Classifications

• • 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
  • H01H9/541—Contacts shunted by semiconductor devices
  • H01H9/542—Contacts shunted by static switch means
• • 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
  • H01H47/02—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for modifying the operation of the relay
  • H01H47/18—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for modifying the operation of the relay for introducing delay in the operation of the relay
• • 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
  • H01H9/541—Contacts shunted by semiconductor devices
  • H01H9/542—Contacts shunted by static switch means
  • H01H2009/545—Contacts shunted by static switch means comprising a parallel semiconductor switch being fired optically, e.g. using a photocoupler

Definitions

• the invention relates generally to a switching circuit for making and breaking capacitive, inductive and resistive load in an electrical circuit, as disclosed in the introductory part of Claim 1.
• Electrical switching devices are known in various embodiments, commonly known by the term "relay”.
• Known electromagnetic relays have been available for several years, but they demand a lot of space, energy, and are besides generating electritical noise at making and breaking. Such devices also require a relatively high controlling power, and are thus precluded for a number of task, e.g. where the controlling is being done from a computer.
• SSR-relays Solid State Relay
• US Patent specification 4,074,333 discloses a device in which these detrimental features by far are eliminated.
• Said device operates by means of first making the load using an electronical coupling means, a bidirectionally controlled, contactless switch, whereupon a mechanical relay connects and holds the load circuit.
• the order of making and breaking is controlled by a dedicated sequence controller.
• Means are provided for controlling the triac, responsive to signals from the sequence controller through a phase detector.
• the phase detector is provided to ensure making and breaking at the point in time where the phase angel in the load circuit equals zero (zero-voltage crossing).
• a signal is fed back from the triac-controller to the sequence controller, which, through the energizing means, provide closing of the electro agnetical relay.
• a disadvantage with the device disclosed in US 4,074,333 is that it comprises a relatively complex circuit including a plurality of relatively complex circuit elements. If this circuit should be designed according to the description, using existing circuit elements, it would become unreasonably expensive. Furthermore, the device would require a relatively great amount of space, so that the device have to be large and expensive, and thus of less commercial interest.
• the present invention is carried out using a minimum of, and simple elements, a fact which results in the circuit does require a minimum of space. Furthermore, the tolerances are not critical for the function of the circuit. All these factors contribute to a very low cost for the manufactured circuit.
• a control voltage 11 is applied, for controling making and breaking of the circuit. If AC voltage is to be used, it ⁇ hold be rectified (not shown in the figure). In the presence of the control voltage 11 a current will flow through a diode 12, a resistor 13, and a light-emitting section 14a of an optical coupler. This will in its turn provide trigging of the light-sensitive section 14b.
• the optical coupler 14a, 14b is of the kind being used to control triacs, and is in addition delaying the making until the phase angle being zero.
• Optically coupler 14b is connected to the control input of a triac 21, which is capable of making a load 22.
• Said load can be inductive, capa ⁇ itive or pure resistive. Provision of voltage to the triac, results in connection of the load.
• the same voltage 11 starts generating an electric field in capacitor 18 through a resistor 17.
• the capacitor 18 will, together with the resistor 17, form a time-delay circuit (RC-network) , which will, in a period of time determined of the selected values of the resistor 17 and capacitor 18, generate a voltage between the base of a transistor 19 and ground, so that the transistor 19 will conduct current through the control coil of a mechanical relay 20a, which shuts a switch 20b of the relay, making the load 22.
• RC-network time-delay circuit
• the capacitor can consequently be of a conciderably less capacity.
• the control voltage is trigging triac 21, and starts charging the capacitor 18, the same control voltage also starts charging capacitor 16 through the resistor 15.
• Resistor 15 and resistor 13 are, together with capacitor 16 forming a time delay circuit. This time delay circuit is utilized in breaking the load connection.
• the RC-network formed of resistor 15, resistor 13, and capacitor 16 will provide current to optical coupler 14a, 14b in a periode of time determined by said RC-network.
• the transistor 19 will immediately be turned off, opening the electromagnetic relay 20a, 20b.
• connection to the load will be maintained by means of the triac 21 until the control voltage entirely disappears when the capacitor 16 is sufficiently discharged.
• the time constant for the RC-network fromed by 13, 15 and 16 should correspond to at least half a period of the load 22. Still, it could be larger, as it is the phase detecting optical coupler observing the breaking being exactly in zero-voltage crossing.

Applications Claiming Priority (3)

Publications (2)

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ID=19891254

Family Applications (1)

Country Status (10)

Families Citing this family (35)

Family Cites Families (14)

• 1988
  • 1988-09-19 NO NO884150A patent/NO168009C/no not_active IP Right Cessation
• 1989
  • 1989-09-18 AU AU42143/89A patent/AU4214389A/en not_active Abandoned
  • 1989-09-18 AT AT89910212T patent/ATE108572T1/de not_active IP Right Cessation
  • 1989-09-18 EP EP89910212A patent/EP0437447B1/de not_active Revoked
  • 1989-09-18 WO PCT/NO1989/000095 patent/WO1990003655A1/en not_active Application Discontinuation
  • 1989-09-18 DE DE68916804T patent/DE68916804T2/de not_active Expired - Lifetime
  • 1989-09-18 JP JP1509517A patent/JPH04501785A/ja active Pending
• 1991
  • 1991-03-11 FI FI911187A patent/FI93402B/fi active
  • 1991-03-19 US US07/671,519 patent/US5283706A/en not_active Expired - Lifetime
• 1992
  • 1992-12-29 LV LVP-92-540A patent/LV10542B/en unknown

Non-Patent Citations (1)

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