US2254941A - Relay system - Google Patents

Relay system Download PDF

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Publication number
US2254941A
US2254941A US194863A US19486338A US2254941A US 2254941 A US2254941 A US 2254941A US 194863 A US194863 A US 194863A US 19486338 A US19486338 A US 19486338A US 2254941 A US2254941 A US 2254941A
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United States
Prior art keywords
relay
voltage
circuit
actuating element
capacitance
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US194863A
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English (en)
Inventor
Friedlander Erich
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Westinghouse Electric Corp
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Westinghouse Electric Corp
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Filing date
Publication date
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Application granted granted Critical
Publication of US2254941A publication Critical patent/US2254941A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
    • H01H47/22—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for supplying energising current for relay coil
    • H01H47/26—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for supplying energising current for relay coil having thermo-sensitive input

Definitions

  • This invention relates to a control system and it has particular relation to a relay control system energized through a tuned circuit.
  • a condenser may be connected in series with the winding of the relay and tuned to respond to a predetermined condition of an alternating current circuit.
  • a condenser may be connected in series with the winding of the relay and tuned to respond to a predetermined condition of an alternating current circuit.
  • Resonant circuits may be employed which do not change their characteristics during relay actuation provided separate iron core choke coils and series condensers are employed. If a choke coil in a resonant circuit for relay actuation is given a direct current premagnetization dependent on the potential of a tuning condenser from a rectifier connected in series with the resonant circuit, stable operation may be obtained.
  • Such 3 systems however have the disadvantage of requiring a number of additional elements, such as choke coils and rectifiers.
  • a control system wherein a tuned or resonant circuit is employed for actuating a switch or relay device having an actuating element which does not change the inductance or capacitance of the tuned circuit during the actuation of the device.
  • a thermal switch or relay has been found suitable.
  • the thermal switch may have an actuating element comprising a wire or a bimetallic unit which, when heated, changes in dimension to operate the switch contacts.
  • Such a system does not change its inductance or capacitance during actuation, the actuating element being, in effect, a constant resistance.
  • a further object of my invention is to provide a control relay system employing a thermally actuated relay controlled by a tuned circuit.
  • Another object of my invention is toprovide an accurate and sensitive control system responsive to two different values of a variable condition.
  • a still further object of my invention is to provide a tuned control system for maintaining a variable condition accurately between two predetermined limits.
  • Figure l is a diagrammatic view of a thermally actuated relay associated with a tuned control circuit
  • Fig. 2 is a graphic representation of the voltage-current relationships in the control system of Fig. 1;
  • Fig. 3 is a diagrammatic view of a modification of the circuit of Fig. 1;
  • Figs. 4, 5 and 6 are diagrammatic views of various modifications of circuits responsive to two different conditions of an alternating current circuit.
  • Fig. 7 is a graphic representation of the voltage current relationships of the circuit illustrated in Fig. 6.
  • Figure 1 depicts a tuned circuit comprising a capacitance l and a choke coil or inductance 2 having an iron core connected in series across the conductors L1 and L2 of an alternating current circuit.
  • a relay 3 has an actuating element 4 connected in parallel with the capacitance.
  • the relay actuating element 4 is so selected that its impedance remains constant during the actuation of the relay, and a thermal actuating element has been found desirable for this purpose.
  • the thermal element 4 moves a pivoted contact member 5 into engagement with a fixed contact member 6.
  • a pair of output terminals 1, 8 are provided for the control system, and are connected respectively to the fixed contact member 6 and the conductor L2.
  • the iron core choke coil 2 and the capacitance I are so proportioned as to produce the voltagecurrent relationships shown in Fig. 2, wherein voltage is represented by ordinates and current by abscissae.
  • the voltage across the choke coil 2 with respect to the current flowing therethrough is shown by a curve EL, the voltage across the capacitance (shown above the current axis for convenience) by a curve (Ec), and the resultant voltage across the tuned circuit by a curve E.
  • the resultant voltage curve E has a voltage-current relationship such that the current increases slowly with respect to voltage cuit.
  • L1, L2 will be accompanied by a large increase of current through the tuned circuit and by an accompanying large increase of voltage across the capacitance I. Since the relay 3 is responsive to the voltage across the capacitance I, such an increase of voltage positively energizes the relay to close its contact members 5, 6. Any device to be controlled by the relay 3 may be connected to the outputterminals 1, 8.
  • the relay 3 of Fig. 1 responds to a change in voltage, it may be connected to respond to other Variable conditions. For ex.-
  • the temperature may be employed for controlling an alternating voltage which is supplied to a relay system similar to that shown in Fig. 1. If it is desired to have the relay respond to current changes, the current may be passed through a resistance, and the voltage drop across the resistance may be employed for energizing the above relay system. Since-tuned circuits may be designed to provide an'appreciable current change in response to a variation in frequency, a similar relay system may be designed for actuation in accordance with the frequency of an alternating current cir- If the frequency and voltage of an alternating-current circuit both vary and it is desired to make the relay responsive to voltage only, a voltage proportional to the frequency change may be introduced in series with the tuned circuit. 1
  • actuating element t of the relay 3 in Fig. 1 is in parallel with the capacitance I, it may be connected in series with the tuned circuit as shown in Fig. 3 wherein the reference characters let to 8a correspond respectively to the reference characters I to 8 of Fig. 1.
  • a pair of fixed contact members maybe employed with each of the relays 3, one being contacted by the movable member 5 when the actuating element t is deenergized, and the other being contacted by the movable element ii when the actuating element :3 is energized.
  • Each of the fixed contacts may be employed for control purposes.
  • Fig. 4 illustrates a system designed to maintain a certain variable, such as voltage, between two predetermined limits.
  • a capacitance lb, 2 In Fig. 4, a capacitance lb, 2,
  • berelay 3c which is similar in construction to the relay 3, is connected with its actuating element to in series with a tuned parallel circuit 9, comprising a capacitance l0 and an iron core choke coil II, across the conductors L1, L2.
  • the fixed contact member to of this relay 3c is connected to a terminal 12.
  • the first relay 3b is adjusted to close its contact members when the voltage across the conductors L1, L2 rises above a predetermined value, Whereas the tuned circuit 9 is proportioned to increase the current through, and actuate the relay 30 when the voltage across the conductors L1, L2 falls below a predetermined value.
  • the output from these relays 3b, 30 may be employed for controlling a motor 13, which may be the operating motor for a voltage regulator such as a step transformer.
  • the motor it may be a two-phase motor having a central lead connected to the terminal 8b, and two outer leads connected to the terminals lb, i2. Across the two outer leads of the motor i3, a condenser ii is connected for controlling the phase relationships in the two windings of the motor.
  • the motor I3 Under operating conditions, if the motor I3 is connected to the conductors L1, L2 through the terminals lb, 8?), it will rotate in one direction, whereas if the motor is connected through the terminals 8b, !2, it will rotate in the opposite direction and may be used therefore for increasing or lowering the voltage across the conductors L1, L2 to compensate for any departure of this voltage from a predetermined value.
  • an auxiliary relay 3d similar to the relay 3, may have its actuating element 40!, connected between the fixed contact member 6b of the relay 3b and the conductor L2. Because of this connection, the contact members 5d, Ed of the relay 3d will be closed when the contact members 52), 6b of the relay 3'0 are closed. The contact members 5d, 6d are connected between the fixed contact member 51) and the lower end of the actuating element ib of the relaylib.
  • relay 3d But if the potential variation is relatively small, the action of the relay 3d will cause the contact members 5b, 6b to reopen after a brief interval and result in intermittent operation of the motor it.
  • a similar relay 3D and resistance element l5 are shown for the thermal actuating element 40 of the relay 30.
  • a condenser I6 may be connected across each pair of contacts.
  • the control of the thermal relays is very sensitive and accurate. Therefore, the low voltage and high voltage relays of Fig. 4 may be adjusted so that the difference between their operating limits is very small;
  • a capacitance l1 and a chock coil I8 are connected in series across the conductors L1, L2.
  • Two relays 3e and [9 are provided for actuation by the voltage across the condenser II.
  • the first relay 3c is similar to those previously described, and is connected to be actuated when a variable condition, such as voltage, of the conductor L1, L2 rises above a predetermined value.
  • the second relay l9 has a pair of normally closed contact members 20, 2
  • the actuating element 22 is con- By varying the tap 24 the operating points of I the relays 3e, 19 may be controlled as desired. Since a displacement of the tap 24 introduces resistance in series with one of the actuating elements while reducing the resistance in series with the other actuating element, the total resistance across the capacitance ll tends to remain constant.
  • a second adjustment is provided by connecting a second divider 25 across a portion of the choke coil [8, the divider having a movable tap 26 con
  • of the relays 3e, l9 are connected respectively to terminals 1e and l2e and a third terminal Be is connected to the line L2.
  • FIG. 6 Another relay system that is energized from a single tuned circuit is shown in Fig. 6.
  • a capacitance 2! and a choke coil 28 are connected in a series tuned circuit across the conductors L1, L2.
  • a pair of relays 3 3g which are similar to those shown in Figs. 1 to 4, are connected for energization from this tuned circuit.
  • the first relay 3f has its actuating element 4 1 connected directly across the capacitance 21.
  • the second relay 3g has its actuating element 49' connected across the capacitance 21 and a portion 29 of the choke coil 28.
  • the circuit containing the capacitance 27 and choke coil 28 is so proportioned that for a normal current In the voltage across the capacitance 21, represented by the ordinate ab, is equal to the voltage bc across the capacitance plus that portion 29 of the choke coil employed for actuating the relay 39.
  • Fig. 6 may be employed similarly to the arrangement shown in Figs. 4 and 5, the output terminals If, 8 and 12 of Fig. 6 corresponding to the terminals lb, 8b and I2 of Fig. 4.
  • the energizing circuit for the relay 3 could be similar to that employed for the relay 3b.
  • a decrease in the voltage across the conductors L1, L2 would deenergize the modified relay 30, thereby closing the contact members of the modified relay.
  • the action of the auxiliary relay 3d in such a case should be modified to increase the current fiowing in the actuating element of the modified relay 30.
  • An auxiliary relay may be employed for increasing or decreasing the current flowing in the actuating element of any of the relays shown in Figs. 5 and 6 in a manner analogous to the employment of the relay 3d of Fig. 4.
  • Protective condensers similar to the condenser l8 of Fig. 4 also may be employed for these other relays.
  • a control system a source of alternating energy; a plurality of electroresponsive control devices, each of said control devices having a thermal actuating element; and energizing means, including at least one tuned circuit for energizing said actuating elements from said source, said energizing means including impedance means adjustable for decreasing the flow of energy to one of said actuating elements and simultaneously increasing the flow of energy to another of said actuating elements.
  • a source of alternating energy a tuned circuit connected for energization from said source, said tuned circuit including a capacitance member and an inductance member, a first electroresponsive device having a thermal actuating element connected for energization in accordance with the voltage across said capacitance member, and a second electroresponsive device having a thermal actuating element connected for energization in accordance with the resultant voltage across said capacitance member and a portion of said inductance memher.
  • a source of alternating energy a source of alternating energy
  • a first electroresponsive control device having a thermal actuating element, a 'series tuned circuit for energizing said actuating element from said source, a tuned parallel circuit
  • a second electroresponsive control device having a thermal actuating element connected for energization from said source through said tuned parallel circuit.
  • a source of alternating energy a first relay device having a pair of normally open contacts and a thermally actuated closing element; a second relay device having a pair of normally closed contacts and a thermally actuated'opening element; and energizing means, including at least one tuned circuit, for energizing said thermal elements from said source.
  • a source of alternating current subject to variation from a predetermined condition an electroresponsive control device having fixed-impedance actuating means, and tuned circuit energizing means for supplying energy from said source to said actuating means, said electroresponsive control device including control means effective When the variation of said source is in one direction and additional control means effective when the Variation of said source is in the opposite direction from said predetermined condition.
  • a source of alternating current subject to variation from a predetermined voltage an electroresponsive control device having fixed-impedance actuating means, and tuned circuit energizing means for supplying energy from'said source to said actuating means, said electroresponsive control device including control means operative when the voltage of said source increases beyond a predetermined point, and additional control means operative when the voltage of said source decreases beyond a predetermined point, said energizing means being more effective for variations beyond one of said predetermined points than for variations adjacent said predetermined voltage.
  • a source of alternating current a tuned circuit energized from said source, said tuned circuit including an inductive reactance and a capacitive reactance in series; and an electroresponsive device having a fixedimpedance actuating element connected across only one of said reactances.
  • a source of alternating current a tuned circuit energized from said source, said tuned circuit including an inductive reactance and a capacitive reactance, and an electroresponsive device having a plurality of thermal actuating elements connected for energization in accordance With the condition of one of said reactances, said actuating elements being energized to different degrees.
  • control device for an alternating current system; a circuit having a non-linear voltampere characteristic; control means; fixed-impedance, heat-responsive actuating means for said control means including an electrical resistance heater element; means for passing electrical current flowing through at least part of said circuit directly through said electricalv resistance heater element for supplying heat to said actuating means, said actuating means being responsive to heat developed by said electrical cur rent flowing in said electrical resistance heater element for operatin said control means; and means responsive to an operation of said control means for varying the impedance offered to said electrical current.

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  • Relay Circuits (AREA)
US194863A 1937-03-10 1938-03-09 Relay system Expired - Lifetime US2254941A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2254941X 1937-03-10

Publications (1)

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US2254941A true US2254941A (en) 1941-09-02

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US194863A Expired - Lifetime US2254941A (en) 1937-03-10 1938-03-09 Relay system

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US (1) US2254941A (enrdf_load_stackoverflow)
BE (1) BE426692A (enrdf_load_stackoverflow)
FR (1) FR834427A (enrdf_load_stackoverflow)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2415348A (en) * 1943-06-17 1947-02-04 John E Haigney Projectile

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FR834427A (fr) 1938-11-21
BE426692A (enrdf_load_stackoverflow)

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