WO1996026449A1 - Fault-detection method and apparatus for electrically heated glass panes - Google Patents
Fault-detection method and apparatus for electrically heated glass panes Download PDFInfo
- Publication number
- WO1996026449A1 WO1996026449A1 PCT/FI1996/000108 FI9600108W WO9626449A1 WO 1996026449 A1 WO1996026449 A1 WO 1996026449A1 FI 9600108 W FI9600108 W FI 9600108W WO 9626449 A1 WO9626449 A1 WO 9626449A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- transformer
- circuit
- electric
- magnetic circuit
- power
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/84—Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
- G01R15/183—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers using transformers with a magnetic core
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B1/00—Details of electric heating devices
- H05B1/02—Automatic switching arrangements specially adapted to apparatus ; Control of heating devices
- H05B1/0227—Applications
- H05B1/023—Industrial applications
- H05B1/0236—Industrial applications for vehicles
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
- G01R31/282—Testing of electronic circuits specially adapted for particular applications not provided for elsewhere
- G01R31/2825—Testing of electronic circuits specially adapted for particular applications not provided for elsewhere in household appliances or professional audio/video equipment
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
- H05B2203/035—Electrical circuits used in resistive heating apparatus
Definitions
- the present invention relates to a method according to the preamble of claim 1 for fault detection in electric glass panes.
- the method also concerns an apparatus for fault detection in electric glass panes.
- the surface tempera ⁇ ture of the glass can be elevated to a desired value by feeding the conducting film with at a controlled level of electric power.
- the thickness of the conducting film must be selected very accurately so that the film is transmis- sive to the wavelength range of visible light, while on the other hand it must also be capable of effectively reflecting thermal radiation back to the interior spaces.
- An additional constraint related to production techniques is that only a few materials are suited for use as the conducting film. Therefore, the surface resistivity (sheet resistivity) values R ⁇ of selective glasses fall in the range 15-25 ohm so that a typical value of the surface resistivity is 19 ohm. Accordingly, the end-to- end resistance of a single glass pane (height x width) can be computed from the formula
- the maximum surface power dissipation permitted for a window pane is typically in the range 50 - 600 W/m 2 . Therefore, the maximum allowable input power levels will be exceeded in a great number of cases for windows with normal dimensions if the window is directly connected to the mains voltage.
- electrically heated glass pane elements are conventionally fed from the mains voltage either connect ed in series for a sufficiently high total resistance, o alternatively, having the glass pane elements connected to a lower voltage via a suitable transformer circuit.
- a novel type of heating power control is the time-switched input power feed control in which the mains voltage is applied in a time-limited manner, whereby a zero-power control cycle is inserted between the power-on control cycles.
- the goal of the invention is achieved by implementing th supply voltage feed to the fault-detection circuit by means of inductive coupling to the mains power feed con ⁇ ductor of the heated window pane so that said inductive coupling circuit is fed during the zero-power control cycles of the input power feed control period via an auxiliary power feed circuit connected in parallel with the terminals of the primary power switching circuit, whereby the auxiliary power feed is limited by means of series capacitor.
- the method according to the invention is characterized by what is stated in the characterizing part of claim 1.
- the fault-detection apparatus is characterized by what is stated in the characterizing part of claim 5.
- the invention offers significant benefits.
- the arrangement according to the invention provides con ⁇ tinuous supply voltage to the fault-detection circuit independently from the input power feed control status, which may be active or nonactive.
- the system may addi- tionally serve as a burglary alarm.
- the system can be installed in a place concealed from unauthorized people, whereby a person possibly attempting a burglary or vandalism has no means of knowing whether the electric glass pane system is provided with an alarm facility or not.
- the present arrangement is suited for use in con ⁇ junction with all conventional input power controller types and the function of the apparatus is not dependent on the power-on control cycle duration or the power- on/power-off duty cycle.
- the components of the apparatus are inexpensive, and moreover, the apparatus can be made small due to the small number of components required.
- Figure 1 is a block diagram of a circuit arrangement according to the invention.
- Figure 2 is a circuit detail of the arrangement shown in Fig. 1; and Figure 3 is a circuit diagram of an apparatus according to the invention complemented with a backup power supply circuit.
- the fault-detection arrangement shown therein is intended for use in an environment having at least one electrically heated glass pane 1 con ⁇ nected in series with a power feed conductor 2, whereby electric input power feed to the glass panes can occur through switching the power feed on and off by means of a switch 7.
- Single-phase feed is typically used as the supply 8 for window pane heating.
- the apparatus is provided with toroidal transformer unit 13 with the feed conductor 2 threaded through the opening of its magnetic circuit 3.
- the fault-detection circuit 6 obtains its supply voltage either directly via a winding 5, whereby the energy induced by the conductor 2 in the toroidal magnetic circuit 3 is transferred via the winding 5 to the circuit 6.
- the trans- former structure 13 acts as a current transformer.
- an auxil ⁇ iary power feed circuit connected in parallel with the switch terminals 7 feeds energy via a winding 4 to the magnetic circuit 3 that further transfers the energy to the electric input power feed detecting circuit 6.
- the transformer structure 13 acts as a voltage transformer. In this manner the fault-detecting circuit 6 in its simplest form can sense the presence of electric energy invoked by alternating electromagnetic induction in the magnetic circuit 3. If no electric power feed is sensed, the detecting circuit issues an alarm signal.
- the capacitor 9 of the auxiliary power feed circuit is dimen ⁇ sioned so that the auxiliary power feed circuit will not cause excessive load in the system while yet supplying sufficient energy for the detecting circuit 6 to trigger the circuit.
- a suitable capacitance value of the capacitor is, e.g., in the range of approx. 0.01 - 0.1 ⁇ F.
- any other suitable transformer core structure capable of inductively transferring the required sensing energy to the fault-detecting circuit 6 may be employed.
- a suitable triggering power level for the detecting circuitry is, e.g., in the range 200 - 500 m .
- the triggering power level is adjusted by varying the number of turns in the windings 4 and 5 as well as the number of turns of the conductor 2 wound about the core of the magnetic circuit 3.
- the following table gives typical guideline values for the different number of turns of the power feed conductor 2 for different current levels in the conductor.
- a typical fault-detection apparatus comprises a rectifier 10 followed by a low-pass filter, which in the present case is implemented as an RC circuit 11.
- a suitable time constant for the RC circuit 11 is, e.g., in the range 20 - 100 ms.
- the rectified, filtered sensing signal is in turn taken to a relay 12 arranged to open/close an alarm circuit at the loss of the sensing signal.
- the relay 12 may be replaced by any digital sensing means based on solid-state devices.
- the circuit configuration of the apparatus is shown incorporating a backup power supply circuit.
- the contactor K2 When the mains voltage (230 VAC) is switched on, the contactor K2 is energized thereby opening the con ⁇ tacts 21-22, 31-32 and 41-42. These contacts disconnect the 12 V backup power supply circuit from the alarm cir- cuit(s). Simultaneously, the contact 15-14 is closed.
- the contactor K3 When the contact 15-14 of contactor K2 is closed, the contactor K3 is energized and contacts 21-22 and 31-32 open. These contacts give additional isolation in the disconnection of the backup power supply circuit. Con ⁇ tacts 23-24 and 15-14 are simultaneously closed, thereby switching the input power on to the electric heated glass pane system 1. Subsequently, the heating system which includes a thermostat for the electric glass pane and an alarm system commences operation in the same manner as the above-described electric glass pane system for burglary alarm.
- the alarm relay Kl With the mains feed switched on, the alarm relay Kl remains energized by the sensing voltage thus keeping the alarm circuit closed irrespective of whether the thermo ⁇ stat is open or close, provided that the electric glass pane circuit is intact.
- the contac ⁇ tors K2 and K3 Upon the disconnection of the mains supply, the contac ⁇ tors K2 and K3 release, whereby the electric glass pane system remains isolated from the mains on both the live and neutral ends of its feed circuit, and the backup power supply circuit is connected to feed the sensing circuit.
- the alarm relay Kl is connected to the positive potential of the backup power supply via its contact
- the alarm relay Kl remains energized thus keeping the alarm circuit closed provided that the electric glass pane circuit is intact.
- the purpose of the capacitor Cl is to prevent a direct short circuit over the voltage winding of the toroidal transformer Ml in the case that the mains supply is on while the thermostat contact is closed.
- capacitor C2 The purpose of the capacitor C2 is to block the DC path from the rectifier back to the toroidal transformer winding when the mains supply is disconnected.
- the purpose of the capacitor C3 is to delay the release of the alarm relay Kl for the duration of contactor energization and thermostat contact switchover requiring a delay of less than one second typical.
- the circuit 25 includes a mechanical antitamper switch serving to activate the alarm circuit if the enclosure of the apparatus is opened.
- Elements 20 are fuses.
- the invention is also suited for use in systems having the electric glass panes fed with a low-voltage supply via a transformer.
- the heating-power-controlling switch is typically located in the primary circuit of the step-down transformer.
- the embodiment according to the present invention is particularly advantageously used in conjunction with a zero-voltage-switching power feed system in which each power-on cycle starts and stops at the zero-crossing point of sinusoidal AC supply voltage.
- magnet ⁇ ic circuit refers to any magnetic circuit suitable for use in a transformer such as a core made from a ferro ⁇ magnetic material.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measurement Of Current Or Voltage (AREA)
- Control Of Resistance Heating (AREA)
Abstract
The invention relates to a method and apparatus for fault detection of electric glass panes in an electric glass pane system (1, 2, 7) operated with time-switched-type of input power feed control. According to the method, the mains power feed conductor (2) of the electric window pane system (1) is adapted to pass through a transformer assembly (13) so that electric power is transferred to the magnetic circuit (3) of the transformer (13), the electric power level in the magnetic circuit (3) of the transformer (13) is detected, and to the magnetic circuit (3) of the transformer (13) is additionally fed electric power via an auxiliary power feed circuit connected in parallel with the input feed power controlling switch (7), whereby the magnetic circuit (3) of the transformer (13) is kept energized at all times as long as all the panes (1) of the electric window pane system are intact.
Description
Fault-detection method and apparatus for electrically heated glass panes
The present invention relates to a method according to the preamble of claim 1 for fault detection in electric glass panes.
The method also concerns an apparatus for fault detection in electric glass panes.
So-called selective glasses incorporating a conducting film have gained wide popularity also in applications to smaller buildings. In such glasses, the surface tempera¬ ture of the glass can be elevated to a desired value by feeding the conducting film with at a controlled level of electric power. The thickness of the conducting film must be selected very accurately so that the film is transmis- sive to the wavelength range of visible light, while on the other hand it must also be capable of effectively reflecting thermal radiation back to the interior spaces. An additional constraint related to production techniques is that only a few materials are suited for use as the conducting film. Therefore, the surface resistivity (sheet resistivity) values R^ of selective glasses fall in the range 15-25 ohm so that a typical value of the surface resistivity is 19 ohm. Accordingly, the end-to- end resistance of a single glass pane (height x width) can be computed from the formula
Rgiaββ " Ro-k/1, where
k = interelectrode distance (e.g., height of glass pane) 1 = length of electrodes (typically width of glass pane).
On the other hand, the maximum surface power dissipation permitted for a window pane is typically in the range 50 - 600 W/m2. Therefore, the maximum allowable input
power levels will be exceeded in a great number of cases for windows with normal dimensions if the window is directly connected to the mains voltage.
Accordingly, electrically heated glass pane elements are conventionally fed from the mains voltage either connect ed in series for a sufficiently high total resistance, o alternatively, having the glass pane elements connected to a lower voltage via a suitable transformer circuit. A novel type of heating power control is the time-switched input power feed control in which the mains voltage is applied in a time-limited manner, whereby a zero-power control cycle is inserted between the power-on control cycles.
Fault detection in heating systems based on continuous input power feed has not caused any major problem, because the occurrence of faults has been easy to monito by sensing the resistance of the power feed circuit. By contrast, no matter how cost-efficient the circuit may b otherwise, condition monitoring of a time-switched con¬ trol circuit is problematic as the power feed circuit is opened repetitively according to such a control scheme.
The goal of the invention is achieved by implementing th supply voltage feed to the fault-detection circuit by means of inductive coupling to the mains power feed con¬ ductor of the heated window pane so that said inductive coupling circuit is fed during the zero-power control cycles of the input power feed control period via an auxiliary power feed circuit connected in parallel with the terminals of the primary power switching circuit, whereby the auxiliary power feed is limited by means of series capacitor.
More speci ically, the method according to the invention is characterized by what is stated in the characterizing part of claim 1.
Furthermore, the fault-detection apparatus according to the invention is characterized by what is stated in the characterizing part of claim 5.
The invention offers significant benefits.
The arrangement according to the invention provides con¬ tinuous supply voltage to the fault-detection circuit independently from the input power feed control status, which may be active or nonactive. The system may addi- tionally serve as a burglary alarm. The system can be installed in a place concealed from unauthorized people, whereby a person possibly attempting a burglary or vandalism has no means of knowing whether the electric glass pane system is provided with an alarm facility or not. The present arrangement is suited for use in con¬ junction with all conventional input power controller types and the function of the apparatus is not dependent on the power-on control cycle duration or the power- on/power-off duty cycle. The components of the apparatus are inexpensive, and moreover, the apparatus can be made small due to the small number of components required.
In the following the invention will be examined in great¬ er detail with the help of an exemplifying embodiment by making reference to the appended drawings in which
Figure 1 is a block diagram of a circuit arrangement according to the invention;
Figure 2 is a circuit detail of the arrangement shown in Fig. 1; and
Figure 3 is a circuit diagram of an apparatus according to the invention complemented with a backup power supply circuit.
Referring to Fig. 1, the fault-detection arrangement shown therein is intended for use in an environment having at least one electrically heated glass pane 1 con¬ nected in series with a power feed conductor 2, whereby electric input power feed to the glass panes can occur through switching the power feed on and off by means of a switch 7. Single-phase feed is typically used as the supply 8 for window pane heating. According to the inven¬ tion, the apparatus is provided with toroidal transformer unit 13 with the feed conductor 2 threaded through the opening of its magnetic circuit 3. The fault-detection circuit 6 obtains its supply voltage either directly via a winding 5, whereby the energy induced by the conductor 2 in the toroidal magnetic circuit 3 is transferred via the winding 5 to the circuit 6. In this mode, the trans- former structure 13 acts as a current transformer. By contrast, when the switch 7 is opened and the heating power feed to the window panes 1 is turned off, an auxil¬ iary power feed circuit connected in parallel with the switch terminals 7 feeds energy via a winding 4 to the magnetic circuit 3 that further transfers the energy to the electric input power feed detecting circuit 6. Herein, the transformer structure 13 acts as a voltage transformer. In this manner the fault-detecting circuit 6 in its simplest form can sense the presence of electric energy invoked by alternating electromagnetic induction in the magnetic circuit 3. If no electric power feed is sensed, the detecting circuit issues an alarm signal. The capacitor 9 of the auxiliary power feed circuit is dimen¬ sioned so that the auxiliary power feed circuit will not cause excessive load in the system while yet supplying sufficient energy for the detecting circuit 6 to trigger the circuit. A suitable capacitance value of the
capacitor is, e.g., in the range of approx. 0.01 - 0.1 μF. In lieu of the toroidal magnetic circuit 3, any other suitable transformer core structure capable of inductively transferring the required sensing energy to the fault-detecting circuit 6 may be employed. A suitable triggering power level for the detecting circuitry is, e.g., in the range 200 - 500 m . The triggering power level is adjusted by varying the number of turns in the windings 4 and 5 as well as the number of turns of the conductor 2 wound about the core of the magnetic circuit 3. The following table gives typical guideline values for the different number of turns of the power feed conductor 2 for different current levels in the conductor.
Referring to Fig. 2, a typical fault-detection apparatus comprises a rectifier 10 followed by a low-pass filter, which in the present case is implemented as an RC circuit 11. A suitable time constant for the RC circuit 11 is, e.g., in the range 20 - 100 ms. The rectified, filtered sensing signal is in turn taken to a relay 12 arranged to open/close an alarm circuit at the loss of the sensing signal. Obviously, the relay 12 may be replaced by any digital sensing means based on solid-state devices.
Referring to Fig. 3, the circuit configuration of the apparatus is shown incorporating a backup power supply circuit. When the mains voltage (230 VAC) is switched on, the contactor K2 is energized thereby opening the con¬ tacts 21-22, 31-32 and 41-42. These contacts disconnect
the 12 V backup power supply circuit from the alarm cir- cuit(s). Simultaneously, the contact 15-14 is closed.
When the contact 15-14 of contactor K2 is closed, the contactor K3 is energized and contacts 21-22 and 31-32 open. These contacts give additional isolation in the disconnection of the backup power supply circuit. Con¬ tacts 23-24 and 15-14 are simultaneously closed, thereby switching the input power on to the electric heated glass pane system 1. Subsequently, the heating system which includes a thermostat for the electric glass pane and an alarm system commences operation in the same manner as the above-described electric glass pane system for burglary alarm.
With the mains feed switched on, the alarm relay Kl remains energized by the sensing voltage thus keeping the alarm circuit closed irrespective of whether the thermo¬ stat is open or close, provided that the electric glass pane circuit is intact.
Upon the disconnection of the mains supply, the contac¬ tors K2 and K3 release, whereby the electric glass pane system remains isolated from the mains on both the live and neutral ends of its feed circuit, and the backup power supply circuit is connected to feed the sensing circuit.
Now, the alarm relay Kl is connected to the positive potential of the backup power supply via its contact
K2:31-32 and to the ground potential of the backup power supply via the contacts K2:41-42 and K3:31-32 and the electric glass pane. The alarm relay Kl remains energized thus keeping the alarm circuit closed provided that the electric glass pane circuit is intact.
The purpose of the capacitor Cl is to prevent a direct short circuit over the voltage winding of the toroidal transformer Ml in the case that the mains supply is on while the thermostat contact is closed.
The purpose of the capacitor C2 is to block the DC path from the rectifier back to the toroidal transformer winding when the mains supply is disconnected.
The purpose of the capacitor C3 is to delay the release of the alarm relay Kl for the duration of contactor energization and thermostat contact switchover requiring a delay of less than one second typical.
The circuit 25 includes a mechanical antitamper switch serving to activate the alarm circuit if the enclosure of the apparatus is opened.
Elements 20 are fuses.
The invention is also suited for use in systems having the electric glass panes fed with a low-voltage supply via a transformer. Herein, the heating-power-controlling switch is typically located in the primary circuit of the step-down transformer.
The embodiment according to the present invention is particularly advantageously used in conjunction with a zero-voltage-switching power feed system in which each power-on cycle starts and stops at the zero-crossing point of sinusoidal AC supply voltage.
In the context of the present invention, the term magnet¬ ic circuit refers to any magnetic circuit suitable for use in a transformer such as a core made from a ferro¬ magnetic material.
Claims
1. A method for fault detection of electric glass panes in an electric glass pane system (1, 2, 7) operated with time-switched-type of input power feed control,
c h a r a c t e r i z e d in that
- the mains power feed conductor (2 ) of the electric window pane system (1) is adapted to pass through a transformer assembly (13) so that electric power is transferred to the magnetic circuit (3) of the transformer (13),
- the electric power level in the magnetic circuit
(3) of the transformer (13) is detected, and
- to the magnetic circuit (3) of the transformer (13) is additionally fed electric power via an auxiliary power feed circuit connected in parallel with the input feed power controlling switch (7), whereby the magnetic circuit (3) of the transformer (13) is kept energized at all times as long as all the panes ( 1 ) of the electric window pane system are intact.
2. A method as defined in claim 1, c h a r a c t e r ¬ i z e d in that the auxiliary power feed circuit is provided with a current-limiting capacitor (9).
3. A method as defined in claim 1 or 2, c h a r a c ¬ t e r i z e d in that the fault situation is detected by means of a relay (12) or a solid-state circuit.
4. A method as defined in claim 1, 2 or 3, c h a r ¬ a c t e r i z e d in that a backup power supply is connected to the circuit at the disconnection/outage of the mains supply.
5. An apparatus for fault detection of electric glass panes in an electric glass pane system (1, 2, 7) incor¬ porating a switching element (7) for time-switched input power feed control,
c h a r a c t e r i z e d in that said apparatus comprises
- a transformer assembly (13) having the mains power feed conductor (2) adapted to pass in the vicinity of said assembly so that electric power is transferred to the magnetic circuit (3) of the transformer (13),
- means (6 ) for detecting the electric power level in the magnetic circuit (3) of the transformer (13), and
- an auxiliary power feed circuit (4, 9) which is connected in parallel with said switching element (7) for the purpose of feeding electric power to the magnetic circuit (3) of the transformer (31) also when said switching element (7) is open, whereby the magnetic circuit (3) of the transformer is kept energized at all times as long as all the panes ( 1 ) of the electric window pane system are intact.
6. An apparatus as defined in claim 5, c h a r a c ¬ t e r i z e d in that said auxiliary power feed circuit includes a current-limiting capacitor (9).
7. An apparatus as defined in claim 5 or 6, c h a r ¬ a c t e r i z e d in that said fault-detection apparatus (6) includes a relay (12) suited for detecting a fault situation.
8. An apparatus as defined in claim 5, 6 or 7, c h a r a c t e r i z e d in that said fault-detection apparatus (6) incorporates a backup power supply for operation backup during mains disconnection/outage.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU47209/96A AU4720996A (en) | 1995-02-23 | 1996-02-23 | Fault-detection method and apparatus for electrically heated glass panes |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI950827A FI100016B (en) | 1995-02-23 | 1995-02-23 | Method and apparatus for detecting the occurrence of electric glass windows |
FI950827 | 1995-02-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996026449A1 true WO1996026449A1 (en) | 1996-08-29 |
Family
ID=8542915
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FI1996/000108 WO1996026449A1 (en) | 1995-02-23 | 1996-02-23 | Fault-detection method and apparatus for electrically heated glass panes |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU4720996A (en) |
FI (1) | FI100016B (en) |
WO (1) | WO1996026449A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2333627A (en) * | 1998-01-24 | 1999-07-28 | Brian Lawrence Birch | Security system for windows |
US7696644B2 (en) | 2007-02-06 | 2010-04-13 | Cooktek Llc | Wireless power transfer system for glass |
US8344296B2 (en) | 2007-10-10 | 2013-01-01 | Cooktek Induction Systems, Llc | Food warming device and system |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2072887A (en) * | 1980-03-24 | 1981-10-07 | Kenwood Mfg Co Ltd | Control of electrical heating elements |
US4583086A (en) * | 1982-04-08 | 1986-04-15 | Remote Sensors, Inc. | Circuit for monitoring the operating condition of an electric load |
-
1995
- 1995-02-23 FI FI950827A patent/FI100016B/en active
-
1996
- 1996-02-23 WO PCT/FI1996/000108 patent/WO1996026449A1/en active Application Filing
- 1996-02-23 AU AU47209/96A patent/AU4720996A/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2072887A (en) * | 1980-03-24 | 1981-10-07 | Kenwood Mfg Co Ltd | Control of electrical heating elements |
US4583086A (en) * | 1982-04-08 | 1986-04-15 | Remote Sensors, Inc. | Circuit for monitoring the operating condition of an electric load |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2333627A (en) * | 1998-01-24 | 1999-07-28 | Brian Lawrence Birch | Security system for windows |
GB2333627B (en) * | 1998-01-24 | 2002-07-17 | Brian Lawrence Birch | Security systems for windows |
US7696644B2 (en) | 2007-02-06 | 2010-04-13 | Cooktek Llc | Wireless power transfer system for glass |
US8344296B2 (en) | 2007-10-10 | 2013-01-01 | Cooktek Induction Systems, Llc | Food warming device and system |
Also Published As
Publication number | Publication date |
---|---|
FI950827A (en) | 1996-08-24 |
FI100016B (en) | 1997-08-15 |
AU4720996A (en) | 1996-09-11 |
FI950827A0 (en) | 1995-02-23 |
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