Device for remote blocking of electricity consumers. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Clocks, timers, relays, load switches

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Modern household powerful electrical appliances (electric kettles, microwave ovens, washing machines, heaters, vacuum cleaners), especially imported ones, are characterized by high current consumption. As a result of the simultaneous activation of several such devices, an overload of the electrical wiring can occur with unpleasant consequences.

The proposed device excludes the possibility of connecting the two most powerful consumers of electricity selected by the user (or two of their groups). One of them is more priority - the leader, the other - the slave. The master consumer can be enabled at any time, but the slave consumer can only be enabled when the master is disabled. For example, an electric kettle is a leading consumer, and a microwave oven is a slave. In this case, you cannot turn on the microwave oven while the electric kettle is heating the water.

Rice. 1 (click to enlarge)

The principle of operation of the device is based on the supply of a radio signal to turn off the power supply circuit of the slave consumer, while the current consumption of the master exceeds a certain threshold level. The basis of the device is a widely used remote doorbell in the 433 MHz band. Currently, such calls are widely used in amateur radio designs [1-3], including for power management [4]. The radio call has been modified and equipped with a control unit. To significantly reduce the "pollution" of the ether, pulsed radiation was used. The range of the radio call is several tens of meters, depending on the specific model and placement conditions, which is sufficient for the indicated purposes. The author used the "CONSTA NS-9688C" radio call.

The proposed device consists of radio transmitting and radio receiving parts. The first is used on the side of the leading load, the second - on the side of the slave. On fig. 1 shows a diagram of the bell transmitter control unit. Current transformer T1 is a current sensor in the power supply circuit of the leading load. The use of this transformer makes it easy to implement the galvanic isolation of the sensor [5-8].

The voltage from the secondary winding of the current transformer (about 50 mV at a load current of 10 A) passes through the isolation capacitor C1 to the first amplifying stage on the DD1.1 element. Capacitor C2 suppresses high-frequency interference and impulse noise at the input (pin 1) of element DD1.1. The use of a logic element as a linear amplifier is caused by the desire to make full use of the elements of the DD1 chip [9].

The "XOR" element of the K564LP2 microcircuit, similarly to the elements of other microcircuits of the CMOS structure, is capable of operating in a linear mode as an amplifier. But for this it is necessary to apply a high level to one of its inputs, thereby turning it into an inverter, and include the second input in the OOS circuit. The gain of elements of this type without feedback is small - only 25 ... 30 at a frequency of 50 Hz. However, this is enough.

The signal amplified by the DD1.1 element through the capacitor C3 is fed to the DD1.2 element. Both elements are covered by local OOS circuits and at a frequency of 50 Hz have a gain of 10...12 each. The signal from the output of the element DD1.2 through the capacitor C4 is supplied to the shaper of rectangular pulses, collected on the element DD1.3. The internal diode, connected by the cathode to terminal 8, and the anode to the common wire of the DD1 microcircuit, opens during negative polarity pulses and closes during positive polarity pulses, thereby detecting an amplified signal.

If the signal at the input (pin 8) of the element DD1.3 is below the switching threshold, the output of this element is high, the transistor VT1 is closed, otherwise the transistor VT1 opens with a network frequency of 50 Hz. Resistor R8 limits the pulse current of the collector of transistor VT1 at a safe level. Capacitor C5 is charged, causing it to generate a high level DC voltage for as long as the driving load is on.

This voltage is supplied to a single vibrator on the DD1.4 element, at the output of which a high-level pulse with a duration of 0,7R10C6 (about 1 s) is formed, which is quite enough for a stable operation of the switching part. The second pulse of the same duration is formed when the leading load is turned off. Transistor VT2 opens during these pulses, as a result of which the supply voltage is supplied to the ringer transmitter, which consumes a current of several milliamps. Diode VD1 limits the reverse voltage at the emitter junction of transistor VT2 at a safe level.

The transmitter control unit is powered by a GB1 battery of size 23A with a voltage of 12 V of the radio call transmitter unit. Instead of a battery, it is better to use a mains power supply with a stabilized output voltage of 12 V.

The output of the control unit is connected to the power circuits of the bell radio transmitter, which has not been modified. SB1 - call button - left for the possibility of manual remote control of the slave consumer of electricity. Capacitors C7 and C8 are installed in the transmitter unit of the radio call. They smooth out the pulses of current consumed by the transmitter, preventing them from affecting the control unit.

The receiving part of the device consists of a modified radio call receiver and a switching unit, the diagram of which is shown in Fig. 2. The unit consists of a pulse shaper based on a transistor VT1, a D-trigger DD1.1, switching transistors VT2 and VT3, an optoelectronic AC switch on a triac optocoupler U1, a powerful triac VS1, resistors

Rice. 2 (click to enlarge)

R3-R5 and capacitor C3. The radio receiver is being finalized like this. Elements of a transformerless power supply are removed from its printed circuit board, except for VD5-VD8, HL3, C6, C7. A new power supply is installed in the vacated space: transformer T1, diode bridge VD1-VD4, smoothing capacitor C5, resistors R8 and R9. Then the printed conductor is cut, suitable for terminal 9 of the TS4069 microcircuit, a capacitor C8 is installed between this terminal and the common wire, and a resistor R10 is soldered into the conductor cut (shown by the "x" sign). The output of the radio receiver - pin 8 of the TC4069 chip is connected to the input of the switching unit. Despite the fact that the TC4069 chip is produced in different packages, the number of pins and their numbering are the same.

The output voltage of the new power supply 12 ... 15 V is supplied to the LEDs HL1 and HL2 through the current-limiting resistor R8. Chip DD1 and transistor VT1 are powered by a parametric voltage regulator, consisting of a resistor R9 and VD5-VD8HL3 elements left over from the dismantled transformerless network power supply of the radio call. The HL3 LED is also used as an indicator of the presence of mains voltage and the health of the power supply. The radio call used by the author uses the RD314S LED (HL3 in Fig. 2), and the VD5-VD8 circuit contains four diodes. In some other radio calls, there may be a circuit of two or three diodes connected in series, in which case the voltage of the parametric stabilizer may be in the range of 3,3 ... 4,5 V. This voltage feeds the VT1 transistor and the DD1 microcircuit. Its unused inputs are connected to a common wire.

After the supply voltage is applied, the elements C4, R6, R7 generate a pulse that sets the trigger DD1.1 to a low state at pin 1. The transistor VT2 is closed, the HL1 LED is off. The transistor VT3 is open, its drain current flows through the emitting diode of the optocoupler U1.2, as a result of which the optosimistor U1.1 and the triac VS1 are open. The driven load connected to the output of the device can be connected to the network, which is indicated by the burning LED HL2.

When the driving load is turned on, a low-level pulse from the output of the radio receiver through the R1C1 circuit enters the gate of the transistor VT1, as a result of which this transistor closes. The R1C1 circuit and a similar circuit added to the receiver, as mentioned above, prevent false alarms from interference. A high-level pulse from the drain VT1 is fed to the input C of the trigger DD1.1 and switches it. Transistor VT2 opens and VT3 closes. LED HL2 goes out. Optotriac U1.1 and triac VS1 close. In this case, the driven load is de-energized, as indicated by the on LED HL1. If necessary, the state of the device can be reversed by manually pressing the radio call button SB1.

The current transformer T1 (see Fig. 1) is made on the basis of the relay coil RES10 (version RS4.529.031 -05), which is used as a secondary winding (II). You can also use the relay versions RS4.529.031-12 and RS4.529.031-20. The size of the coil allows you to place it directly in the power outlet of a powerful consumer of electricity. The winding contains 1100 turns, its resistance is 45 ohms. The primary winding (I) is wound on it from two turns of insulated wire with a cross section of 2,5 mm2. Such a current transformer provides a voltage of 50 mV at a resistance of 47 ohms at a load current of 10 A. If the load current exceeds 25 A, the number of turns of the primary winding can be reduced to one.

The device can use transformers on ferromagnetic annular magnetic circuits, the designs of which are described in [5-7]. During manufacture, the current transformation ratio should be taken within 1:300 ... 1:1000. It is also possible to use commercially manufactured current transformers, for example, for electricity meters [8].

Fig. 3

The transformer current sensor can be replaced with a resistor one, as shown in the diagram in Fig. 3. Optocoupler U1 provides galvanic isolation of the bell transmitter control unit from the mains voltage. A current sensor is included in the break of the phase wire of the load - a powerful resistor R1, the voltage from which, proportional to the load current, is connected through the current-limiting resistor R2 to the emitting diode U1.

Diode VD1 limits the reverse voltage on the emitting diode of the optocoupler. The phototransistor of the optocoupler U1 is switched on instead of the transistor VT1 (see Fig. 1), taking into account the fact that these transistors have different structures. The collector of the phototransistor of the optocoupler U1 is connected to the plus of the power source, and the emitter is connected to the upper (according to the diagram) terminal of the resistor R8. Transistor VT1, resistor R7 and all components located in fig. 1 to the left, do not use. The advantage of a resistor current sensor is a smaller number of parts and the absence of winding elements, the disadvantage is the presence of a powerful heat-generating resistor.

Fig. 4

The control unit is placed in the body of the bell transmitter above its printed circuit board, as shown in fig. 4. Transistor VT1 can be with any letter index from the KT361 or KT3107 series. Transistors VT2 - any of the KT3102 series. Diode VD1 - any of the KD509, KD510, KD521, KD522 series. Capacitors C2, C4, C8 - any film or ceramic, the rest - imported oxide.

Fig. 5

The receiving and switching unit of the device (see fig. 2) is placed in a unified plastic case for power devices with external dimensions of 120x120x75 mm, as shown in fig. 5. The boards of the radio receiver and the switching unit are attached to the case with M1 screws and connected to each other by wires. Holes are drilled for HL3-HL1 LEDs. A powerful triac VSXNUMX is installed on a heat sink from the Pentium I processor.

In the receiving and switching unit (see Fig. 2), the K561TM2 (DD1) microcircuit can be replaced with KR1561TM2, all transistors from the KP501 series with any letter index. Triac optocoupler MOS3083M (U1) can be replaced by MOS3081M, MOS3082M, MOS3051, MOS3052. Triac BTA139-800 (VS1) with a maximum load current of 16 A can be replaced with BTA139-600, and if the load current is more than 16 A, but less than 25 A, with BTA140-800 or BTA140-600. Capacitor C3 - K73-17 with a rated voltage of 630 V. The yellow AL307EM (HL1) LED can be replaced with AL307ZhM. This LED indicates the prohibition of turning on the driven load, so it can be red AL307BM or AL307KM. LED AL307GM (HL2) of green glow indicates the possibility of switching on the driven load, it can be replaced by AL307VM. The VD5-VD8HL3 circuit can be replaced with a zener diode from the KS133-KS147 series with any letter index, the cathode of which is connected to the right (according to the diagram) output of the resistor R9, and the anode to the negative power wire.

The mains transformer of the power supply T1 is any with a rated power of 3 ... 4 W and a secondary winding voltage of 9 ... 11 V. Such transformers are often used in household radio equipment. A self-made power supply T1VD1-VD4C5 can be replaced with a ready-made network adapter with an output voltage of 12 ... 15 V and a current of at least 30 mA.

Setting up the device comes down to setting the threshold for the operation of the transmitter control unit (see Fig. 1) from the current consumed by the leading load. In the process of establishing, the number of turns of the primary winding (I) of the current transformer T1 is selected, and the necessary gain of the elements DD1.1 and DD1.2 is also set by a selection of resistors R3 and R5 within 300 ... 1000 kOhm. The switching unit (see Fig. 2) does not require adjustment.

Literature

1. Nechaev I. Security device based on a wireless call. - Radio, 2011, No. 9, p. 53, 54.
2. Nechaev I. Leak detector based on radio call. - Radio, 2011, No. 3, p. 53, 54.
3. Nechaev I. Security device based on radio call. - Radio, 2007, No. 9, p. 59, 60.
4. Nechaev I. Remote power switch. - Radio, 2011, No. 7, p. 42, 43.
5. Nechaev I. Power consumption indicator. - Radio, 1986, No. 2, p. 49, 50.
6. Nechaev I. Power consumption indicator. - Radio, 2000, No. 11, p. 59.
7. Evseev A. The use of a power-frequency converter of the KR1095PP1 series in electronic devices. - Radio, 2008, No. 10, p. 28-31.
8. Kosenko S. Active power meter based on the ADE7755 chip. - Radio, 2010, No. 8, p. 19, 20.
9. Voskoboynikov M. Digital microcircuits in LF devices. - Radio, 1981, No. 7/8, p. 37.

Author: D. Pankratiev

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