FI100016B - Method and apparatus for detecting the occurrence of electric glass windows - Google Patents

Description

100016

Method and apparatus for detecting electrical glass failure

The invention relates to a method according to the preamble of claim 1 for detecting the failure of electric glasses.

The invention also relates to an apparatus for detecting the failure of electric glasses.

10 The so-called Selective glass is also becoming more common in detached house applications. In these, the electrical power supplied to the conductive film can be used to raise the surface temperature of the glass to the desired value. The thickness of the conductive film must be very precise such that it transmits the wavelengths of visible light but on the other hand effectively reflects the heat radiation back indoors. In addition, for manufacturing reasons, only a few materials are suitable as the conductive film material. For this reason, the surface resistances Ra (square resistances) of the selective glasses are in the range of 15 to 20 Q Q and the typical value for the surface resistance is 19 Ω.

Thus, the resistance of one glass (k x 1) is given by the formula

Rusi ^ Ra ’where 25 k = distance between electrodes (eg height of glass) 1 = length of electrodes (eg width of glass)

On the other hand, the maximum surface power of glass is typically 50 to 600 W / m2. Thus, in very many cases, normal-window-30 work exceeds the maximum powers if the window is connected directly to the mains voltage.

Thus, according to the prior art, the glass elements to be heated are connected to the mains voltage either in series with a sufficiently high resistance 35 or the voltage is reduced to a suitable level by means of a transformer connection. A new solution for heating control is a time division control method in which the mains voltage is switched on in a time division manner, whereby there is a zero power period between the switching periods.

Fault detection in systems based on continuous power supply has not been a major problem because fault-5 can be controlled by the resistance of a closed power supply circuit. Instead, monitoring the condition of an otherwise inexpensive time-division control system is problematic because the power supply circuit is repeatedly opened during control.

The invention is based on the fact that the power supply of the fault detection system is carried out inductively from the power supply conductor of the window circuit, so that the inductive circuit is supplied at zero power periods of the control period by a side supply circuit connected in parallel with the circuit breakers.

More specifically, the method according to the invention is characterized by what is set forth in the characterizing part of claim 1.

20

The fault detection device according to the invention, in turn, is characterized by what is set forth in the characterizing part of claim 4.

The invention provides considerable advantages.

With the procedure according to the invention, the power supply to the monitoring circuit is continuous regardless of whether the power supply is on or not. The system also acts as a burglar alarm. 30 The system can be installed completely hidden from outsiders, so that it is impossible for a potential burglar or vandal to know if there is an alarm system in the glass system. The system is suitable for all types of controllers and the equipment is not dependent on switching time or pulse ratio. The price of the hardware components is affordable and the device can also be made small and the number of components low.

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3 100016

The invention will now be examined in more detail by means of an exemplary embodiment according to the accompanying drawings.

Figure 1 shows on a block diagram level an apparatus according to the invention.

Figure 2 shows a detail of the apparatus according to Figure 1.

According to Figure 1, the fault detection device is intended for use in an environment in which one or more electric glasses 1 are connected in series to the power supply line 2 so that the power is regulated by interrupting the supplied power with a switch 7. The power source 8 is typically a single phase voltage. According to the invention, the apparatus is provided with an annular transformer unit 13, through which the supply circuit 2 passes through the iron circuit 3. The fault detection device 6 receives its electrical energy either directly through the winding 5, whereby the power 20 induced by the conductor 2 in the annular iron circuit 3 is transferred through the winding 5 to the device 6. In this case, the transformer structure 13 acts as a current transformer. When the circuit breaker 7 opens and the power supply to the windows 1 is cut off, the side supply circuit connected in parallel with the terminals of the switch 7 supplies power to the iron circuit 3 via the winding 4, which in turn transfers electrical power to the earthing equipment 6. The transformer structure 13 acts as a voltage transformer. Thus, the detection apparatus 6, in its simplest form, detects the existence of electric power in the iron circuit 3 caused by a changing electromagnetic field. If there is no electric power to be detected, an alarm is given. The capacitor 9 of the side supply circuit is dimensioned so that the side supply circuit does not ·; overload the system but still provide sufficient energy to exceed the detection threshold of the detection device 6. A suitable value for the capacitor capacitance is, for example, about 0.01 to 0.1 μ F. Instead of the annular iron circuit 3 35, any transformer structure capable of inductively transferring the required powers to the detection equipment 6 can be used. A suitable power level for the detector is, for example, 200 to 500 mW. The power level is adjusted by the speeds of the windings 4 and 5 100016 4 and by the speeds of the power line 2 around the iron circuit 3. The following table shows typical values for power line 2 speeds at different power line current values.

5 Feedthrough rate Current range

1 10 - 40 A

2 5 - 20 A

4 2.5 - 10 A

10 10 1 - 4 A

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According to Figure 2, a typical detection apparatus comprises a rectifier 10 and a subsequently arranged low-pass filter 15, which in this case is implemented as an RC circuit 11.

A suitable time constant for the RC circuit 11 is, for example, 20 to 100 ms. * · The rectified, filtered signal is in turn fed to relay 12, which in the absence of a signal opens / closes the alarm circuit. Instead of relay 12, it is of course possible to use 20 digital indications based on semiconductor technology.

The invention is also applicable to solutions in which the voltage supplied to the glasses is reduced by a voltage transformer. The circuit breaker is then typically located in the primary of the voltage converter.

A particularly advantageous solution according to the invention is the so-called with a zero point controlled power supply system, where

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each power supply cycle begins and ends at the sinusoidal supply-30 voltage zero point.

In this application, iron circuit means any circuit suitable for a transformer, for example a transformer circuit made of ferromagnetic material.

Claims (6)

100016 A method for detecting the failure of electric windows in an electric glass system (1, 2, 7) in which the input power is adjusted in a time-divided manner, characterized in that - the power supply line (2) of the electric glass system (1) is arranged to pass through a transformer arrangement the power of the iron circuit (3) of the transformer (13) is detected, - the power of the iron circuit (3) of the transformer (13) is detected, and - the iron circuit (3) of the transformer (13) is further supplied via a side supply circuit connected to the circuit breaker (7), whereby the transformer (13) Electrical power is generated in the 20 iron circuits (3) whenever all the windows (1) of the system are in good condition. Method according to Claim 1, characterized in that a current-limiting capacitor (9) is arranged in the side supply circuit. Method according to Claim 1 or 2, characterized in that the fault condition is detected by means of a relay (12) 30 or a semiconductor circuit. »·« · An apparatus for detecting the failure of electric windows in an electric glass system (1, 2, 7) comprising a switching element (7) for adjusting the electric power to be applied periodically, characterized in that the apparatus comprises a transformer adapter (13) in the vicinity of which a power supply line (2) ) is adapted to travel so that electrical power is transferred to the iron circuit (3) of the transformer (13), 5 - detecting means (6) for detecting the power of the iron circuit (3) of the transformer (13), and - a side supply circuit (4, 9) connected to the - 10 parallel elements (7) for supplying power to the iron circuit (3) of the transformer (13) even when the coupling member (7) is open, whereby electrical power is generated in the iron circuit (3) of the transformer (31) whenever all windows of the window system (1) are okay. 15 Apparatus according to claim 4, characterized in that the side supply circuit comprises a current limiting capacitor (9). 20 Apparatus according to claim 1 or 2, characterized in that the detection device (6) comprises a relay (12) for detecting a fault condition. i · 100016