US3246102A - Multiple-switch relay - Google Patents

Description

April 12, 1966 1.. B. RONK MULTIPLE-SWITCH RELAY 4 Sheets-Sheet l Filed March 26, 1964 FIG. I.

FIGZ.

April 12, 1966 L. B. RONK 3,246,102

MULTIPLE-SWITCH RELAY Filed March 26, 1964 4 Sheets-Sheet 2 United States Patent 3,246,162 MULTIPLE-SW11 CH RELAY Leroy B. Ronk, Nokomis, Ill., assignor to System Analyzer Corp, Nokcmis, llh, a corporation of Wisconsin Filed Mar. 26, 1264, Ser. No. 355,026 3 Claims. (Cl. 296-484) Among the several objects of the invention may be noted the provision of improved motor switching relay apparatus for soft starting of single-phase, capacitor-start, capacitor-run motors and the like; and the provision of conveniently operable gang-operated transfer switch means in apparatus which will handle high inductive reactive current or highcapacitive reactance current so that comparatively large motors may be accepted for use on single-phase lines to drive apparatus having low starting torque but requiring substantial running torque. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the mechan cal and electrical elements and combinations of such hiements, features of construction, and arrangements of parts and circuits which will be exemplified in the constructions hereinafter described, and the scope of which will be indicated in the following claims.

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated:

FIG. 1 is a basic wiring diagram illustrating, in a condition preliminary to starting, a motor switching circuit employing the invention;

FIG. 2 is a basic wiring diagram similar to FIG. 1, illustrating a running condition;

FIG. 3 is a side elevation of a transfer switch assembly shown in a position for making the FIG. 1 connections;

FIG. 4 is a plan view of FIG. 3;

FIG. 5 is an enlarged end view of a pant of the transfer switch assembly, the view being on line 5-5 of FIG. 3;

FIG. 6 is a rear view of FIG. 3 but showing a position for making the PEG. 2 connections;

FEG. 7 is a schematic layout of the structure shown in F165. 3-6 wherein the heavy lines indicate current fiow under starting conditions; and

FIG. 8 is a view similar to FIG. 7 wherein the heavy lines indicate current flow under running conditions.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

At present, utility companies make it a general rule to limit motor sizes acceptable on single-phase lines according to the amount of inrush starting current. This rule could have exceptions (not now allowed) if practicable switch gear were available to start motors driving certain classes of apparatus which, although having substantial running torque, have low starting torque. Moreover, there are a considerable number of motor applications to apparatus as above described having low starting torque requiring a comparatively small amount of starting current but which at running speed have a high running torque requiring high continuous running current. An example, but not the only one, is a fan drive which has a low starting torque (small current inrush) and a high running torque. The reason for this is that its load increases as the cube of the speed. By means of the present invention, a greater number of single-phase, ca-

pacitor-start, capacitor-run motors of considerably greater horsepower are made acceptable on single-phase utility lines for applications such as above described.

Referring now more particularly to FIG. 1, there is shown at numeral 1 the main winding of a single-phase capacitor-start, capacitor-run motor which also has a start winding 3. The main winding is connected across power leads L-l and L-2. A conventional starting switch (not shown) is employed in the leads L1 and L2 and the usual power circuit (also not shown), which for example may apply 220 v. The start winding 3, through leads 4 and 6 (and a conventional reversing switch, not shown) is adapted to be reversibly connected to the power leads L- i, L-Q. Connected in series with the start winding 3 is a capacitor 8 which is shunted by a second capacitor it series-connected with a conventional normally closed centrifugal starting switch 12. The centrifugal switch 12 opens when the motor gains a certain speed. Thus, as is conventional, during starting with switch 12 closed there is greater capacitance in series with coil 3 than under running conditions after the switch 12 opens.

The main winding is constructed in two sections 5 and '7, center-tapped as shown at 9. The center tap contains a first transfer switch A A second transfer switch A is in shunt connection with switch A and winding section 5. A third transfer switch A is in shunt connection with switch A and winding section 7. Shunt connected across the series-connected section 5 and switch A are a seriesconnected solenoid coil 23 and fourth transfer switch A It will be understood that the latter could as well be shunt-connected across the series-connected section 7 and switch A without changing the operation, as will appear. Shunt-connected around switch A; is a thermostatic or so-called warp switch 29 which is in heat-exchange relation with a resistance heater 31. The latter is in series connection with a resistance 35 and a fifbh transfer switch A these series-connected elements being connected across the leads L-d and L-2. Switch 29 closes upon being heated and is self-opening upon cooling. Switch 29 and the heater 31 constitute a time-delay device indicated by dotted lines and numbered -39. This time delay may be achieved by other than thermostatic means. As will be shown below, switches A A A A and A are gang-operated by a switching assembly such as shown in FIGS. 3-7.

Switches A A and A are of the heavy-duty type. Switches A A and 29 are in series with substantial resistances and are designed for lighter duty. Switches A and A are, in the present example, so-called micro switches. All of switches A A A A and A form parts of a switching assembly shown in FIGS. 3-7.

As shown in FIG. 1, switches A A and 12 are normally closed, and switches A A A and 29 are normally open when the motor is at rest. In FIG. 2, switches A 12 and A are open and switches A A and A are closed. This is the condition when the motor is running at full speed. Switch 29 is open, after having temporarily been closed when cold during motor acceleration (see the dotted-line position of switch 29 in FIG. 2 for the temporary closure).

Referring to FIG. 1, when the leads L-1, L-2 are excited, for example at 220 v. (motor shut down), this voltage is applied across the start winding 3 and the capacitors 8 and 10, the then cold centrifugal switch 12 being closed. This also applies 220 v. to the main winding 1. This voltage is divided between the two sections and 7, so that each operates at 110 v. This results in a so called soft start, meaning that the inrush of current through the series-connected sections 5 and 7 of run winding 1 is held at a low value during starting acceleration.

The 220 volts are also applied across the heater element 31, the series-connected resistance and the closed switch A The motor then accelerates in a direction depending upon how connections 4 and 6 are made across the leads L1, L-2 through the said conventional reversing switch. After a time the heater 31 causes switch 29 to close (see the dotted lines in FIG. 2). This excites solenoid coil 23 which, as will be shown below, by gang operation opens switches A and A and closes switches A A and A This is illustrated in FIG. 2, which shows that now each section 5 and 7 of the running winding 1 is individually connected directly across the leads L-1, L-2 and is subject to 220 v. This may occur before the motor has fully accelerated. This is the running condition wherein heavier current is drawn. At some time during acceleration, before or after switch 29 has functioned, the centrifugal switch 12 opens, so that the start winding 3 continues operation conventionally in series only with capacitor 8. When switch A is open as in FIG. 2, it cuts off current from the heater 31, which gradually cools, thus allowing the thermostatic switch 29 when cool to assume its normally open position (see the solid lines for switch 29 in both FIGS. 1 and 2). Switch 29 is then ready for a subsequent start after motor shut-down. Since the closing of switch A; maintains excitation of the solenoid coil 23, all of the gang-operated switches A A A A and A during running are held in the position shown in FIG. 2. Normally closed switch 12 is held in its open position during running by reason of the centrifugal action thereon at motor speed. When the line switch supplying leads L1, L-2 is opened, depriving leads L1, L-2 of voltage, all of the switches return to their normal positions shown in FIG. 1.

In view of the above, it will be seen that under the FIG. 1 starting conditions each section 5 and 7 of the run winding '1 has only 110 v. applied to it, meaning that a comparatively small amount of current is drawn. This is responsible for the so-called soft start. In the running condition of FIG. 2, each section 5 and 7 is impressed with 220 v., whereupon the required larger continuous load current is drawn.

In FIGS. 3-6, an advantageous transfer assembly is shown, this being an improvement upon the construction shown in my United States Patent 3,032,627. The transfer assembly comprises an insulating base 43 on which is mounted a laminated core piece 45 which has upstanding projections 47 and 49 outside of the coil 23. Coil 23 is hollow. Pivoted at 53 on the projection 49 is a rotatable laminated armature 55. This has an extending part 57 adapted when the coil 23 is excited to be drawn into the hollow interior portion 51 of the coil 23. The armature also has a forwardly projecting portion 59 for engagement with the projection 47 when the armature is drawn down (FIG. 6).

Affixed to the armature 55 is a heavy conductive (copper) contact bar 61 which moves as the armature moves and is thereby engageable and disengageable with a fixed contact 63. Return springs 65 bias the armature in a clockwise direction (FIG. 3). The biases together or closes contacts 61 and 63, which form switch A Spring 65 are anchored to the insulating base 43 at 71 and to the armature at 73. Upon excitation of the coil 23, the armature 55 is drawn down against the return action of springs 65, thus separating the contact 61 from 63, thereby opening switch A Contact 61 is in the form of a tailpiece extending from the armature. Contact 63 is bolted to and supported by an angle-shaped stationary conductor 67, supported on the insulating base 43. Conductor 67 carries a terminal 69.

On the top of the armature 55 is fastened an insulating crossbar 75 (see connecting bolts 77). At the op posite ends of the bar 75 are carried heavy-duty movable resiliently mounted or floating contacts 79 and 31, respectively. Since these are substantially of the same construction, description of one, i.e., '79, will suffice for both, numbering of subsidiary parts of each being the same. Each is L-shaped, having a short leg part 83 located on the front side of the insulating bar 75, and a long leg 85 located under the bar. A bolt 87, threaded through the short leg 83, serves to form a rocking support 89 extending loosely into a recess 91 in the bar 75. In the case of the contact 79, bolt 87 also serves as a fastener for a flexible conductor 95. The latter extends and is attached to the central movable contact 61 of switch A Passing loosely through a stepped opening 97 in the long leg 85 is a headed post 99. The post 99 extends through an opening in the bar 75 and is held against escape by a cotter key .101 which seats on a washer 103. A spring 105, which is seated in a socket 102 on the underside of the bar 75, presses against the long leg 85 of the contact to rock it in a clockwise direction. The headed post 99 prevents the contact 79 from downward escape and from being biased so far forward that the finger 89 could escape from pocket 91. In view of the above, it will be seen that the movable contacts 79 and 31 are held captive and are resiliently mounted on opposite ends of the bar 75.

Contact 79 is connected with terminal 76 by means of a flexible wire 107. Contact 81 is connected with terminal '78 by means of flexible wire 109. Each movable contact 79 is crimped as shown at 111 for rocking and wiping engagement with the sloping portion of a fixed contact. The fixed contacts are identical but the one eugageable by movable contact 79 is numbered 113, and the one engageable by movable contact 81 is numbered 115. Fixed contact 113 and movable contact 79 form switch A Fixed contact 115 and movable contact 81 form switch A The fixed contact 113 of switch A is carried on an L-shaped conductive bracket 1-17 attached to the base 43 and carrying a terminal 119. The fixed contact 115 of switch A is carried on an L-shaped conductive bracket 121 attached to the base 43 and carrying a terminal 123. Terminal 123 is connected by a wire 125 to terminal 69.

It will be understood that the L-shaped brackets 117 and 121 are identical, and that the fixed contacts 113 and 115 are also identical. As stated above, switches A A and A are of the heavy-duty variety, all of their contacts being composed of heavy copper bar stock. The movable contacts of switches A and A are carried on the insulating crossbar 75. Riveted to the top of the solenoid core 55 is an inverted channel piece 93 between which and the core is telescoped one end of the movable contact 61 of switch A Two screws 77, passing through the bar 75 and channel piece 93, are tapped into the telescoped part of contact 61 to hold it in place in connection with the solenoid core 55. This leaves the other end of the contact 61 as a movable tailpiece.

The mass of armature 55 and insulating cross-bar 75 imparts to it considerable inertia, which somewhat delays its starting motion from the FIG. 3 to the FIG. 6 position and also somewhat delays its reverse motion from the FIG. 6 to the FIG. 3 position. Thus in the first case the switch A will somewhat delay opening due to this inertial mass and the tension of the springs 105. Moreover, switches A and A will somewhat delay opening when the solenoid is deenergized, due to the inertial mass. This minimizes the usual noisy report such as would otherwise occur when interrupting reactive current. It will also be understood that switch A opens before switches A and A close, and that switches A and A ultimately reopen before switch A recloses.

Attached to the base 43 by means of a bracket 127 is a switch box 129 containing two snap switches. These consitiute the switches A and A Their terminals are numbered 141, 143 and 145. These are of the so-called micro variety and carry comparatively small currents because of the comparatively high resistance formed by the coil 23 (in the case of switch A and the resistances 31 and (in the case of switch A Further details in regard to these switches are unnecessary, since they are of a type known in the art. In the present case both switches A and A are operated from a single button 132 by a single lever 131, pivoted at 133 to the case 129. This single lever operates both switches simultaneously. In the position of the lever 131 shown in FIGS. 3 and 4 (biased by spring 135), switch A is in its normally open position and switch A is in its normally closed position, as indicated in FIGS. 1 and 5. When the armature is drawn down, as shown by FIG. 6, extension 57 strikes lever 13-1 to move it against bias of the spring 135, so as to close switch A; and open switch A as indicated in FIG. 2.

An advantage of the rotary armature 55 and of carrying the movable contacts of the switches A A and A on the armature, while supporting their contacts 63, 115 and 113 fixedly on the base 43, is that in one movement switch A, may conveniently be caused to open, and then switches A and A caused to close. This is accomplished by having the pivot point 53 of the armature so positioned (see FIG. 3) that, as the armature 55 moves counterclockwise, the movable contacts 79 and 81 descend and the movable contact 61 ascends. Moreover, the descent of the outer portion of the armature finally operates switches A and A Another advantageous feature is the symmetrical arrangement of the switches A A A A and A relative to the plane of movement of the armature (FIG. 6). Thus, by having switch A; in this plane and swtches A and A symmetrically flanking the plane in their positions on crossbar 75, together with the switches being symmetrically disposed relative to this plane and operated by the lever 131 in the plane, a balanced action is obtained. 'It should be noted that the positions of switches A A and A are in a symmetrical triangular relationship (FIG. 4).

FIGS. 7 and 8 are schematic views showing how the switch assembly of FIGS. 3-6 is interconnected with sections 5 and 7 of the motor winding 1. These views omit the start Winding 3 and its connections 8, 10 and 12. They include the time-delay device 39, which is constituted by a separately connecti-ble assembly. In these figures, flow of current through the switch assembly is indicated by the use of heavy lines under the start conditions in FIG. 7, and under the running conditions in FIG. 8.

As seen in FIGS. 7 and 8, motor winding section 5 is connected across terminals 76 and 78. Motor winding section 7 is connected across terminals 69 and 119. Lead L1 is connected to terminal 79. It is also connected to the solenoid coil 23 through terminals 137 and 138, to which are connected the coil lead wires 139. The other end of the coil is connected through its other terminal 137 to terminal 143 of switch A The other side of switch A, is connected to terminal 141. Terminal 119 is also wired to terminal 141. Terminal 141 also feeds one side of switch A The other side of switch A through terminal 145 is connected through heater 31 and resistance 35 with lead L-l. The thermostatic switch 29 is connected across terminals 141 and 143. As stated, the thermostatic switch 29 and its heater 31 and resistance 35 are not carried on the assembly shown in FIGS. 3-6.

In view of the above and as shown in FIGS. 7 and 8, it is apparent that the external connections for the switch assembly shown in FIGS. 3-6 can be conveniently made from the motor winding taps and the leads L-1 and L2. In addition, the thermostatic switch 29, heater 31 and resistance 35 may conveniently be connected, changed or replaced to suit conditions under which it is desired to switch over from the connections shown in FIG. 7 to those shown in FIG. 8. Thus FIG. 7 shows the switch arrangement under starting conditions in which the sections 5 and 7 operate in series at v. each. FIG. 8 shows the switch arrangement under running conditions, wherein the sections 5 and 7 operate in parallel at 220 v. Although a 220 v.-110 v. system has been described, it will be understood that the invention is equally useful on analogous system such as 440 v.-220 v.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions and circuits without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A multiple-switch relay comprising a base, an electromagnetic coil and pivot means on the base, an armature rotatable with respect to the base on said pivot means and cooperating with the coil with rocking movement in a plane passing through the coil, an insulating crossbar carried on the armature above the coil and extending transversely with its ends on two opposite sides of said plane, a first switch having a fixed contact located on the base on a third side of the coil and having a movable contact carried by the armature and extending in said plane toward said fixed contact, second and third switches having fixed contacts located on opposite sides of the coil respectively and transversely of said plane, said second and third switches having resiliently mounted movable contacts carried adjacent the ends of said crossbar for cooperation with their fixed contacts respectively, dual switch means on the fourth side of the coil opposite the location of said fixed contact of the first switch, means on the armature for operating said dual switch means, said pivot means being located to provide a rotary movement of the armature and said insulating bar carried thereby such that upon excitation of the coil the movable contact of the first switch rises from its fixed contact and thereafter the resiliently mounted movable contacts of the second and third switches descend resiliently on their fixed contacts, and said dual switch means is operated by descent of the armature.

2. A multiple-switch relay comprising a base, an upright electromagnetic coil and transverse pivot means on the base, an armature rotatable with respect to the base on said transverse pivot means and movable into and out of the coil with rocking movement in a plane passing lengthwise through the coil, an insulating crossbar carried on the armature and extending transversely with its ends on two opposite sides of said plane, a first switch having a fixed contact located on the base on a third side of the coil in said plane and having a movable contact carried by the armature and movable in said plane to and from said fixed contact, second and third switches having fixed contacts located on said two opposite sides of the coil, said second and third switches having resiliently movable contacts hinged adjacent the ends of said crossbar, the movable contacts of the second and third switches being symmetrically disposed in a triangular relationship to the movable contact of the first switch, the fixed contacts of the second and third switches being symmetrically disposed in a triangular relationship to the fixed contact of the first switch, normally open and normally closed dual switch means on the fourth of the coil opposite the location of said fixed contact of the first switch, common control means for simultaneously operating the dual switches, drive means on the armature opposite the fixed contact of said first switch for operating said dual switch control means, said pivot means being located to provide a rotary movement of the armature and said insulating bar carried thereby such that upon excitation of the coil the arma- I s 8 ture is pulled down into it and the movable contact of the Refezences Cited by the Examiner first switch rises from its fixed contact and thereafter UNITED STATES PATENTS the movable contacts of the second and third switches A descend resiliently upon their fixed contacts, and said 1,736,391 8/1929 Goff 200107 dual switch means is operated by descend of said drive 5 2,735,968 2/1956 Boghle et a1 200 87 X means located on the armature 3,115,561 12/1963 Lewis et al 20()87 3. A relay made according to claim 2, wherein the movable contacts of the second and third switches are resil- BERNARD GILHEANY Examiner iently mounted on said insulated crossbar. R. N. ENVALL, JR., Assistant Examiner.

Claims (1)

1. A MULTIPLE-SWITCH RELAY COMPRISING A BASE, AN ELECTROMAGNETIC COIL AND PIVOT MEANS ON THE BASE, AN ARMATURE ROTATABLE WITH RESPECT TO THE BASE ON SAID PIVOT MEANS AND COOPERATING WITH THE COIL WITH ROCKING MOVEMENT IN A PLANE PASSING THROUGH THE COIL, AN INSULATING CROSSBAR CARRIED ON THE ARMATURE ABOVE THE COIL AND EXTENDING TRANSVERSELY WITH ITS ENDS ON TWO OPPOSITE SIDES OF SAID PLANE, A FIRST SWITCH HAVING A FIXED CONTACT LOCATED ON THE BASE ON A THIRD SIDE OF THE COIL AND HAVING A MOVABLE CONTACT CARRIED BY THE ARMATURE AND EXTENDING IN SAID PLANE TOWARD SAID FIXED CONTACT, SECOND AND THIRD SWITCHES HAVING FIXED CONTACTS LOCATED ON OPPOSITE SIDES OF THE COIL RESPECTIVELY AND TRANSVERSELY OF SAID PLANE, SAID SECOND AND THIRD SWITCHES HAVING RESILIENTLY MOUNTED MOVABLE CONTACTS CARRIED ADJACENT THE ENDS OF SAID CROSSBAR FOR COOPERATION WITH THEIR FIXED CONTACTS RESPECTIVELY, DUAL

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