US2769136A - Relays for constant current regulators - Google Patents

Description

W. C. WOOLEY RELAYS FOR CONSTANT CURRENT REGULATORS Filed Sept. 4, 1952 Oct. 30, 1956 INVENTOR.

WILLIAM C. WOOLEY B Y WW United States Patent RELAYS FOR CONSTANT CURRENT REGULATORS William C. Wooley, Ferguson, Mo., assignor to Moloney Electric Company, St. Louis, Mo., a corporation of Delaware Application September 4', 1952, Serial No. 307,781

6 Claims. (Cl. 323-6) It had been found prior to this invention that automatic constant current regulators of the moving coil type subject lamps of lighting circuits related to the automatic constant current regulators to current transients at the time the lamps are turned on. To put the lamps in service the normal procedure is to connect the series lighting circuit to the secondary of the regulator and energize the lighting circuit and the regulator simultaneously by closing the primary switch of the regulator. This subjects the low resistance of the cold lamp filaments of a lighting circuit to the maximum voltage of the regulator and the result is a current transient with a maximum value that is determined mainly by the minimum reactance of the regulator. The coils of the regulator move rapidly even though damped by oil, or in the case of a dry type unit by a dash pot, and the current is nearly constant by the time the lamp filaments arrive at normal operating temperature. However, even so, there seem to be some deteriorating effects on the lamp filaments which would not occur if the starting current transients were eliminated.

The prime purpose of this invention is to provide means for eliminating the current transients referred to above, and this is efficiently accomplished by incorporating in a lighting system, of which an automatic constant current regulator of the moving coil type forms a part, a relay which serves to short out the lamp circuit for a very short period (seconds at most) when the lamps are being turned on, so as to put the moving coils of the regulator in an open position, with resultant lowered voltage, before the lamp circuit is energized.

Fig. l is a diagrammatical view illustrating the moving coils of a constant current regulator in the closed, or maximum load position.

Fig. 2 is a diagrammatical view, similar to Fig. 1, but illustrating the moving coils of a constant current regulator in the open, or short circuit position.

Fig. 3 is a side elevation, with a part shown in section, of the improved relay of this invention.

Fig. 4 is a view partly in plan and partly in horizontal section taken on staggered line 44 of Fig. 3.

Fig. is an enlarged vertical section taken on line 5-5 of Fig. 3.

Fig. 6 is a wiring diagram of a typical lighting system which includes therein an automatic constant current regulator and a relay for shorting out the light circuit for a short time period immediately before the lamps are energized.

In the drawing, wherein is shown for purposes of illustration, merely, one embodiment of the invention, A designates in Figs. 3 and 4 the improved relay generally. The relay A comprises a base 1 formed of suitable electrical insulating material, and said base has secured thereto a laminated core 2 which is of substantially U-shaped construction, there being a lower, horizontal core portion 2a which is provided with opposed flanges 3 that receive suitable fastening devices 4 for securing ice the core to the base 1, an upstanding core portion 2b which is embraced by a coil 5 that is suitably supported in place, and a second core portion 2c which is provided at its upper end with opposed and spaced hinge portions 6. Hingedly secured to the hinge portions 6 of the core 2 is a laminated armature '7, such attachment of the armature to the hinge portions of the core being accomplished by extending a pivot pin 8 through openings formed through said hinge portions 6 of the core 2 and through extended portions 7 of the opposed outer laminations of the armature 7 (Fig. 4). By referring to Figs. 3 and 4 it will be noted that the top part of the portion 2b of the core extends upwardly slightly beyond the top face of the coil 5 and that a fastening strip 9 is employed to retain the coil'in place relative to the core. This fastening strip comprises a fiat strip of material having an opening 10 formed therein and a portion 11 of the core portion 2b extends through said opening 10, the top part of the core portion 2b being provided with a transverse groove 12 in which a portion 9 of the fastening strip 9 is seated, and corner portions 13 at the top of the core portion 2b being peened over into contact with the top face of the fastening strip so as to secure said fastening strip in close contact with the top face of the coil 5.

The armature 7 has secured thereto a bar 14 of electrical insulating material to which is fixed adjacent to the outer end thereof one of a pair of short circuiting contacts, the short circuiting contact which is supported by the bar 14 being designated by the reference character 15. The short circuiting contact 15 includes a downwardly extended shank 16 which is provided with a screwthreaded lower end portion that extends through an open ing 17 formed through the bar 14 (Fig. 5), said opening having an enlarged lower portion 17 which receives a washer 18 and a nut 19, the latter being screwed on the screwthreaded lower portion of the shank of the contact 15 and into tight contact with the washer 18 which is jambed against the top wall of the enlarged opening portion 17'. The short circuiting contact 15 is provided with a portion 15' which is of greater diameter than the shank 16 thereof and as a result an annular shoulder 20 is provided at the junction of the shank and the portion 15 of said contact between which shoulder and a top face portion of the bar 14 a washer 21 and a portion of a terminal 22 are interposed. From the foregoing it is obvious that the nut 19 securely retains the contact 15 in its proper position relative to the bar 14, and at the same time, said nut serves to firmly grip a portion of the terminal 22 so as to make good mechanical and electrical connection between the said contact 15 and said terminal.

Secured to the base 1 by a fastening device 23 is a bracket member 24 which includes a lower horizontal flange portion 241: through which the fastening device 23 extends, a vertically extended portion 24b and a horizontal, top portion 240, the lower and top portions being extended in opposite directions from opposite ends of the vertical portion 24b of the bracket member 24. The horizontal, top portion 246 of the bracket member 24 has an opening 25 formed therethrcugh and extended through this opening is the shank portion 26 of the second of the pair of short circuiting contacts previously referred to herein, said second short circuiting contact being designated by the reference character 27 and being adapted to move into and out of contact engagement relative to the first mentioned short circuiting contact 15. The shank portion 26 of the short circuiting contact 27 is embraced by a coil spring 28 whose upper end contacts with the lower face of the horizontal, top portion 246 of the bracket member 24 and Whose lower end contacts with the top face of the contact 27, said coil spring tending to urge said contact 27 in a downward direction. Also, the upper end portion of the shank portion 26 of short circuiting contact 27 is screwthreaded, and screwthreadedly mounted on said upper screwthreaded portion of said shank portion is a pair of nuts 29 and 30 with which is associated a washer 31, an extension 32' of a terminal 32 being interposed and tightly clamped between the washer 31 and the nut 29, so as to provide secure mechanical and good electrical connection between the terminal 32 and the short circuiting contact 27.

Secured to the base 1 of the relay A by means of suitable fastening means 33 is the housing 34 of a dash pot 35, said housing having disposed therein a plunger 36. The plunger is supported by a plunger rod 37 which is embraced by a coil spring 38, said coil spring contacting at its upper end with the under side of a head 39 that is fixedly mounted at the top of the plunger rod 37, and the lower end of said coil spring 38 contacting with the upper face of the top wall of the housing 34. As is shown to good advantage in Fig. 3, the dash pot 35 is so located in the relay structure that on downward movement of the bar 14 the head 39 of the plunger rod will be contacted by said bar so as to move the plunger 36 of the dash pot downwardly in the housing 34 thereof.

In the operation of a street lighting system provided with a relay for delaying flow of current to the lamps of a lamp circuit in accordance with the present invention, the series lamp circuit C is connected to the secondary of the automatic constant current regulator R, as is shown diagrammatically by Fig. 6, and when the automatic constant current regulator R is energized to put the lamp circuit C in service, the coils Ra of said regulator are in the relative positions in which they are shown in Fig. 1. Upon energization of the regulator R the operating coil of the relay A is energized and the core 2 of said relay is magnetized and this tends to pull the free end of the armature 7 and the outer end portion of the bar 14 downwardly to open the relay switches 15 and 27 by moving the contact 15 out of engagement with the contact 27. However, the head of the plunger rod of the dash pot 35 is engaged by the bar 14 and the operation of said dash pot delays downward movement of said bar and armature so that the contacts 15 and 27 may remain closed for the short period of time required for the coils Ra of the automatic constant current regulator R to move from the relative positions in which they are shown in Fig. l to the relative positions of said regulator coils Ra as shown in Fig. 2. It is pointed out that during the downward movement of the plunger 36 of the dash pot as a result of the force exerted by the bar 14 there is no immediate separation of the relay contacts 15 and 27, for the reason that the coil spring 28 moves the relay contact 27 downwardly in contact engagement with the relay contact 15 until the nut 29 contacts with the top face of the portion 240 of the bracket member 24, at which time the relay contact 15 which continues to move downwardly passes out of contact engagement with the relay contact so as to open said relay contacts 15 and 27 and permit current to flow to the lamp circuit C.

When the regulator R is energized, higher than normal current flows because at that time the voltage is highest and the impedance the least. This high current causes the regulator coils Ra to move apart rapidly to maximum separation and the position of minimum voltage. At this condition of minimum voltage the relay contacts open to cause the lamp circuit to be energized and the lamps lighted, and at this time the impedance of the lamp circuit is low and the secondary voltage is low. As the lamps are lighted the impedance of the lamp circuit increases and the coils Ra of the regulator R move closer together to raise the voltage, thus maintaining approximately normal current and causing the current frequency, and means for delaying passage of current from said regulator to said lamp circuit for a short period of time immediately upon energization of said regulator to place said lamp circuit in service, said delaying means comprising a relay including a core, a coil, an

armature, and pair of relay contacts one of which is movable with said armature from a closed position where the lamp circuit is short-circuited to an open position where said lamp circuit is energized, the other of said pair of relay contacts being adapted to move with its associated relay contact in contact therewith for a portion of the distance of movement of said one contact, and means for resisting movement of said armature, said means comprising a housing having a plunger movable therein which moves with said armature, and a member connected to said armature for actuating said plunger.

2. The combination of a street lighting lamp circuit, a movable coil type constant current regulator for maintaining normal rated lamp current on said lamp circuit under varying conditions of loading, primary voltage, and frequency, and means for delaying passage of current from said regulator to said lamp circuit for a short pe riod of time immediately upon energization of said regulator to place said lamp circuit in service, said delaying I means comprising a pair of relay contacts one of which is movable with said armature from a closed position where the lamp circuit is short-circuited to an open position where said lamp circuit is energized, the other of said relay contacts being spring pressed so as to move with its associated relay contact in contact therewith for a portion of the distance of movement of said associated contact means comprising a dash pot for resisting movement of said armature, and a member connected to said armature for actuating the plunger of said dash pot.

3. The combination of a street lighting lamp circuit, a movable coil type constant current regulator for maintaining normal rated lamp current on said lamp circuit under varying conditions of loading, primary voltage, and frequency, and means for delaying passage of current from said regulator to said lamp circuit for a short period of time immediately upon energization of said regulator to place said lamp circuit in service, said delaying means comprising a relay including a core, a coil, an armature, and pair of relay contacts one of which is movable with said armature from a closed position where the lamp circuit is short-circuited to an open position where said lamp circuit is energized, means including a dash pot for resisting movement of said armature, a member connected to said armature for actuating said dash pot means, for moving the second contact of said pair of relay contacts for a slight portion of the movement of the contact which is movable with said armature in contact therewith, and means for arresting said movement of said second contact.

4. The combination of a street lighting lamp circuit, a movable coil type constant current regulator for maintaining normal rated lamp current on said lamp circuit under varying conditions of loading, primary voltage, and frequency, and means for delaying passage of current from said regulator to said lamp circuit for a short period of time immediately upon energization of said regulator to place said lamp circuit in service, said delaying means comprising a relay including a core, a coil, an armature, and pair of relay contacts one of which is movable with said armature from a closed position where the lamp circuit is short-circuited to an open position where said lamp circuit is energizedmeans including a dash pot for 5. In a street lighting lamp circuit supplied With current from the secondary of a movable coil type constant current regulator for maintaining normal rated lamp current on said lamp circuit under varying conditions of loading, primary voltage and frequency, means for delaying passage of current from the secondary of said regulator to the lamps in said lamp circuit comprising a relay having a coil connected in the lamp circuit and a set of contacts connected to short circuit the lamp circuit When closed, said contacts being normally closed and opening in response to energization of said coil in the lamp circuit, and means for delaying the opening of said contacts upon energization of said coil.

6. In a street lighting lamp circuit as set forth in claim 5, said set of contacts comprising two movable contacts, one of said contacts being adapted to follow the other contact only for a portion of the opening movement of the other contact, said delaying means being operable upon said other contact to retard its opening movement upon energization of said coil.

Refiszrenees Cited in the file of this patent UNITED STATES PATENTS 792,091 Troy June 13, 1905 1,313,117 Sanborn Aug. 12, 1919 2,561,202 Houser July 17, 1951 FOREIGN PATENTS 14,295 Great Britain of 1902

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