US3673446A - Induction disc type relay - Google Patents

Induction disc type relay Download PDF

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Publication number
US3673446A
US3673446A US91013A US3673446DA US3673446A US 3673446 A US3673446 A US 3673446A US 91013 A US91013 A US 91013A US 3673446D A US3673446D A US 3673446DA US 3673446 A US3673446 A US 3673446A
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United States
Prior art keywords
disc
torque
input signal
induction
type relay
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Expired - Lifetime
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US91013A
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English (en)
Inventor
Mitsuo Watai
Koya Ito
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Hitachi Ltd
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Hitachi Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
    • H02H3/093—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current with timing means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H53/00—Relays using the dynamo-electric effect, i.e. relays in which contacts are opened or closed due to relative movement of current-carrying conductor and magnetic field caused by force of interaction between them
    • H01H53/10—Induction relays, i.e. relays in which the interaction is between a magnetic field and current induced thereby in a conductor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H53/00—Relays using the dynamo-electric effect, i.e. relays in which contacts are opened or closed due to relative movement of current-carrying conductor and magnetic field caused by force of interaction between them
    • H01H53/10—Induction relays, i.e. relays in which the interaction is between a magnetic field and current induced thereby in a conductor
    • H01H53/12—Ferraris relays

Definitions

  • the present invention relates to induction disc type relays.
  • An induction disc type relay is generally used as time lag relay which requires a predetermined time between the application of an input thereto and the generation of its operating output.
  • FIG. 1 there is shown the operating characteristic of a time lag overcurrent relay which is the most frequently used application of the induction disc type relay as a time lag relay and in this figure the abscissa represents the input current (in terms of multiples of the set operating value) and the ordinate represents the operating current (in seconds), while curves (A), (B) and (C) represent what are usually termed an operating time lag characteristics.
  • the curve (A) is generally defined as an inverse and definite'time lag characteristic showing that the operating time becomes shorter as the input current increases, but the: operating time becomes practically constant with the input current exceeding about ten times the value of the set operating value, while the curve (C) is called as a very inverse time lag characteristic showing that the operating time becomes rapidly shorter in inverse proportion to the input current.
  • the curve (B) is called an inverse time lag characteristic which is almost intermediate between the characteristic of the curve (A) and that of the curve (C).
  • time lag characteristics may be suitably selected according to the kinds of apparatus to which overcurrent protection must be afforded, and fault conditions etc.
  • the operating time lag characteristic may be changed to suit any input current, it is necessary to vary the driving torque provided to an induction disc.
  • the characteristic (A) may be obtained if it is so arranged that the driving torque will become constant with a current value exceeding 10 times the operating vaIue,-while the characteristic (C)' may be obtained if it is so arranged that the driving torque remains on the increase so far as the input current is within the illustrated range;
  • the induction disc type relays which are now in practical use may be divided into two broad classes according to the kinds of driving electromagnets used, that is, a transformer (split phase) type relay as shown in FIG. 2 and a shading coil type relay as shown in FIG. 3.
  • the transformer type relay shown in FIG. 2 includes a core 1 provided with a main pole 2 and magnetic poles 3 formed thereon, and a primary coil 4 to which an input is applied and a secondary coil 5 are both wound on the main pole 2 with one end of the secondary coil 5 being wound on a saturable transformer 6.
  • One end of another coil wound on the saturable transformer 6 is connected to a magnetic pole coil 7 wound on the magnetic poles 3.
  • Numeral 8 designates an induction disc rotatably disposed in an air gap between the main pole 2 and the magnetic poles 3.
  • the transformer type relay is well suited to obtain an inverse and definite time lag characteristicsuch as the characteristic (A), it has a drawback in practical use in that the construction is complicated compared to the shading coil type relay, that the operation of winding the primary coil 4 and the magnetic pole coil 7 is a diflicult undertaking and hence the working efliciency is low, and that the apparent power consumption in tenns of voIt-amperes is high.
  • the driving electromagnet portion of the shading coil type relay includes a core 9 on which is wound an exciting coil 10 to which an input is applied, and the air gap portions of the core 9 are formed into the shape of forks by means of a slot 11 so that a shading coil 12 is wound on one of the respective forked poles.
  • An induction disc 13 is also disposed in the air gap formed by the core 9 so that the induction disc 13 rotates about a shaft 14 within the air gap.
  • an operating output is produced when the disc 13 rotates 'through a predetermined angle, that is, an operating output is delivered at a specified time after the application of the input.
  • the shading coil type relay performs the time lag action thereof, and its advantages include a very simple construction which can be completed by simply mounting the shading coils and hence good working ability and a low apparent power consumption (volt-ampere) as compared with the transformer type relay are obtained.
  • the shading coil type relay has a relatively large air gap portion in the magnetic circuit thereof, it is difficult to obtain a definite time lag characteristic, even if a core material is used which exhibits an almost rectangular hysteresis characteristic, and so the shading coil type relay is suited for applications where it is desired to obtain such an operating time characteristics as the characteristics (B) and (C).
  • the present invention aims-at eliminating the deficiencies described above and therefore one object of the present invention is to provide an induction disc type relay of a shading coil type which is capable of easily obtaining not only an inverse time lag characteristic, but also an inverse and definite time lag characteristic.
  • Another object of the present invention is to provide an induction disc type relay which is very simple in construction and low in power consumption (volt-ampere).
  • a further object of the present invention is to provide an induction disc type relay which is inexpensive and capable of achieving the expected effects without using any special and expensive material as the core material.
  • FIG. 1 is a diagram showing the time lag characteristic of a time lag overcurrent relay which is the most typical of the applications of induction disc type relays;
  • FIG. 2 is a schematic diagram showing the driving section of a transformer type relay
  • FIG. 3 is a schematic diagram showing the driving section of a prior art induction disc type relay
  • FIG. 4 is a schematic diagram showing the principal part of an embodiment of the present invention.
  • FIG. 5 is a plan view schematically showing the induction disc used in the device of FIG. 4;
  • FIG. 6 is a diagram for explaining the operation of the device of the present invention.
  • FIG. 7 is a schematic diagram showing the principal part of another embodiment of the present invention.
  • FIG. 4 illustrates diagramatically the driving section of an induction disc type relay according to the present invention.
  • numeral designates an exciting coil wound on a core 16, 17 a rotary disc which rotates about a shaft 18 within air gaps, g, and 3 as shown in FIG. 5, thereby closing the contacts which are not shown.
  • the magnetic pole portions where the magnetic flux in the core 16 interlinks the disc 17 are divided into pairs of magnetic poles 19, 19 and 20, 20' and each of these poles 19, 19 and 20, 20' is in turn forked so that shading coils 21, 21', 22 and 22' are mounted at the respective positions of the forked poles.
  • shading coils 21, 21', 22 and 22 are positioned as shown in the figure so that torques produced at the respective shading coils tend to oppose each other.
  • Numeral 23 designates a restraining spring having one end connected to the shaft 18 and the other end to some relay member so that when the disc 17 rotates in the normal'direction of movement thereof, the spring 23 produces a definite restraining torque in the direction opposite to the direction of movement of the disc 17.
  • a permanent magnet (braking magnet) is separately provided to retard the motion of the induction disc 17 so as to give a time lag as with those induction disc type relays which are now in practical use.
  • the magnetic flux produced in the magnetic poles 19, 19' interlinks or passes through the disc 17 to rotate it clockwise, thereby producing an operating torque in the direction to close the relay contacts.
  • the magnetic flux produced in the magnetic poles 20, 20 rotates the disc 17 counter-clockwise to produce a restraining torque in the direction to restraint the closing of the contacts.
  • the disc 17 will be driven by the difference between the torque produced by the poles 19, 19' and that by the poles 20, 20'.
  • the air gap g, of the magnetic path including the poles 19, 19' may be selected to be smaller than the air gap g; of the magnetic path including the'poles'20, 20' so that the reluctance of the former will remain smaller than that of the latter until the magnetic path between the points A and B become saturated, while the cross-section of the poles 19, 19' may be made smaller than that of the poles 20, 20' so that this portion will become saturated first.
  • qS designates the magnetic flux passing 6, the poles l9, I9; 45 the magnetic flux passing through the poles 20, 20'; T, and T, torques produced by the magnetic fluxes d), and respectively.
  • K may be varied by means of the reluctance of the magnetic path including the poles 20, 20', i.e., the air gap g the cross-section of the magnetic poles etc., while K may be varied by means of the shading coils 22, 22.
  • the constant K will be zero in the absence of the shading coils 22, 22'.
  • the value of the bracketed second member on the right side of the equation (9) can not be reduced to zero, whereas if, for example, the constant K of the restraining torque T is changed to K, and the value of this constant K, is so chosen that the operating torque T, and a restraining torque T, increase at the same rate, the value of this bracketed member can be almost reduced to zero so that the combined torque T can remain constant with respect to the input after a certain point has been reached.
  • the time lag characteristic of such a relay can take the form of an inverse and definite time lag v characteristic as shown by the curve (A) in FIG. 1.
  • a core adapted to be energized by an exciting coil is formed with two pairs of magnetic poles for producing an operating torque and a restraining torque, respectively, so that any desired time lag characteristics ranging from an inverse and definite time lag characteristic to a very inverse time lag characteristic can be obtained with varying values of the restraining torque which may be accomplished by changing the related constants by means of the air gaps and the crosssection of the poles which produce the restraining torque.
  • one of the very important features of the present invention resides in that an inverse and definite time lag characteristic which has been considered as hardly attainable with conventional relays, particularly the induction disc type relays, is now obtainable with extreme easiness according to the present invention.
  • FIG. 7 designate electromagnets for producing an operating torque and a restraining torque, respectively, and the electromagnet 23 comprises a core 27 which is provided with magnetic poles 26, 26 with shading coils 25, 25' and on which is wound an exciting coil 28 to which an input is applied, whereby the operating torque in the direction of an arrow 30 is produced on an induction disc 29 rotatably disposed between the magnetic poles 26, 26.
  • the electromagnet 24 similarly comprises a core 33 which is provided with magnetic poles 32, 32.with shading coils 31, 31 and on which is wound an exciting coil 34 to which the same input as with the electromagnet 23 is applied, so that a restraining torque in' the direction of an arrow 35 which is opposite to the direction of the operating torque produced by the electromagnet 23, is produced on the disc 29 or some other disc which is mechanically coupled to the disc 29.
  • the same effects as obtained with the embodiment of FIG. 4 can be achieved by suitablyselecting the value of the constant of the electromagnet 24, such as by varying the air gap of core 33 with respect to core 27 of electromagnet 23.
  • means are provided to produce both an operating torque and a restraining torque, i.e., a rotational torque on an induction disc, whereby the means for applying the restraining torque may be controlled to suitably select and regulate the restraining torque so as to obtain any desired characteristics including not only an inverse time lag characteristic and a very inverse time lag characteristic, but also an inverse and'definite time lag characteristic.
  • any good time lag characteristic can be obtained with inexpensive relays, since such a good characteristic is obtainable without using specific and expensive alloys such as Perrnalloy but using inexpensive material such as silicon steel as a core material.
  • an induction disc type relay including an induction disc and means for applying a rotational torque to said disc
  • said means for applying a rotational torque to said disc comprises:
  • first means responsive to an input signal, for supplying a first operating torque to rotate said disc in a first direction
  • first and second means responsive to said input signal to which said first means is responsive, for supplying a second operating torque to rotate said disc in a direction opposite to said first direction
  • said first and second means each comprises a shading coil magnetic pole structure having differently spaced air aps mounted on the single core piece, where y, the resultant torque applied to rotate said disc results from the application of the same input signal to said first and second means, so that a desired inverse time lag characteristic can be accurately obtained.
  • An induction disc type relay according to claim 2 including a singular input coil mounted on said core structure to which said input signal is applied.
  • an induction disc type relay including an induction disc and means for applying a rotational torque to said disc
  • said means for applying a rotational torque to said disc comprises:
  • first means responsive to an input signal, for supplying a first operating torque to rotate said disc in a first direction
  • second means responsive to said input signal to which said first means is responsive, for supplying a second operating torque to rotate said disc in a direction opposite to said first direction
  • said first and second means each comprises a shading coil magnetic pole structure having differently spaced air gaps mounted on separate core pieces and including a pair of input coils mounted on said pieces and having the inputs thereof each receiving said input signal so that said input signal will be applied to each of said core pieces and, thereby, to said shading coil magnetic pole structure, whereby, the resultant torque applied to rotate said disc results from the application of the same input signal to said first and second means, so that a desired inverse time lag characteristic can be accurately obtained.

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US91013A 1969-11-21 1970-11-19 Induction disc type relay Expired - Lifetime US3673446A (en)

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JP44092969A JPS4839915B1 (fr) 1969-11-21 1969-11-21

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4115714A (en) * 1976-03-04 1978-09-19 General Time Corporation Stepping motor
US4639626A (en) * 1985-04-26 1987-01-27 Magnetics Research International Corporation Permanent magnet variable reluctance generator
US4757224A (en) * 1985-04-26 1988-07-12 Magnetics Research International Corp. Full flux reversal variable reluctance machine
US20130093278A1 (en) * 2011-10-12 2013-04-18 Industrial Technology Research Institute Rotational kinetic energy output device
US20150364979A1 (en) * 2014-06-17 2015-12-17 Transducing Energy Devices, Llc Magnetic electricity generator

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57156940A (en) * 1981-01-29 1982-09-28 Bishiyuru Yohan Guide member and its manufacture

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2027846A (en) * 1934-02-15 1936-01-14 Gen Electric Reversible shaded pole motor
US2079492A (en) * 1933-08-23 1937-05-04 Gen Electric Electrical regulating system
US2094986A (en) * 1930-08-27 1937-10-05 Allis Chalmers Mfg Co Electric current responsive device
US2110417A (en) * 1937-02-08 1938-03-08 Duncan Electric Mfg Co Electric meter
US2110686A (en) * 1936-03-24 1938-03-08 Gen Electric Electroresponsive device
US2110391A (en) * 1936-11-19 1938-03-08 Arthur L Davis Maximum and minimum voltmeter

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2094986A (en) * 1930-08-27 1937-10-05 Allis Chalmers Mfg Co Electric current responsive device
US2079492A (en) * 1933-08-23 1937-05-04 Gen Electric Electrical regulating system
US2027846A (en) * 1934-02-15 1936-01-14 Gen Electric Reversible shaded pole motor
US2110686A (en) * 1936-03-24 1938-03-08 Gen Electric Electroresponsive device
US2110391A (en) * 1936-11-19 1938-03-08 Arthur L Davis Maximum and minimum voltmeter
US2110417A (en) * 1937-02-08 1938-03-08 Duncan Electric Mfg Co Electric meter

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4115714A (en) * 1976-03-04 1978-09-19 General Time Corporation Stepping motor
US4639626A (en) * 1985-04-26 1987-01-27 Magnetics Research International Corporation Permanent magnet variable reluctance generator
US4757224A (en) * 1985-04-26 1988-07-12 Magnetics Research International Corp. Full flux reversal variable reluctance machine
US20130093278A1 (en) * 2011-10-12 2013-04-18 Industrial Technology Research Institute Rotational kinetic energy output device
US8643245B2 (en) * 2011-10-12 2014-02-04 Industrial Technology Research Institute Rotational kinetic energy output device
US20150364979A1 (en) * 2014-06-17 2015-12-17 Transducing Energy Devices, Llc Magnetic electricity generator
US9742252B2 (en) * 2014-06-17 2017-08-22 Transducing Energy Devices, Llc Magnetic electricity generator

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