Prefix for charger on an electromagnetic relay. Electronic Battery Charging Signaling

This prefix, the diagram of which is shown in the figure, is made on a powerful compound transistor and is designed to charge the automotive rechargeable battery Voltage 12 in variable asymmetric current. It provides automatic battery training, which reduces its tendency to sulfate and extends the service life. The prefix can work together with almost any double-speaker pulse charger, providing the necessary charging current, for example, with industrial dawn-2.

When connecting the exit of the prefixtakes with the battery (the charger is not connected) when the C1 condenser is still discharged, starts to flow the initial charging current of the capacitor through the resistor R1, the emitter transition transistor VT1 and the R2 resistor. The VT1 transistor opens, and a significant discharge current of the battery flows through it, a quickly charging capacitor C1. With increasing voltage on the condenser, the battery discharge current decreases almost to zero.

After connecting the charger to the input of the console, the battery charging current appears, as well as a small current through the R1 resistor and the VD1 diode. At the same time, the VT1 transistor is closed, since the voltage drops on open diode VD1 is not enough to open the transistor. The VD3 diode is also closed, since the reverse voltage of the charged condenser C1 is applied to it through the VD2 diode.

At the beginning of the half-period, the output voltage of the charger folds with a voltage on the condenser, and the charging of the battery occurs through the VD2 diode, which leads to the return of energy accumulated by the capacitor, into the battery. Next, the capacitor is completely discharged and the VD3 diode opens through which the battery is now continuing. Reducing the output voltage of the charger at the end of a half-period to the level of the EDC of the battery and below leads to a change in the voltage polarity on the VD3 diode, its closure and discontinuation of the charging current.

At the same time, the transistor VT1 reopened and a new battery discharge pulse and a capacitor charge occurs. With the beginning of the new half-period of the output voltage of the charger, the next battery charging cycle begins.

The amplitude and duration of the discharge pulse of the battery depend on the R2 resistor ratings and C1 condenser. They are chosen in accordance with the recommendations given in [L].

The transistor and diodes are placed on separate heat sinks of at least 120 cm 2 each. In the console, the K50-15 capacitor is applied to the maximum allowable operating temperature +125 ° C; It can be replaced by the capacitors of large sizes on the rated voltage of at least 160 V, for example, K50-22, K50-27 or K50-7 (500 μF capacity). Resistor R1 -LT-0.5, A R2 - C5-15 or made independently.

In addition to the CT827 A transistor specified on the scheme, KT827B, KT827B, can be used. In the console, CT825G transistors - KT825E and KD206A diodes can be applied, but at the same time the polarity of the diodes, the capacitor, as well as the input and output clamps of the console, should be changed to the opposite.

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We present a simple scheme of the console machine for a car charger. Simple industrial and homemade memory for auto accumulators is recommended to supplement this machine, which includes it when it decreases the voltage on the battery to the minimum permissible value and disconnecting after complete charging. Especially since not every budgetary has such functions.
Electrical circuit

Maximum voltage for car batteries It is the value of 14.2 ... 14.5 V, the minimum allowable - 10.8 V. The minimum is desirable to limit for greater reliability of 11.5 ... 12 V. Scheme work. After connecting the battery and turn on the network, the SB1 "Start" button is pressed. Transistors VT1 and VT2 are closed, opening the key VT3, VT4, including the K1 relay. It is properly closed contacts to K1.2 with its normally closed contacts, which is normalized by the relay of which (K2.1), closed, plug in the charger to the network. Such complex scheme Switching is used for two reasons: firstly, the disconnection of the high-voltage chain from low-voltage; Secondly, the K2 relay turned on with the maximum voltage of the AB and disconnected with the minimum. Contacts K1.1 Relay K1 are shifted to the lower position. In the process of charging AB, the voltage on the resistors R1 and R2 increases, and when the unlocking voltage is reached on the VT1 database, the VT1 and VT2 transistors open, closing the key VT3, VT4.

The K1 relay is turned off, including K2. Normally closed contacts K2.1 are opened and de-energized the charger. Contacts K1.1 go to the upper position. Now the voltage on the basis of the composite transistor VT1, VT2 is determined by the voltage drop on the resistors R1 and R2. As the abey is discharged, the VT1 database is reduced, and at some point VT1, VT2 is closed, opening the key VT3, VT4. The charging cycle begins again. Conduator C1 serves to eliminate interference from the rattles of contacts K1.1 at the time of switching.

Setting the console to the charger
Adjustment is carried out without a battery and charger. Need adjustable bp constant voltage With the limits of the smooth adjustment, it is connected to the conclusions of the circuit instead of GB1. The R1 resistor engine is transferred to the upper position, and the R5 engine is at the bottom. The source voltage is set equal to the minimum battery voltage (11.5 ... 12 V). Moving the R5 engine is to turn on the relay K1 and the VD7 LED. Then, lifting the source voltage to 14.2 ... 14.5 V, the movement of the engine R1 reaches the disconnection of K1 and the LED. By changing the source voltage in both directions, it is convinced that the inclusion of the device occurs at a voltage of 11.5 ... 12 V, and shutdown - at 14.2 ... 14.5 V. Setting is ready - you can conduct tests. Only the first charging must be controlled by being nearby.

The ready-made device can be placed in the charging housing (if the place allows), and can be in the form of a separate unit.

Section:

Completion of the available automatic charger for the automotive battery at your disposal, you can be calm for the battery charging mode - as soon as the voltage at its outputs reaches 14.5 ± 0.2 V, the charging will stop. When the voltage is reduced to 12.8 ÷ 13, the charging will resume.

The prefix can be made in the form of a separate block or built into the charger. In any case, a prerequisite for its operation will be a pulsating voltage at the output of the charger. Such a voltage is obtained, say, when installing in the device of a two-speech rectifier without a smoothing capacitor.

Machine console scheme For charger shown in Fig. 2.91. It consists of a thyristor VS1, a thyristor control node, a switch of the SA1 machine and two indication circuits - on the HL1 and HL2 LEDs. The first chain indicates charging mode, the second - controls the reliability of connecting the battery to the clips of the console machine. If there is in the charger emergency indicator - Ampmeter, the first chain of the indication is not required.

Fig. 2.91. Concept of the console machine for charger.

The control node contains a trigger on the VT2 transistors, VT3 and the current amplifier on the VT1 transistor. The base of the transistor VT3 is connected to the engine of the trigger resistor R9, which set the trigger switching threshold, i.e. the power supply voltage. "Hysteresis" switching (the difference between the upper and lower switching thresholds) depends mainly on the resistor R7 and with the resistance indicated on the diagram it is about 1.5 V.

The trigger is connected to the conductors connected to the battery conclusions, and switches depending on the voltage on them.

The VT1 transistor is connected by the base chain to the trigger and works in the electronic key mode. The collector of the transistor circuit is connected via resistors R2, R3 and a portion control electrode - a thyristor cathode with a minus output of the charger. Thus, the basic and collector circuit of the transistor VT1 is powered by different sources: base - from the battery, and the collector-out of the charger.

Thyristor VS1 performs the role of a commuting element. Using it instead of contacts of an electromagnetic relay, which is sometimes used in these cases, provides a large number of inclusions - shutdown of the charging current required to recharge the battery during long-term storage.

As can be seen from the scheme, the vs1 thyristor is connected to the cathode to the minus wire of the charger, and the anode to the minus output of the battery. With this option, the control of the thyristor is simplified: with an increase in the instantaneous value of the pulsating voltage at the output of the charger via the control electrode of the thyristor immediately begins to flow (unless the VT1 transistor is open). And when a positive (relative to the cathode) voltage appears on the anode of the thyristor, the thyristor will be securely open. In addition, such inclusion is beneficial to the fact that a thyristor can be fixed directly to metal corps The console machine or the charger housing (in the case of placing the console inside it) as the heat sink.

The SA1 switch can be turned off the prefix by putting it to the "manual" position. Then the switch contacts will be closed, and through the R2 resistor, the thyristor control electrode will be connected directly to the charging device outputs. This mode is needed, for example, to quickly charge the battery before installing it on the car.

The control node setting is to check its performance and determining the position of the engine of the adjustable resistor R9. To do this, to the output terminals of the console, connect the rectifier direct current With adjustable output voltage up to 15 V. The engine of the trim resistor R9 is set to the lower position of the position and is fed to the voltage control unit of about 13 V. HL1 and HL2 LEDs should be buried. Moving the engine of the trim resistor R9 upwards is achieved by the ways to extract the HL1 LED. Smoothly increasing the supply voltage of the control unit up to 15 V and reducing up to 12 V, it is achieved by a detailed resistor so that the HL1 LED will be lit at a voltage of 12.8 ÷ 13 V and went out at 14.2 ÷ 14.V.

Details Charger console

The VT1 transistor can be specified on the SIM Scheme with lettering indexes A ÷ r; VT2 and VT3 - CT603A ÷ KT603G.

Diode VD1 - any of the series D219, D220 or other silicon.

Stabilitron VD2 - D814A, D814B, D808, D809.

LEDs - any of the series al102, al307 (restrictive resistors R1 and R11 set the desired direct current of the used LEDs).

Permanent resistors - MLT-2 (R2), MLT-1 (R6), MLT-0.5 (R1, R3, R8, R11), MLT-0.25 (other). Personnel resistor R9 - SP5-16B, but is suitable for another, resistance of 330 Ohm 1.5 com. If the resistance of the resistor is more specified in the diagram parallel to its terminals, the constant resistor of such resistance is connected so that the total resistance is 330 ohms.

Thyristor - CU202 series with letterpoint indices g, e, and, l, n, and also D238G, D238E.

To install a thyristor, you can make a heat sink with a total area of \u200b\u200babout 200 cm 2. Suitable, for example, a plate of duralumin with a thickness of 3 mm and sizes of 100x100 mm. The heat sink is attached to one of the walls of the housing (say, rear) at a distance of about 10 mm - to ensure air convection.

Chargers of car batteries are recommended to equip it with a machine that connects it when the voltage is reduced. On the battery to the minimum value and turning off at the end of the charge. In particular, it is necessary when applying as a spare power source or with long-term battery storage without exploitation - to prevent a self-discharge.

Description of the operation of the automaton for disconnecting the charger

The described electrical machine to disable the charger on the battery for charging while the voltage is reduced on it. Up to the specified level and turns off when the maximum is reached. Limit voltage for acid batteries The car serves a voltage of 14.2-14.5 volts, and the minimum allowed when discharge - 10.8 volts. The minimum is recommended to limit for consuming reliability with a voltage of 11.5 ... 12 volts.

The reduced electrical circuit contains a comparator on the transistors VT1, VT2 and the key on VT3, VT4. The electrical circuit is functioning as follows. Following the connection of AB and and supply the voltage of the power grid, you must press the SB1 "Start" button. Transistors VT1 and VT2 locked up, unscrewing the key VT3, VT4, which activates the electrorel K1.

The relay with its normally closed conclusions K1.2 turns off the K2 electrorele, normally closed conclusions of which (K2.1), connect the charger (memory) to the network. Such a complex electrical connection scheme is applied to 2nd reasons:

• first, the galvanic isolation of high-voltage electrocups from low-voltage is created;
• secondly, in order for the K2 electrorel activated at maximum voltage. battery and disconnected with minimal, because Used electric RES22 (passport of the Russian Federation 4500163) has work voltage equal to 12 ... 12,5 V.

Contacts K1.1 Electrorele K1 are transferred to the lower position according to the scheme. During the charge of the battery, the potential on the resistances R1 and R2 increases, and when the opening voltage is reached on the basis of the VT1, the VT1 and VT2 transistors are unscrewed, locked the key VT3, VT4.

The K1 relay turns off, including K2. Normally closed conclusions K2.1 are blocked and disconnected by the charger. Conclusions K1.1 are switched to the top according to the position scheme. Now the potential on the basis of the composite transistor VT1, VT2 is determined by a drop in voltage. on the resistances R1 and R2. During the discharge, AB potential on the VT1 database decreases, and at a certain point, VT1, VT2 is closed, opening the key VT3, VT4. The charge cycle is again carried out. Capacity C1 is designed to eliminate interference from the rattles of contacts K1.1 during switching time.

Setting the machine to disable charger

The instrument setting is made without a battery and charger. You need an adjustable power supply with an adjustment limits of 10 ... 20 V. It is connected to contacts electrical circuit Instead of GB1. The R1 resistance engine is transferred to the upper position, and the R5 engine is at the bottom. Source voltage makes equal to min battery voltage (11.5 ... 12 V).

Moving the R5 engine is to turn on the electrorel K1 and the VD7 LED. Then, by increasing the power supply voltage to 14.2 ... 14.5 volts, the movement of the R1 potentiometer is shutdown to K1 and the LED. Changing the power supply voltage in both directions, make sure that the connection of the machine is performed at a voltage. 11.5 ... 12 V, and shutdown - at 14.2 ... 14.5 V. On this setting ends. The role of R1 and R5 is recommended to use multi-turn variables of the SP5-3 brand resistors or similar.

K. Selyugin, Novorossiysk