US 2249994 A
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Description (OCR text may contain errors)
July 22, 1941. Q wARRlcK 2,249,994
RELAY DEVICE Filed May 18, 1958 IN VENTOR.
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Patented July 22, 1 41 RELAY DEVICE Charles Fredericks Warrick, Detroit, Micln, assignor of one-half to Imperial Brass Manufacturing 00., Chicago, 111., a corporation of ,Illinois Application May 1a, 1938, Serial No. 208,728
My invention relates to electrical controls and particularly magnetic actuated controls suitable for use in a variety of installations. Among the objects of my invention is to provide a new and improved electric control which is positive acting and sufficiently powerful so that movable parts therein of rugged construction can be shifted by a simplified circuit arrangement.
Another object is the provision of a new and improved electric control for an apparatus wherein the circuit operating the controlling portion of the device is insulated from the line circuit.
Another object is the provision of an electromagnetic control device for an electric apparatus which is so constructed that when a sudden additional demand is made on the line circuit due to a change of conditions within the apparatus the power operating the control device is temporarily varied to compensate for unbalanced conditions iii the apparatus in order that the control portions of the device may function properly at all times.
Still another object is the provision of an electromagnetic control device responsive to changes in liquid level in a container which is operatively connected to auxiliary attachments in such a manner that as the level of the liquid changes in the containenthe auxiliary attachments are set in operation or released therefrom, depending upon the particular liquid level conditions at which the device is adjusted to operate without the use of floats.
A further object is the provision of a new and improved liquid level control which is operable by meansof electrodes suspended in the liquid in order to control operations of a pump suitable for changing the level oi the liquid in response to the operations of said device.
With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my device whereby the objects contemplated are attained as hereinafter more fully set forth and pointed out in my claims and illustrated in the accompanying drawing in which:
in such a manner that they can be supplied with I a current strong enough to do the work desired without that current being so great as to jeopardize the safety of any person coming in ,contact therewith. By providing a positive acting relay of this character the construction can be kept extremely simple so that an electrician with no more than a fundamental grounding in his art is capable of making adjustments and repairs without it being necessary to send the entire instrumerit back to the factory. The extremely simple control elements and a pump controlled thereby,
positioned in a sump.
Figure 2 is a diagram of a transformer used in v construction of my device also permits it to be built quickly and cheaply without sacrificing any fineness of adjustment in its operation and insures a product which can be sold to the public at a price commensurate with its usefulness.
By the use of electrodes as herein set forth, the control device is readily operable in a conductive liquid in containers under pressure since no mechanical connection other than an insulated electric wire is needed between inside and outside of the container, a condition not true of floats. Moreover the device is operable even though a sheet of ice forms on the surface of a conductive liquid such as water for example, when immersed in the conductive liquid underneath.
My device in general consists of a transformer, or in some instances a condenser, having the primary side directly and permanently connected to a source of alternating current. The secondary side of the transformer includes a circuit necessarily insulated from the primary circuit and operable to actuate a magnetic relay, the armature of which is pivoted so that when actuated it is capable of throwing a heavy switch or other similar functions requiring movement of an actuator arm with considerable force.
In the embodiment of my invention shown in Figure 1, the electrical control device A is shown within the dotted line connected to a motor M which is set up so as to drive a sump pump P located at the bottom of the sump S. The electric control device includes a transformer Ill having a primary side II which is connected by line wires l2 to a source of alternating current. The secondary side I3 01' the transformer has one connection H to a ground which may be at the point I! in the sump or elsewhere connected to the ground. Another connection l6 from the secondary coil leads to a magnetic relay I1.
The relay I 1 includes a core member l8, one pole portion IQ of which is wound with a coil of wire 20 connected to the secondary'circuit wire l6. An armature 2| is provided mounted upon an extension 22 pivotally supported at a point 23.
The extension is adapted to Jointly operate a pair of switches 24 and 2!, the detailed operation of which will be presently described.
Switch 24 which for illustrative purposes may be called the relay switch has a pair of terminal points 26 and 21. The point 28 is connected by means of a lead 28 to an end of the relay coil opposite from the end connected with wire I! leading to the transformer secondary coil. The same point 28 is likewise connected through a lead 29 to an electrode 3| which is suspended in the sump at an upper level. The other terminal point 21 is connected by means of a lead 3i directly to an electrode I2 which is suspended in the sump at a level lower than the electrode 20.
The switch carried by the extension which for descriptive purposes will be termed the motor switch, includes a contact arm I2 adapted to close the circuit between terminal points N and 35. A wire 26 from the point 25 is connected with one of the line wires i 2 while a wire 21 connects the other terminal point 24 to the pump. A parallel wire It connects the pump directly with the other of the line wires l2 thereby connecting the pump into the same circuit which supplies the transformer in. A description of the operation ioilows:
As has been noted the transformer ill at its primary side is permanently connected to a source of alternating current which thereby tends to continuously set up a current in the secondary cell which may be a step down in voltage as indicated in Figure l by any proportionate ratio, or if desired in some instances a step up ratio may be used. One of the terminals of the secondary coil is permanently connected with a ground.
When using the control for controlling the water level in a sump a change in level L of the liquid contained in the sump is utilized for actuating the electric control device. To accomplish this the electrodes 20 and 32 as previously noted are suspended at different levels in the sump. Assuming that it is the purpose of the invention to draw water from the sump so that the level is lowered the electrode 22 is suspended well down in the sump. Since as a practical matter it is preferred not to have the motor start and stop too often, the second electrode 30 is suspended at a relatively high level in the sump in order that the interval between the two may represent a considerable quantity of liquid. As the liquid level rises in the sump contact is first made with the lower electrode 32, but since the relay switch 24 is open there is no change in the condition of the circuit even though there is a potential short circuit between the ground I! and the electrode 32. As the level continues to rise the liquid eventually comes into contact with the electrode 30. At this point a contact is made which completes the circuit through the transformer secondary coil and simultaneously the relay coil defined by the wires 29, 28, l8, l3 and ii. The relay coil thus excited sets up a magnetic field which draws the armature 28 downward thereby closing both the relay switch and the motor switch. It is to be noted that since the magnetic flux around the armature is felt only when the secondary circuit is closed there can be no flux induced therein by continuous excitation of the primary side of the transformer.
When the motor switch closes the motor is started and the pump acts to draw liquid from the sump into the intake apertures of the pump and thence drives it upward through an outlet pipe II to a suitable sewer or drain. As the liquid level is lowered it breaks contact with the electrode Iii but since it remains in contact with the electrode 32 the circuit through the relay coil and transformer secondary remain: closed, thereby continuing to excite the magnetic field produced by the relay coil holding the armature in place and holding the motor switch closed. Eventually the liquid level will be lowered to a point out of contact with the lower electrode 32 thereby breaking the circuit through the relay coil and transformer secondary. With the circuit thus broken the armature 2| will be released and will be sprung. upwards opening both switches thereby shutting off operation of the pump and at the same time resetting the relay switch 24 to its initial position ready for a succeeding operation. By this arrangement the pump is never dry thereby increasing its efficiency of operation. Moreover, the frequency of its operation will be determined by the quantity of water contained in the sump between the electrodes 30 and 22 which under normal drainage conditions will mean that the motor and pump by operating only occasionally has a greatly increased life.
On occasions when the electric control device is used with apparatus in the nature of a motor and pump such as is shown in Figure l, the initial starting torque of the motor might be so great as to temporarily lower the line current. If this lowering were sumciently great as it might be at the end of a line the induced current in the secondary coil of the transformer might be low enough so as to prevent or at least render more inefficient the operation of the relay coil, a condition which might fail to properly lower the armature and close the switches. To obviate this, one of the wires 38 connecting the pump with the line circuit 12 may be wound around the primary side of a transformer ll in the form of a coil 42. In a transformer wound in this manner when an apparatus such as a motor reduces the line current operative upon the primary coil H of the transformer the coil 43, acting as a step up coil, adds to the magnetic flux on the primary side, thereby inducing a greater current in the secondary coil I! to compensate for the temporary reduction. Therefore the current in the secondary circuit remains great enough to actuate the relay and promote eflicient operation thereof. a
A modified type of device is shown in Figure 2, wherein the series coil has been omitted. In this device line wires i2 supply current to the primary coil ll wound on the transformer core iii. A secondary coil II has leads l4 and I6 from it to a relay mechanism similar to that described in connection with Figure 1. Wires 28' and I! may be directly connected to a motor circuit.
Some changes may be made in the construction and arrangement of my device without departing from the real spirit and purpose of my invention and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may be reasonto control operation of the apparatus, said aux-- iliary coil being operable upon a change in the power load due to a change in operating conditions in said apparatus to temporarily vary the current supplied to said relay in order to counter-balance the change in the transformer resulting from a variable demand by the apparatus.
2. In an electric control device comprising a transformer including a magnetic core having a primary winding permanently connected toa continuous source of alternating current, an electric apparatus subject to control by said device connected to said source of current, a step-up coil on the primary side of said transformer connected in series with, said apparatus, a secondary coil in said transformer continuously excited by the primary coil and a relay comprising a separate stationary magnetic core and a coil of wire thereon actuable by said secondary coil to start operation of the apparatus, said step-up coil being operable upon an increase in the power load due to the starting of said apparatus to temporarily increase the current supplied to said relay in order to counter-balance the loss in the transformer resulting from an increased starting demand by the apparatus.
3. In a liquid level control device including a container for liquid, a pump and an electric motor for driving said pump having connections to a continuous source of alternating current,
the combination of an electric control for the motor operable by the liquid comprising a'transformer having a closed magnetic core adapted to have the primary side permanently connected to said continuous source of alternating current for continuously exciting an alternating current in a secondary coil, a ground connection for one a secondary winding on another side subject to a continually induced current from the primary side having one end thereof connected with the ground, a relay member having a stationary core forming, a portion of an intermittently closed -magnetic circuit independent of said first magnetic circuit including a pivoted armature forming when pivoted to one position another portion of the second closed magnetic circuit, a winding on the stationary portion of said relay core having one end connected to the other end of the secondary winding, a holding circuit connected to the other end of said relay. winding including a pair of spaced electrodes, a switch having two contact points connected one to each of said electrodes respectively, an external conductor adapted to initially connect both electrodes with said one end of the secondary circuit operable a'fter disconnection from one electrode to maintain a closed secondary circuit until the other of said electrodes becomes disconnected container for liquid, a pump and an electric moto! for driving said pump having connections to a continuous source of alternating current, the combination of an electric control for the motor operable by the liquid comprising a transformer having a core comprising a closed magnetic circuit having the primary coil permanently connected to said continuous source of alternating current and a secondary coil, a ground connection for one end of the secondary coil, a relay device including a 'core comprising a separate magnetic circuit bearing a coil of wire having one endconnected to another end of the secondary coil and an armature having a motor switch for controlling actuation of the motor, a-
end of the secondary coil, a relay device comprising a separate intermittently closed magnetic core bearing a coil of wire having one end connected to another end of the secondary coil and an armature having a motor switch for controlling actuation of the motor, a holding circuit connected to the other end of the relay coil including a holding switch actuated by said armature and a pair of electrodes connected respectively with opposite holding switch points and suspended independently in the container at differ-'- ent levels, the upper of said electrodes being directly connected with the secondary transformer coil through the relay and operable when-contacted by. the liquid to complete the circuit through the'relay causing actuation thereof to operate the switches, the lower of said electrodes 7 being operable to maintain the'relay circuit closed holding circuit connected to the other end of the relay coil including a holding switch actuated by said armature and a pair of electrodes connected respectively to opposite holding switch points and suspended independently in the container at different levels, the upper of said electrodes being directly connected with the secondary transformer coil through the relay and operable-when contacted by the liquid to complete thecircuit through the relay energizing said relay and causing actuation of the armature to operate the switches, the lower of said electrodes being operable to maintain the relay circuit closed after the liquid level recedes below the upper electrode until the liquid breaks the electric connection with the lower of said electrodes, and an intermediate coil surrounding the primary side of the transformer connected in series with one of the motor terminals operable on initial starting of the motor when the motor circuit is closed to modify the electric output of the transformer resulting from the'sudden additional load imposed by the motor on the source of electric current.
CHARLES FREDERICKS WARRICK.