US1993057A - Electric control system - Google Patents

Description

March 1935. A. E. HAFF ELECTRIC CONTROL SYSTEM Filed Feb. 10, E 1952 INVENTOR, QrfrZ/zur E Huff,

" ATTOR-NEY.

Patented Mar. 5, 1935 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to improvements in electric circuits. An object of the invention is to provide electric circuits with interposed time elements for closing a circuit or circuits to any desired translating device or devices, as an electric motor in a controlled circuit that is connected to the supply line, or to separate independent circuits.

Broadly, my invention comprises a system of circuits incorporating a single instrument, as a thermostat, for initially introducing current into the system and putting it in operation, together with means for automatically maintaining, within a predetermined time after the instrument opens the circuit, an uninterrupted circuit within the system itself and the controlled circuit or circuits, and means for automatically opening and closing another circuit, or circuits, connected to the current supply wires and operating electric motors, or devices of plus and minus characteristics in this controlled circuit, as demanded by the instrument. It is designed that the instrument carry a minimum current for initially supplying current to a motor for the purpose of starting the same before, and, after the motor is connected to the line wires. With a small current through the controlling instrument, a minimum arcing will necessarily occur at the contact points, thus insuring their long life. The instrument may be installed where the vibration is severe. The controlled mechanism is designed to be operated only while the instrument, as a thermostat, is in contact to close the circuit to the motor, and within a limited time after the instrument breaks contact. It can be used with instruments having either a single or dual contact. An extremely close regulation, as will be described, is also permitted with my'circuit arrangement. Also; both plus and minus mechanisms are inoperative when the control instrument is in its neutral or intermediate position, as will be fully described.

Referring to the drawing:

Fig. 1 is a diagrammatic view showing two electric controlling pieces of apparatus of identical construction in their inoperative positions, with the control instrument in a neutral position.

Fig. 2 shows a modification of the system with a double piece of apparatus illustrated; both parts of the system are identical.

'1 and 2 indicate the line wires or source of electrical energy; 3 and 4, electric motors or other source of motion to which the disc members 5 and 6 are secured in any suitable way and are driven by the motors. 7 indicates removable wedgeshape pins that may be adjustably located in the series of openings or recesses 8, suitably spaced,

of the disc members. 9 indicates an instrument, as a thermostat, for closing the circuit to either one of the motors, as the motor 3, shown 5 in dotted lines, through the contact 10, wire 11, and return wires 12 and 13 to the other side of the line wires. 14 is a wire from the line 2 to the contacts 15 which will be opened when the arm 16 engages one of the removable wedge- 10 shaped pins 7, but normally is closed when this arm is positioned between two of the pins 7 of the disc 5. Connected to the spring contact arm 16 are wires 17, 18 and 19, the wire 18 being connected to the coil 20 of the double pole relay is 21 having the two movable contacts 23 and 24. The relay coil 20 is connected by the wires 25 and 13 to the line wire 1. The wire 19 is electrically connected to the movable contact 24. The other movable contact 23 is electrically connected by 20 the wire 26 to the line wire 1. 27 indicates a wire connected to wire 11 and contact 28, and 29 is a wire connecting the contact 30 and one terminal of the motor 31 or other piece of apparatus to be controlled; 32 being the return wire of this motor 25 or other translating device, as an electric bulb, heating coil or circulating fan, for example: 33. indicates a second multipole relay having its enerigizing coil 34 connected in parallel with the wires 19 and 25 by means of the wires 37 and 38. 30 39 is a series of movable contacts connected to the several motors, indicated at 40, and to the line wires 1 and 2, as shown.

The operation of this left hand portion of my circuit controlling device may be described as follows:

Assuming the instrument 9 closes with the contact 10, the line current sets the motor 3 in motion from line wire 2, instrument 9, contact 10 through wire 11, motor 3, wire 12 and wire 13 40 back to line 1. This permits contacts 15 and 16 to close by the action of the revolving disc, allowing current to flow to the relay coil 20 from line 2 through wire 14, contacts 15 and 16, wires 17 and 18, relay coil 20, wires 25 and 13 back to line 5 1. Following the energizing of relay coil 20, contacts 28 and 24, 30 and 23 are closed. Contacts 2 1 and 28 permit current to flow from line 2 through wire 14 contacts 15 and 16, wires 17 and 18. contacts 24 and 28, wire 27 to wire 11, thereby bridging the instrument 9 in the event that it is still closed, or feeding all of the current required by motors and relay coil 20, until contacts 15 and 16 are open and contacts 9 and 10 are open. At the same time, relay armature contacts 28 and 24 are closed, contacts 30 and 23 close permitting current to flow to the controlled pieces of apparatus 31 from line 1 through wire 26, relay armature, contacts 30 and 23, wire 29, motor 31, wire 32 to line 2. This is a controlled circuit. Coil 33 of the relay 34 is a supplementary relay of the multipolar type, whose coil is energized at the same time that relay coil 20 is energized. This supplementary relay 34 is connected in parallel with relay 20 through wire 37, relay coil 33, wires 38 and 13. At the same time that controlled motor 31 is put in operation, current from the line wire 2, wire 32, motors 40, movable contacts 39, wires 41 and 26 set the several motors or other devices in operation, when these contacts 39 en gage the contacts 42, thus completing the circuit through the wires 43 and 44.

When the instrument 9 closes the circuit at 10, part of the current on the instrument side of the line is divided, part passing through the motor 3 by wire 11 and part through the contacts 15 and 16 by wires 14, 17 and 18 to the relay coil 20.

When the contact 10 is open, the entire system will open or come to rest when a pin 7 opens the contacts 15 and 16. It will start again when the instrument closes the circuit to the motor 3, as

already described. Also, the position of the pins 7 permits extremely close regulation. In this way, the controlled circuits having the motors 31 and 40, or any other translating piece of apparatus are very accurately timed as to their operation. 1 It is to be understood that the dual circuit shownon the right hand of Fig. 1 is operated and controlled in the same manner as that already described. The single instrument 9 serves to operate both sets of circuits, one for plus and the other for minus controlled machines or devices.

Referring now to the construction shown in Fig. 2, in which a resistance 45 is inserted between the wires 11 and 27. When the thermostat 9 closes the circuit to the motor 3, some current will flow to the relay winding 46 through the wires 11, resistance 45, wire 27 and coil 46. This current will not be sufficient to pull up or move the armature of the relay 4'7. As soon as the motor 3 starts, a pin '7 will allow the contacts 15 to close. This allows a full voltage current to flow to the winding 46 of the relay 47 through the wire 27, whereby the armature of 47 will be pulled up to close the contact 48 and allow current to flow to the motor 40 through the wires 49 and 50. As the disc revolves and another pin 7 opens the contacts 15, the current will still flow through the thermostat 9, if closed, causing the motor 40 to run and allowing suflicient current through the resistance 45 to hold the relay armature 46' up. When the contacts 9 open, the motor 3 continues to run with current fed from line 2, contacts 15 and 16, wire 27, resistance 45, motor 3 back to line 1, until another pin 7 opens the contacts 15 and 16, which causes the motor 3 to come to a standstill, stopping the motor 40. When the thermostate 9 is in an intermediate position, no'part of the system or controlled apparatus is in operation.

It will, therefore, be seen that with my arrangements of circuits with the opening or closing of the contacts or 10 of either set of circuits, at very close regulation of the controlled devices is accomplished for any desired purpose, for example: maintaining the temperature of a room constant when the motors 31 or 40 or other translating devices on the left side are utilized as a source of heat, and the motors 31 or 49 or other translating devices on the right side are utilized as a source of refrigeration, either the heater or refrigerating machine will operate as the thermostat demands. The heaters and refrigerating units may be placed within the room or within a circulating ventilating system supplying conditioned air to the room. It may also be utilized for controlling the humidity of a room by sub stituting a humidistat for the temperature controlling thermostat 9. The motors 31 and 40 would then operate any desired apparatus for supplying to or withdrawing moisture from a room such as a testing laboratory where the moisture content of the air within the room is critical. It is to be understood that the wires 26 and 29 in Fig. l are utilized, either to close the circuit from some external source of electrical energy, (not shown), or are connected to the same source or lines 1 and 2, as shown in the diagram. In other words, the, wires 26 and 29 are the controlling part of the circuit that is being controlled through the contacts 23 and 30.

One pole of the relay operates to bridge the thermostat 9 and supply current to the motors 3 and 4, until the thermostat will open and contacts are opened by a pin "7. It is also understood that relay 21 may have as many poles as is necessary for the controlled circuit. That is, it may contain four poles, three of which would control a device on a three phase system and one pole utilized for bridging the instrument, as described before.

Fig. 2 is a modification of the control system shown in Fig. 1.

The multipolar relays 33 are also to be considered controlled circuits. 33 shown, any suitable device may be substituted.

In Fig. 2, the resistances 45 are understood as being balancing resistances.

As the time of travel between the adjustable pins 7 on the rotating disc 8 can be accurately adjusted, the controlled apparatus can be very closely regulated for controlling the controlled circuits in which the motors 31 and 40 are connected; it being understood that these motors represent any desired piece of apparatus to be operated, as a fan or refrigerating unit. Also, since the single control instrument serves the dual purpose of stopping and starting either motor 3 or 4, the system is especially adapted for closely regulating the moisture content or temperature in a room. In other words, my invention is a dual control system that automatically operates within a very small difference in condition such as a slight change in temperature or relative humidity.

' It will be noticed that a supplemental circuit to the motors 3 and 4 on the instrument side of the main, wires is made as follows: wire- 14, contacts 15 and 16, wires 17 and 19, armature 24, contact 28 and wires 27 and 11. This circuit materially reduces current carried by the instrument, reduces sparking at contacts 10 and 10' and prevents chatter to the relay 21 and controlled circuits.

What I claim is:

1. An electric control system having in combination with current supply mains, an electric motor, an automatically operating and circuit controlling device interposed between the current supply mains and the motor for opening and closing the circuit to the motor, a multiple pole relay, circuit connections between the winding of the relay and the current supply mains, means operable by the motor for opening and closing the circuit to the coil winding of the said In place of the relays relay, contacts operated by the said relay, circuit connections from one of the poles of the said relay, operated contacts to the windings of the motor and to the two sides of the current supply means, a translating device electrically connected to another contact of the relay operated contacts and having connection with the supply mains.

2. In combination with current supply mains, an electric motor, an automatically operating and circuit controlling device interposed. between the current supply mains and the motor for opening and closing the circuit to the motor, a multiple relay, circuit connections between the said relay winding and the current supply mains, adjustable means operable by the motor for opening and closing the circuit connections to the windings of the said relay, a plurality of contacts operated by the relay, a translating device electrically connected to one or the said relay operated contacts and having connections with the current supply mains, a second contact operated by the said relay, electrical ccnnec between the second contact, the windings of motor, a core of the multiple ralay and th current supply means.

3. In an electric control system, a source oi". electrical energy, an electric motor, electrical 7 connections between the source and the motor,

an automatically operating device in the connec-- tions for opening and closing the connection whena predetermined atmospheric condition takes place, as a definite temperature, a multiple pole relay, connections between the windings of the relay and the source, a make and break contact device in the relay windings of the ccnnections and operated by the motor, a connection from one relay operated contact to the motor including the source of electrical energy and a circuit through a core to the said relay-operated contact and the motor circuit, and means operated by the motor for varying the time or" closure of the make and break contact in the relay windings.

l. In an electric. control system, a motor, a source of electrical energy, electrical connections between the source and the motor, an automatically operating device in the connections, for alternately opening and closing the connections to the motor, a multiple pole relay, a circuit connection from a contact of the relay to the motor, independent connections between the windings of the relay and the source of electrical energy, make and break contact devices in the relay windin connections and operated by the said motor, and adjustable means operated by the motor for effecting a predetermined time of closure of the make and break contacts in the relay windings, said means comprising a member operated by the motor and adjustable devices in the member which operate the said make and break devices.

5. In an electrically operated control system, a source or" electric energy, an electric motor connected to the source of electric energy, a single automatically operating device interposed in the motor connections for setting the motor in motion, a controllable circuit in the control system, a current translating member in the controllable circuit, r ovable predetermined time means operated by the motor, said means serving to electrically connect and disconnect the controllable circuit, means serving to supply current to the motor and supplemental of the current supplied to the motor through the said single automatically operating device.

6. In an electrically operated control system, a source of electric energy, an electric motor connected to the source of electric energy, a single automatically operating device interposed in the motor connection for setting the motor in motion, a control T.

e circuit'in the system, a current translating member in the controllable circuit, predetermined time means operated by the motor. said means serving to electrically connect and disconnect the controllable circuit, said means serving to supply current to the motor and supplemental of the current supplied to the motor through the said single automatically operating device and said means also serving to operate a multiple pole relay for closing the supplemental current circuit to the motor, as described.

ARTHUR E. HAFF.

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