US2540558A - Electromagnetic power-current relay - Google Patents

Electromagnetic power-current relay Download PDF

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Publication number
US2540558A
US2540558A US684085A US68408546A US2540558A US 2540558 A US2540558 A US 2540558A US 684085 A US684085 A US 684085A US 68408546 A US68408546 A US 68408546A US 2540558 A US2540558 A US 2540558A
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United States
Prior art keywords
relay
current
coil
beginning
period
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Expired - Lifetime
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US684085A
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English (en)
Inventor
Vingerhoets Antonius Wilhelmus
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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Publication date
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/54—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere
    • H01H9/56—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere for ensuring operation of the switch at a predetermined point in the AC cycle

Definitions

  • closing time of the relay is highly influenced by the place occupied at the moment when the energisation period of the coil of the relay begins relatively to the node of the energizing alternating current.
  • closing time is to be understood here to mean the time which elapses between the said beginning of the energisation period of the coil and the moment when the mechanical contacts are closed.
  • the energizing current is greater as a result of the occurrence of over-currents and the lifting time of the relay is correspondingly shorter. Since the circuit of the coil of a mechanical relay in practice generally exhibits such an inductive character that a phase difference of the order of 90 exists between the energizing current and the energizing voltage, a switching-in of the coil of the relay in a region located between the maximum and the subsequent node of the energizing alternating current practically corresponds to a switching-in between the node and the subsequent maximum of the energizing alternating current.
  • the moment of switching-in of the coil of the relay falls in most cases withinthis region while it is also customary to choose the moment of switching-in as a function of voltage (for example when the coil is energized through a gas-filled r vapour-filled discharge tube which is normally made conductive in the first half of the positive half period of the anode voltage) the beginning of the energisation period of the coil for simplicitys sake will always be considered in this description in the lagging sense relatively to the node of the energizing voltage.
  • the present invention first of all purports to obtain a reduction of the above-mentioned additional delay in the moment of closure of the mechanical contacts, and this in such manner that in an electromagnetic power-current relay fed on alternating current and controlled synchronously, which comprises mechanical contacts, the time constant for the increase of current in the circuit of the coil i given a value smaller than a period of the energizing alternating current, and this so small that in a desired region up to at most 90 later than the node of the energizing alternating voltage a later beginning of the energisation period of the coil yields an efiective current strength through the coil which is substantially equal or greater than with an earlier beginning,
  • Such a relay can be used with particular advantage in devices for resistance welding in which the welding current is switched-in by the relay for exactly such a predetermined period as is desired. This must be effected in a reproducible manner.
  • time lag which is brought about by thecbmp'ara tive increase in current strength. Further, by a correct choice of the smaller. value of the said time constant the said region can cover adefinite range desired.
  • the relation which exists between the values of the currents obtained with an earlier-and a later beginning of the energisation period may also be influenced by a definite choice of the time constant.
  • the liftingtime maybe chosen'such that the diiference between the'current strengths which'according to less the said special control means are utilised the accuracy is increased by the invention.
  • Figure 1 is a diagrammatic presentation of the relationof the values of the currents obtained according to the. inventions.
  • Figure -2 is a diagrammatic presentation of voltage and current relations when a gas-filled tube is used according to the invention.
  • Figure 3 is a schematic presentation of a relay in anopen position and connected to a phase 1 shift networks according to the invention.
  • Figure l is a schematic view of the relay of Figure 3 when in a closed position.
  • the distance AB covers a period of the energizing alternating voltage E which is shown as a normalsinusoidal alternatin voltthe invention occur with a'later beginning of the I 'energisation period (greater current) an "earlier beginning (smaller current) has a corn.- paratively greater influence them when the"nie chanical construction and hence the lifting time together with the friction and the lifting time of the relay are so chosen and adapted to one another that a synchronous switching-in of the mechanicahcontacts is obtained.
  • the moment of the beginning of the energisation period of the coil it is thus possible to close the mechanical contacts on any desired point of the alternating voltage-curve and, consequently, to obtain a-synchronised switching-in which is reproductible again.
  • this region does not extend to the right unlimitedly, but is bound to a limit determined, for example, by a value equal to twice the time constant, when considered from the beginning of the period of energisation. Consequently, by means of a suitable mechanical construction of the relay the lifting time must be limited to a maximum interval and must not extend, for example, over several periods.
  • the saidthreshold value of the relay could be represented by the horizontal little line W, from which can be seen that currents smaller than the ordinate of W do not influence the response of the relay. Consequently, this threshold value also influences the ultimate lifting time of the relay.
  • the region 9 is determined by the point of intersection of the characteristic T and the stationary-current curve I, the region 9 may be chosen at will by a correct choice of the variation of curve T, for which again the time constant of the circuit of the coil is decisive.
  • the closing time of the relay Ti and T1 with an earlier beginning (at A) and with a later beginning (at t) of the energisation period is shown.
  • the mechanical contacts of the relay are switched-in substantially isochronally, which ensues from the small difference between the final points of the times Ti and Ti, ihe point C, which is the final point of the extension shown in dotted line of the lifting time T'i which occurs with a later beginning of the energisation period indicates where the mechanical contacts would close, for example, in the case of a relay of the usual type in which the invention is not utilised.
  • the distance D indicates the additional delay mentioned several times in the preamble of the description while the time which elapses between the earlier and the later beginning of the energisation period is indicated by F, which is thus equal to the distance A-t.
  • the relay may also be switched-in a little later outside the range 6 if the friction of the relay which is to be considered as the cause of the above-mentioned threshold value indicated by the line W admits this.
  • the line W lies higher than in the current region wherein the currents are greater than the ordinate of W, it is possible by switching-in later a little at the right of the range 6 to obtain a current strength substantially equal to that obtained with an earlier switching-in, the more so as the steepness of the current curve associated with the said later switching-in may be greater than the steepness of the current curve corresponding to an earlier switching-in.
  • Figure 2 shows a voltage E which serves as an anode voltage of a gas-filled or vapour-fved controll d discharge tube while the coil of the relay is included in the anode circuit of it.
  • the control voltage at the grid of the tube is indicated E5 and is dephased relatively to the anode voltage by something more than 180, 1. e. by 1 more than 180. Consequently, the region wherein the ignition of the tube can take place amounts to 1.
  • the region 7' cannot be reduced at will since then there is a risl; that the tube would not ignite any more.
  • Electromagnetic relay apparatus comprising a relay having a core portion, a winding portion mounted on said core, an armature portion adapted. to be moved to and from said core portion and contact portions adapted to be opened and closed by the movement of said armature portion, switching means to apply a source of alternating current to said relay for energizing said relay, said relay having a time constant having a value smaller that the period of the volt age impressed on the said coil, said time constant being so relatively small that in a desired range not exceeding later than the node of the energizing alternating voltage, a later beginning of the energizing period of the said coil will cause an effective current to flow through the said coil which is substantially equal to an earlier beginning of the said energizing period of the said coil and means to actuate said switching means to energize said relay at a time period subsequent to said voltage node.
  • Electromagnetic relay apparatus comprising a relay having a core portion, a winding portion mounted on said core, an armature portion adapted to be moved to and from said core portion and contact portions adapted to be opened and closed by the movement of said armature portion, switching means to apply a source of alternating current to said relay for energizing said relay, said relay having a time constant hav ing a value smaller that the period of the voltage impressed on the said coil, said time constant being so small that in a desired range not exceeding 90 later than the node of the energizing alternating voltage, a later beginning of the energizing period of the said coil will cause an effective current to flow through the said coil 7 i which is substantiallyequal to an earlierbeginningv of the said energizing period of the said coil, said time constant and therewith the effective currents occurring with an earlier and a later beginning of the said energizing periods, and said contacts having a friction component and a 010s ing time correlated to said time constant that the
  • Electromagnetic relay apparatus comprising a relay having a core portion, a winding portion mounted on said core, an; armature portion; adapted be moved to and from said core portionenoi contact portions adapted to be opened and closed by the movement of said switching means to apply a source of alternating current to said relay for energizing said relay, said relay having a time constant having a value smaller that the period oi the voltage impressed on the said coil, said time constant being so relatively small that in desired range not exceeding 90 later than the node of the energizing alternating voltage, a later beginning of the energizing period of the said coil will cause an efiective current to flow through the said coil which is substantiallyequal to anearlier beginning of the.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Relay Circuits (AREA)
US684085A 1943-02-02 1946-07-16 Electromagnetic power-current relay Expired - Lifetime US2540558A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL2540558X 1943-02-02

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US2540558A true US2540558A (en) 1951-02-06

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US684085A Expired - Lifetime US2540558A (en) 1943-02-02 1946-07-16 Electromagnetic power-current relay

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US (1) US2540558A (enrdf_load_stackoverflow)
BE (1) BE454196A (enrdf_load_stackoverflow)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2404643A (en) * 1943-03-20 1946-07-23 Gen Electric Electronic electroresponsive apparatus
US2412092A (en) * 1943-04-09 1946-12-03 Farnsworth Television & Radio Electronic timer

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2404643A (en) * 1943-03-20 1946-07-23 Gen Electric Electronic electroresponsive apparatus
US2412092A (en) * 1943-04-09 1946-12-03 Farnsworth Television & Radio Electronic timer

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BE454196A (enrdf_load_stackoverflow)

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