All about the washing machine wash timer. Refrigerator delay timer Delay timer

The operating instructions for some household refrigerators, for example, STINOL, say that they can be reconnected to the network no earlier than 4...5 minutes after being disconnected. This time is necessary for condensation and a decrease in refrigerant pressure. Otherwise, the starting load on the compressor motor is too high, which causes overheating of its windings. It is in this situation that engine failure is most likely.

It is impossible to fulfill this requirement without the use of additional protection devices. The household refrigerator is on 24 hours a day. To disable it, even a short-term power outage, which is common for our electrical networks, is enough, especially at night or when the owners are absent. In such cases, it is necessary to automatically delay turning on the refrigerator for approximately 5 minutes after the mains voltage is restored. This function can be performed by a timer, the diagram of which is shown in Fig. 1.

It works like this. At the first moment after the mains voltage is applied, capacitor C3 is discharged and its charging begins through resistor R3. Logic element DD1.1 serves as a threshold device. While the voltage at its inputs is below the switching threshold, its output is high, and the output of element DD1.2 is a low logic level. Transistor VT1 is closed, there is no current in its emitter circuit. Therefore, the thyristors of optocouplers U1 and U2, and with them the triac VS1, are closed. The refrigerator's power supply circuit is open.

After approximately 5 minutes, the voltage on capacitor C3 will reach a level at which the state of elements DD1.1, DD1.2 will change and transistor VT1 will open. Thanks to positive feedback through resistors R4 and R5, this process develops like an avalanche, the current through the LEDs of optocouplers U1, U2 increases abruptly. As a result, the photothyristors of the optocouplers open alternately at the beginning of each half-cycle of the mains voltage, and the current flowing through them and resistor R6 opens the triac VS1. The refrigerator is connected to the network.

If the mains voltage disappears for more than 1...2 s, capacitors C2 and C3 will have time to discharge (the latter through diode VD6). Resistor R2 serves to speed up the discharge process. When voltage appears, the process described above will be repeated and the refrigerator will be turned on only after 5 minutes.

The timer power supply unit is assembled according to a transformerless circuit with a quenching capacitor C1. Resistor R1 limits the inrush current when turned on. The voltage rectified by the diode bridge VD1-VD4 is stabilized using the HL1 LED and VD5 zener diode connected in series. The glow of the LED is a sign of the presence of voltage in the network.

The timer is assembled in a housing from a BP2-3 power supply (the so-called network adapter), which was supplied with some microcalculators. The socket for connecting the refrigerator is mounted on the body of the unit on the side opposite the power plug, and inside the case there is a printed circuit board made of foil fiberglass, shown in Fig. 2.

The K561LE5 microcircuit can be replaced with a K561LA7 without any circuit adjustments. Transistor VT1 - series KT312, KT315 with any letter indices. Suitable low-power diodes with a permissible rectified current of at least 30 mA are suitable for VD1-VD4, and a replacement for VD6 should be chosen with a low reverse current, for example, KD102B, KD104A. LED HL1 - any color with a maximum current of 30 mA. The forward voltage drop on different types of LEDs can differ by 1 ... 2 V, which should be taken into account when choosing a VD5 zener diode. The total voltage on the zener diode and LED should not exceed 10...15 V.

Capacitor C1 - K73-17, C2 - any oxide, C3 - oxide with low leakage current, for example, K52 series. All resistors are MLT or C2-33 with the power indicated on the diagram. The VS1 triac (its voltage class must be at least 4) is equipped with an aluminum heat sink with an area of ​​several square centimeters and is attached to the board, for example, with epoxy glue.

Setting up a timer comes down to setting the required response delay by selecting resistor R3. It should be taken into account that an excessive increase in the resistance of this resistor leads to delay variability caused by the influence of leakage currents from capacitor C3 and between the conductors of the printed circuit board. The leakage current of an oxide capacitor that has not been energized for a long time is usually increased. Therefore, be sure to check the delay after the timer has been running continuously for at least a day, and if necessary, set it again.

A timer similar in purpose and principle of operation can be assembled according to the diagram shown in Fig. 3.

Its main difference is that the load (refrigerator) is switched not with a triac, but with the help of relay K1. The trigger, which switches when the voltage on capacitor C2 reaches a threshold level, is formed in this case by elements DD1.1 and DD1.4. Parallel connected elements DD1.2, DD1.3 are a buffer cascade that controls an electronic switch on transistor VT1, the collector circuit of which includes relay winding K1. Resistor R5 is needed to speed up the discharge of capacitors after turning off the mains voltage. The current flowing through it is not enough to keep relay K1 in the activated state. Transformer T1, diode bridge VD1 and capacitor C1 are the timer power supply unit.

LEDs HL1 and HL2 serve to indicate the presence of voltage in the network and the status of the timer. If none of them is lit, there is no voltage in the network. From the moment voltage appears until the refrigerator turns on, the HL1 LED lights up. Then it goes out and the HL2 LED lights up.

When selecting a relay, it should be taken into account that its contacts must be designed to switch a current of several amperes consumed by the refrigerator in starting mode. The author's version of the timer uses the REN-18 relay, passport RX4.564.706. Transformer T1 - with a voltage on the secondary winding of 6 V at a load current of 300 mA. The rectified voltage on capacitor C1 was 7...8 V. If there is a relay with a high operating voltage, the voltage on the secondary winding of the transformer should be increased accordingly. However, when the rectified voltage increases above 15 V, the DD1 microcircuit should be powered through a simple stabilizer with an output voltage no more than specified. Be sure to shunt the output of the stabilizer with a 1 kOhm resistor, which creates a discharge circuit for capacitor C2.

The time delay relay is designed to adjust the operating sequence of certain elements of the electrical circuit. Basically, such devices are used in devices that require automatic execution of a certain action after a set period of time.

General information about the device

A relay is a device that works on the battery principle. The duration of the working mechanism can be daily, weekly, or hourly. These devices are installed where control of circuits that have low power is needed. In this case, complete isolation occurs between the control and controlled conductors. The relay is designed to control several circuits simultaneously using one signal.

Initially, relays were used in long-distance telephone circuits. They served a function amplifier: they duplicated the signal from one circuit to another and transmitted it in a chain reaction. Relays worked in early computers, executing simple commands in logical circuits.

What is a relay used for? electromagnetic field? It is a shock absorber that slows down or completely cuts off the movement when the coil suddenly enters a voltage environment. It is this property that makes it possible for the relay to delay time: the time for connecting the armature to the voltage coil slows down.

Several options for such devices

Using a time relay makes it possible to save on energy consumption, since the light will turn on and off automatically after a set period of time.

How does a time delay relay work?

Due to the fact that electric current creates a magnetic field with the help of conductors, the current state of the relay reacts with inductors to all changes. Locations of the magnetic field will depend on the shape of the conductor. If it is made at a right angle, then the field will be located in the same way; if it is in the form of a coil, then the magnetic field will be located along its entire length. The strength of the magnetic field directly depends on the current voltage.

Relays have become popular because they have proven their effectiveness when used. They can control large and small voltages. The relay coil is capable of passing fractions of watts through itself, while the contacts conduct hundreds of watts of load energy.

The principle of operation of the relay resembles binary amplifier on and off. As practice shows, one relay coil can actuate several contacts of one device. These can be contacts of any combination. The device works with contacts of any type: mercury, metal, magnetic reeds.

What does a delay relay consist of?

If the device is a simple two-channel electromagnetic relay, then it includes:

The anchor is attached by hinges to the yoke and mechanically connected by one or more sets of contacts. The anchor itself is held in place by a spring. It is installed in such a way that during the absence of current, a air gap. In this mode of the device, one of the contacts is in the closed position, the other is in the open position. Some types of devices have a larger number of contacts, it all depends on the functions provided.

When an electric current is supplied, a magnetic field is generated, which makes it possible to activate the armature with the subsequent movement of the movable contact. This allows you to make breaks or connections with fixed contacts. When the contacts are open, the contacts are connected and closed; when the contacts are turned off, the opposite occurs. When the current is turned off, the armature takes its original position and returns under the influence of a force that is several times less than the magnetic one, so its position is normally relaxed. Most often, this force is provided by a spring; gravity is used only in industrial installations.

When current is applied to the coil, the diode passes through it and dissipates energy from the decaying magnetic field during decontamination. If this process does not start, the components of the circuit will receive an energy surge, which will lead to their failure.

DIY delay relay

To create a relay with a turn-off delay of 220 V, you do not need any special electromechanical knowledge; it will be enough to have basic knowledge of physics and electromechanics. Exists definite guidance, which will help you assemble the relay yourself.

For a time relay, it is considered optimal using transistor circuits. Such relays are great for monitoring the operation of wipers on a car, turning on and off lights on the street, washing machine. Delayed activation of the 220V relay is an excellent option that combines household conveniences and excellent savings.

The 555 series chip was developed quite a long time ago, but still remains relevant. Several dozen different devices can be assembled on the basis of a chip with a minimum number of additional components in the circuit. The simplicity of calculating the values ​​of components of the microcircuit body kit is also its important advantage.

This article will discuss two options for using a microcircuit in a time relay circuit with:

• Turn-on delay;
• Shutdown delay.

In both cases, the 555 chip will function as a timer.

How does the 555 chip work?

Before moving on to the example of a relay device, let's consider the structure of the microcircuit. All further descriptions will be made for the series microcircuit NE555 manufactured by Texas Instruments.

As can be seen from the figure, the basis is RS flip-flop with inverse output, controlled by outputs from comparators. The positive input of the upper comparator is called THRESHOLD, negative input of the lower - TRIGGER. Other comparator inputs are connected to a supply voltage divider consisting of three 5 kOhm resistors.

As you most likely know, an RS flip-flop can be in a steady state (it has a memory effect of 1 bit) either in a logical “0” or in a logical “1”. How it works:

• R (RESET) sets the output to logical "1"(precisely “1”, not “0”, since the trigger is inverse - this is indicated by the circle at the output of the trigger);
• Arrival of a positive impulse at the input S (SET) sets the output to logical "0".

Three 5 kOhm resistors divide the supply voltage by 3, which leads to the fact that the reference voltage of the upper comparator (the “–” input of the comparator, also known as the CONTROL VOLTAGE input of the microcircuit) is 2/3 Vcc. The lower reference voltage is 1/3 Vcc.

With this in mind, it is possible to create tables of states of the microcircuit relative to the inputs TRIGGER, THRESHOLD and exit OUT. Note that the OUT output is the inverted signal from the RS flip-flop.

Using this functionality of the microcircuit, you can easily make various signal generators with a generation frequency independent of the supply voltage.

In our case, to create a time relay, the following trick is used: the TRIGGER and THRESHOLD inputs are combined together and a signal is supplied to them from the RC chain. The state table in this case will look like this:

The NE555 connection diagram for this case is as follows:

After power is applied, the capacitor begins to charge, which leads to a gradual increase in the voltage across the capacitor from 0V onwards. In turn, the voltage at the TRIGGER and THRESHOLD inputs will, on the contrary, decrease, starting from Vcc+. As can be seen from the state table, there is a logical “0” at the OUT output after Vcc+ is applied, and the OUT output switches to a logical “1” when the voltage at the indicated TRIGGER and THRESHOLD inputs drops below 1/3 Vcc.

The important fact is that relay delay time, that is, the time interval between applying power and charging the capacitor until the OUT output switches to logical “1”, can be calculated using a very simple formula:

T = 1.1 * R * C
And as you can see, this time does not depend on the supply voltage. Consequently, when designing a time relay circuit, you don’t have to worry about power stability, which significantly simplifies the circuit design.

It is also worth mentioning that in addition to the 555 series, episode 556 in a 14-pin package. The 556 series contains two 555 timers.

Device with delay function

Let's move directly to the time relay. In this article we will analyze, on the one hand, a circuit that is as simple as possible, but on the other hand, it does not have galvanic isolation.

Attention! Assembly and adjustment of the circuit in question without galvanic isolation should be performed only by specialists with the appropriate education and approvals. The device is dangerous because it contains dangerous voltage.

Such a device in its design has 15 elements and is divided into two parts:

1. Supply voltage generation unit or power supply unit;
2. Node with temporary controller.

The power supply operates on a transformerless principle. Its design includes components R1, C1, VD1, VD2, C3 and VD3. The 12 V supply voltage itself is formed on the zener diode VD3 and smoothed by capacitor C3.

The second part of the circuit includes an integrated timer with a fitting. We described the role of capacitor C4 and resistor R2 above, and now, using the previously stated formula, we can calculate the value of the relay delay time:

T = 1.1 * R2 * C4 = 1.1 * 680000 * 0.0001 = 75 seconds ≈ 1.5 minutes By changing the values ​​of R2-C4, you can independently determine the delay time you need and remake the circuit yourself for any time interval.

The operating principle of the circuit is as follows. After the device is connected to the network and the supply voltage appears on the zener diode VD3, and, consequently, on the NE555 chip, the capacitor begins to charge until the voltage at inputs 2 and 6 of the NE555 chip drops below 1/3 of the supply, that is, to approximately 4 V. After this event occurs, a control voltage will appear at the OUT output, which will start (turn on) relay K1. The relay, in turn, will close the load HL1.

Diode VD4 accelerates the discharge of capacitor C4 after turning off the power so that after quickly reconnecting the device to the network, the response time is not reduced. Diode VD5 dampens the inductive surge from K1, thereby protecting the circuit. C2 is used to filter interference from the NE555 power supply.

If the parts are selected correctly and the elements are installed without errors, then the device does not need to be configured.

When testing the circuit, in order not to wait a minute and a half, it is necessary to reduce the resistance R1 to a value of 68–100 kOhm.

You probably noticed that there is no transistor in the circuit that would turn on relay K1. This was done not out of economy, but because of the sufficient reliability of output 3 (OUT) of the DD1 chip. The NE555 microcircuit can withstand a maximum load of up to ±225 mA at the OUT output.

This scheme is ideal to control the operating time of ventilation devices installed in bathrooms and other utility rooms. Due to its presence fans turn on only if they are present in the room for a long time. This regime significantly reduces electrical energy consumption and extends the service life of fans due to less wear of rubbing parts.

How to make a relay with a switch-off delay

The above circuit, thanks to the features of the NE555, can be easily converted into a shutdown delay timer. To do this, you need to swap C4 and R2-VD4. In this case, K1 will close the load HL1 immediately after turning on the device. The load will be turned off after the voltage on capacitor C4 increases to 2/3 of the supply voltage, that is, to approximately 8 V.

The disadvantage of this modification is the fact that after disconnecting the load, the circuit will remain exposed to dangerous voltage. This drawback can be eliminated by connecting a relay contact to the power supply circuit to the timer in parallel with the power button ( just a button, not a switch!).

The diagram of such a device, taking into account all the modifications, is shown below:

Attention! In order for dangerous voltage to actually be removed from the circuit by the relay contact, it is necessary that the PHASE be connected exactly as shown in the diagram.

Please note that the 555 timer is used and described on our website in another article in which it is discussed. The circuit presented there is more reliable, contains galvanic isolation and allows you to change the time delay interval using a regulator.

If you need a printed circuit board drawing when making a product, write about it in the comments.

Video on the topic

Indicators

Indicators inform the user of important

intelligence. Indicator meaning:

Delay timer

If the Delay Timer function has been enabled

(see “Personalized settings”), after

when the program starts, the indicator will start flashing,

corresponding to the specified delay time:

As the time counts down, it will show

remaining time along with flashing
the corresponding indicator.

x.\\I //.

After the specified delay time has passed
The flashing indicator will go out and the specified program will start.

program.

Indicators of the current phase of the cycle:
After selecting and starting a wash cycle, the indicators

will light up one after another, indicating
sequence of program execution:

Rinsing

End of the cycle

L" I /\\

Additional function buttons and

relevant indicators

When a function is selected, the corresponding one lights up

If the selected function is not compatible with

given program, the corresponding indicator

will blink and this function will not be enabled.

If you select a function that is not compatible with

the other previously selected function will remain

Only the last selected function is enabled.

Hatch lock indicator:

When the indicator is on, the sunroof is

locked to prevent accidental

opening. To avoid damaging it
you need to wait until the indicator goes out,
before opening the hatch.

START/PAUSE indicator flashes quickly
(orange) simultaneously with the function indicator
means deviation from normal operation (cm.

""Faults and methods for eliminating them").

How to start the program

1. Turn on the machine using the ON/OFF button. All indicators will light up for a few seconds, then

The settings indicators for the selected program will remain on and the START/PAUSE indicator will flash.

2. Load laundry into the drum and close the door.

3. Use the PROGRAM knob to set the desired program.

4. Set the wash temperature (See “Personalized Settings”).

5. Set the spin speed (See “Personalized Settings”).

6. Place detergents and additives (See “Laundry detergents and types of laundry”).

7. Enable additional features you want.

8. Start the program using the START/PAUSE button, the corresponding indicator will turn green.
To cancel a set cycle, switch the machine to pause mode using the START/PAUSE button and select a new one

9. At the end of the program, the END indicator will light up. The DOOR LOCK indicator will go out to indicate that
Now you can open the hatch. Remove the laundry and leave the door half-open to dry the drum.

Turn off the washing machine by pressing the ON/OFF button.