connection at II. for tripping the relay may be taken from any point or either end of the secondary winding.

If desired, an arc gap may be put in the relay circuit to ground, as in connections Ii, running from the secondary tap it, to the relay coil. particularly where it might be desirable to have a direct ground connection to the transformer secondary.

Fig. 2 illustrates a modification in which the holding circuit for the relay is accomplished without grounding the primary circuit.

In this case, the relay is provided with an additional winding 28, connected at 21, with the holding contact IS. The other side of this separate winding is connected at 28, with one side 2|, of the line.

The operation is similar to that first described. Abnormal conditions in the secondary will occasion a flow of current through the relay magnet l2, which, as it picks up its armature H, interrupts at 15, the primary circuit to the transformer and closes circuit at I9, 21, from one. side 20, of the line through the holding winding 28, and connection 28, to other side 2|, of the line. The relay will then hold the primary circuit open until conditions have been restored to normal in the secondary circuit, such protection being afforded in this instance, without depending upon a grounding of the primary circuit.

Fig. 3 illustrates a modification or a simplification of the invention, in which an abnormal voltage in the secondary produces an are at 29, or 30, through a common connection 3 I, to the relay magnet l2, and ground at IS.

The armature of the magnet is sustained in this instance, by a spring pressed trigger 32, pivoted at 33, and which can be tripped by push button 34, to restore the primary circuit at l5, after conditions have been corrected in the secondary. In this particular form of the invention, the secondary tap may be ground as indicated at 35.

Under certain conditions, it may be desirable to connect the relay between high tension points of the transformer circuit through a. gap or gaps.

Such an arrangement is shown in Fig. 4, where the relay winding is shown connected through arc gaps 36, 31, across the ends of the transformer secondary.

In this particular illustration, upon energization of the relay, the armature I4, releases a, spring tensioned contactor 38, to interrupt the primary circuit at 39, which then remains open until abnormal conditions in the secondary have been corrected and the contactor is returned. as by operation of a restoring button 40.

Thermal relays employing windings and bimetallic contact strips may be substituted for the magnetic elements indicated. The action of such relays however, might be slower as so constructed and the protective value thus lessened. The contacts employed may be of the mercury capillary type, if current conditions warrant.

By connecting the primaries in multiple and by interconnecting the transformer grounding connections, it is possible to use one relay of the types described to protect a number of transformer systems.

To make the relays operate properly and reduce sparking, condensers and or resistors that will 2 nswer under the special circumstances, may be employed. Time controlled relays of the numerous types available may be used.

Various size arc gaps may be required, depending upon transformer voltages.

One form of are gap particularly suited to the invention is illustrated in Fig. 5. This comprises a metallic shell 4|, which may be ventilated as indicated at 42, and which has insulated high tension terminals 43, II, at opposite ends of the same. Insulating bushings II, II, in opposite ends of the sleeve support the terminals and also carry, in insulating cement 40, N, the electrodes 41, 41, dimensioned and spaced from the metal shell to determine the discharge voltages. The shell may be supported in a suitable mounting and grounding clamp. The structure shown provides double arc gaps. but if only one are gap were desired, only a single spaced insulated electrode would be provided within the shell.

The invention provides an effective control and protection for gaseous discharge devices, applicable at low cost to new or to existing systems and providing full protection to apparatus and to those installing or servicing such systems.

What is claimed is:

1. In control apparatus, the combination of a transformer for gaseous discharge tubes, a relay connected between a point on the transformer secondary and ground, contact means actuated by said relay to open the primary circuit of the transformer and means for effecting the holding of said contact means in said open primary circuit position until abnormal conditions in the secondary circuit which occasioned energizing of the relay have been corrected.

2. In control apparatus, the combination of a transformer for gaseous discharge tubes, a relay connected between a point on the transformer secondary and ground, contact means actuated by said relay to open the primary circuit of the transformer, means for effecting the holding of said contact means in said open primary circuit position until abnormal conditions in the Secondary circuit which occasioned energizing of the relay have been corrected, said last means including holding connections for the relay .established in the primary circuit of the transformer when said relay is first energized.

3. In control apparatus, the combination of a transformer for gaseous discharge tubes, a relay connected between a point on the transformer secondary and ground, contact means actuated by said relay to open the primary circuit of the transformer, means for efi'ecting the holding of said contact means in said open primary circuit position until abnormal conditions in the secondary circuit which occasioned energizing of the relay have been corrected, said last means including an additional holding winding in the relay and connections for establishing current flow through said holding winding when said relay is first energized.

4. In control apparatus, the combination of a transformer for gaseous discharge tubes, a relay connected between a point on the transformer secondary and ground, contact means actuated by said relay to open the primary circuit of the transformer, means for effecting the holding of said contact means in said open primary circuit position until abnormal conditions in the secondary circuit (which occasioned energizing of the relay have been corrected, said last means including a manually releasable trigger for mechanically retaining the contact means.

5. In control apparatus, the combination of a transformer for gaseous discharge tubes, a relay connected between a point on the transformer secondary and ground, contact means actuated by said relay to open the primary circuit of the transformer, means for effecting the holding of said contact means in said open primary circuit position until abnormal conditions in the secondary circuit which occasioned energizing of the relay have been corrected, said last means including a trip operated by the relay, said con-.

tact means being of the self-opening type and normally held closed by said trip and means for manually restoring said contact means and trip to the circuit closed condition 6. In control apparatus, the combination of a transformer for'gaseous discharge tubes, a relay connected between a point on the tr nsformer secondary and ground, contact mean actuated by said relay to open the primary cir uit of the transformer, means for effecting the holding of said contact means in said open primary circuit position until abnormal conditions in the secondary circuit which occasioned energizing of the relay have been corrected and arc gap control means associated with said secondary circuit.

'1. In control apparatus, the combination of a transformer for gaseous discharge tubes, a relay connected between a point on the transformer secondary and ground, contact means actuated by said relay to open the primary circuit of the transformer, means for effecting the holding of said contact means in said open primary circuit position until abnormal conditions in the secondary circuit which occasioned energizing of the relay have been corrected, the secondary of the transformer being connected to groundv through an arc gap.

8. In combination, a transformer for gaseous discharge devices and a relay connected to be energized from the secondary of the transformer through an arc gap to ground from over-voltage v in the transformer secondary and connected to open the transformer primary when so energized. 9. A controller for gaseous discharge devices,

comprising in combination with a transformer ated by said relay. 5

10. In a controller for gaseous discharge devices a transformer having substantially constant/current characteristics, a relay connected between the secondary winding of the transformer and ground, said relay having a winding for carrying the transformer secondary current and :a reluctance sufficient to permit operation of the relay from line voltage and contact means controlled by said relay to interrupt the primary circuit of the transformer and to connect said relay winding to line voltage.

11. In control apparatus, the combination of a transformer for gaseous discharge tubes, a

relay connected between a point on the transformer secondary and ground, contact means actuated by said relay to open the primary circuit of the transformer, means for effecting the holding of said contact means in said open primary circuit position until abnormal conditions in the secondary circuit [which occasioned energizing of the relay have been corrected, the secondary of the transformer being connected to ground at a point removed from the point of connection of the secondary with the relay through an arc gap.

12. In combination with a transformer for gaseous dischargetubes, the secondary of said transformer being connected to ground through an arc gap, a relay operable by secondary circuit current and connected between a point on said transformer secondary and ground, contact means operable by said relay to effect opening of the primary circuit of the transformer, means for effecting the retention of said contact means in said open primary circuit condition and a manually operable control switch in series relation with said contact means.

13. In combination .with a transformer for gaseous discharge tubes, the secondary of said transformer being connected to ground through an arc gap, a relay operable by secondary circuit current and connected between a point on said transformer secondary and ground, contact means operable by said relay to effect opening of the primary circuit of the transformer, means for effecting the retention of said contact means in said open primary circuit condition, a manually operable control switch in series relation with said contact means, said retention means including holding connections in the primary circuit adapted to be completed by operation of said relay.

JULIAN A. MCDERMO'I'I.

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