DIY generator voltage regulator relay diagram

I thought about this thing last winter, when short trips around the city (home-work, home-shop, etc.) with all consumers turned on began to make themselves felt. Many people have probably heard about installing a “boost diode on the voltage regulator,” and so, after reading this article, I thought: in this situation, the voltage in the on-board network is not manually regulated, it simply becomes greater by the value by which the voltage drops when current passes through a diode. First, a little theory: when current passes through a diode, the voltage drops by an average of 0.5 volts (depending on the diode), and the standard regulator thinks that the voltage has dropped in the on-board network and makes the generator produce more voltage. Practice: we take the same circuit as for the “boost diode” and add to it a second diode and a 3-position switch, and you can use any diode, just so that it is designed for a current of at least 5A, then we assemble everything like this scheme

And voila first position 14.2 V, second position 15.4 V, third position 14.8 V

The voltage stabilizer in the on-board electrical system of a car is the most important component without any exaggeration. Not only the stability and longevity of the battery will depend on the quality of its work. At the same time, even a completely serviceable stabilization device does not always guarantee compliance with the voltage and quality of power supply of the vehicle’s electrical network. Car enthusiasts often wonder how to make the generator voltage regulator relay more reliable - contact a service station specialist, assemble or improve it yourself? There are many options.

Modern stabilizers

On modern vehicles, as a rule, self-oscillating relays are installed. They work on the principle of turning off the power to the excitation coil when the voltage reaches the upper limit of 13.5-13.8 V and connecting at the lower voltage threshold of 14.5-14.6 V.

Thus, the output voltage fluctuates constantly. Theoretically, this is not considered a disadvantage, since the voltage does not exceed acceptable limits. Still, this is not entirely safe. Surely experienced drivers know that the weak point of this type of relay is the transition moments when the rotor speed or load current changes sharply. A particularly unfavorable moment occurs with a large load current at low speeds. At these moments, voltage fluctuations often exceed the upper threshold. Due to the short duration of such surges, the battery will not fail immediately, but each time its capacity and, accordingly, resource is reduced.

This problem is solved in different ways. Sometimes car enthusiasts simply replace the self-oscillating relay with an outdated contact-vibration relay. A more optimal solution would be to replace the relay with a pulse-width stabilizer or upgrade the “native” one with the help of small additions.

SHI stabilizer

Pulse-width stabilizers are characterized by more stable operation, that is, an almost constant voltage is supplied to the vehicle network, and small deviations within the normal range are smooth. The device circuit uses the same parts as in the original, but at the same time the K561TL1 microcircuit is included. This made it possible to assemble a multivibrator and a short pulse shaper on the 1st node. The output switch control unit has also been simplified due to the use of a field-effect transistor with increased power.

Stabilizer operation cycle

When the ignition is turned on, a low logic level appears at the output of trigger DD1.1. As a result, transistor VT1 opens with the charging current of the capacitor SZ. It, in turn, begins to supply a high level to the inputs of element DD1.2, simultaneously discharging capacitor C4. When a low level appears at the output, DD1.2 opens the field-effect transistor VT3. The current from the stabilizer output flows through the excitation winding of the generator.

After the pulse stops, a high level is formed at the output of DD1.1 and transistor VT1 closes. Capacitor C4 is charged by the current passing through resistor R5 from the generator, which is controlled by transistor VT2. While the voltage on capacitor C4 drops to the lower switching limit of trigger DD1.2, it will switch. A high level will appear at its output, which will close transistor VT3. In order to protect the input circuits of the DD1 microcircuit, the voltage of capacitor C4 is limited by the diode VD4, which, when it is subsequently charged, will not lead to switching DD1.2. When a low-level pulse is again formed at the output of the generator, the process begins to repeat.

Thus, stabilization is carried out by the duration of the on state of the field-effect transistor, and the process is controlled by a measuring device, as well as a current generator. When the voltage at the generator output increases, the collector current of transistor VT2 increases. As the amperage increases, capacitor C4 begins to charge faster and the duration of the on state of transistor VT3 decreases. As a result, the current that flows through the excitation winding of the generator decreases and, of course, the output voltage of the generator decreases.

When the voltage at the output from the generator decreases, the current at the collector of transistor VT2 decreases. As a result, the charging time of capacitor C4 increases. This leads to a longer period of switching on of the transistor VT3 and the current that flows through the excitation winding of the generator increases. The generator output voltage also increases.

Scheme number 2

The new circuit also has a three-pin electrical connection. component (but this is no longer a transistor) constant and variable resistors, an LED with its own limiter. Only two electrolytic capacitors have been added. Typically, typical diagrams indicate the minimum values of C1 and C2 (C1=0.1 µF and C2=1 µF) which are necessary for stable operation of the stabilizer. In practice, capacitance values range from tens to hundreds of microfarads. The containers should be located as close to the chip as possible. For large capacities, the condition C1>>C2 is required. If the capacitance of the capacitor at the output exceeds the capacitance of the capacitor at the input, then a situation arises in which the output voltage exceeds the input, which leads to damage to the stabilizer microcircuit. To exclude it, install a protective diode VD1.

This scheme has completely different possibilities. Input voltage is from 5 to 40 volts, output voltage is 1.2 - 37 volts. Yes, there is an input-output voltage drop of approximately 3.5 volts, but there are no roses without thorns. But the KR142EN12A microcircuit, called a linear adjustable voltage stabilizer, has good protection against excess load current and short-term protection against short circuits at the output. Its operating temperature is up to + 70 degrees Celsius, works with an external voltage divider. Output load current is up to 1 A during long-term operation and 1.5 A during short-term operation. The maximum permissible power when operating without a heat sink is 1 W, if the microcircuit is installed on a radiator of sufficient size (100 cm2) then P max. = 10 W.

Voltage Regulator Upgrade

This is another option to improve the quality of the relay and its resistance to transient moments. The standard relay 50.3702-01 was taken as a basis, with only one resistor and capacitor added to the circuit.

In the diagram, the modification is indicated in red and, as you can see, does not require much effort or special experience in radio electronics. When the voltage in the on-board electrical network increases, capacitor C2 begins to charge. In this case, part of the current flows through the base of transistor VT1 and is proportional in magnitude to the rate of voltage increase. This leads to the opening of transistor VT1 and the closing of transistors VT2 and VT3. In this case, the current in the excitation coil decreases, and earlier than without an additional installed circuit. This allows you to significantly reduce voltage fluctuations in the network or eliminate them altogether. The same goes for reducing voltage. In other words, the permissible voltage limits are narrowed, and the smoothness of stabilization increases.

In this diagram, you can also introduce another rational proposal. As you know, the output voltage of the generator is optimized depending on the ambient temperature and in winter it should be higher by 0.8 V, reaching somewhere around 14.6 V. According to the standard, seasonal adjustment is performed by removing or installing jumpers S1, S2 and S3. Installing jumpers eliminates resistors R1, R2 and R3 from the circuit and the output voltage increases. When the jumpers are removed, the transistors turn on again and the voltage drops. To avoid this, the mentioned transistors can be replaced with one trimmer and the output voltage can be adjusted more easily and with greater accuracy.

A generator voltage regulator relay has been created to adjust the “voltage” supplied to the on-board network and to the battery terminals in a given range of 13.8 - 14.5 V (less often up to 14.8 V). In addition, the regulator adjusts the voltage on the self-excitation winding of the generator.

Recommendations for increasing the service life of the regulator

In order to increase the service life of the voltage regulator, it is necessary to adhere to several simple rules aimed at implementing preventive measures. Among them:

do not allow excessive contamination of the generator, periodically inspect its condition, and, if necessary, dismantle and clean the unit;
check the tension of the alternator belt, tighten it if necessary (either yourself or in a car service);
monitor the condition of the generator windings, in particular, do not allow them to darken;
check the contact on the control wire of the relay-regulator, both its quality and the presence of oxidation on it;
Perform periodic voltage checks on the vehicle battery with the engine running.

Following these simple rules will allow you to increase the resource and service life of both the generator and the vehicle voltage regulator.

Results

Checking the voltage regulator relay is not a difficult task, and almost any car enthusiast with basic repair skills can handle it. The main thing is to have the appropriate tools for this - a multimeter, a power supply with a voltage regulator (although you can connect it to a battery with a charger), a 12 V lamp and pieces of wires for mounting the appropriate circuit.

If during the inspection you find out that the regulator is out of order, then it must be replaced (repair work is usually not carried out). The main thing is not to make a mistake when choosing it and purchase the part that is suitable specifically for your car.

The electrical network of any car is powered by a generator, which is driven by the engine using a belt drive. Its revolutions are constantly changing, ranging from 900 to several thousand, causing the rotor to rotate accordingly. For the normal operation of all electrical appliances and charging the battery, the voltage in the on-board network must be stable, which is ensured by the relay regulator. Being the weakest link in the power supply system, the device first of all needs to be checked when problems with battery charging and other breakdowns in the vehicle's electrical network are detected.

Purpose of the voltage regulator relay

Regardless of experience and driving style, the car owner cannot ensure the same engine speed at different times. That is, the crankshaft of the internal combustion engine, which transmits torque to the generator, rotates at different speeds. Accordingly, the generator produces different voltages, which is extremely dangerous for the battery and other consumers of the on-board network.

Therefore, replacing the alternator regulator relay should be done when the battery is undercharged or overcharged, the light is on, the headlights are flashing and other interruptions in the power supply to the on-board network.

Interconnection of car current sources

The vehicle contains at least two sources of electricity:

battery - required at the moment of starting the internal combustion engine and the primary excitation of the generator winding; it does not create energy, but only consumes and accumulates at the time of recharging
generator – powers the on-board network at any speed and recharges the battery only at high speeds

Both of these sources must be connected to the on-board network for the correct operation of the engine and other electricity consumers. If the generator breaks down, the battery will last for a maximum of 2 hours, and without the battery, the engine driving the generator rotor will not start.

There are exceptions - for example, due to the residual magnetization of the excitation winding, the standard GAZ-21 generator starts on its own, subject to constant operation of the machine. You can start a car “from a pusher” if it has a DC generator installed; with an AC device, such a trick is impossible.

Voltage regulator tasks

From a school physics course, every car enthusiast should remember the principle of operation of a generator:

when the frame and the surrounding magnetic field move mutually, an electromotive force arises in it
The stators serve as the electromagnet of DC generators, the EMF, accordingly, arises in the armature, the current is removed from the collector rings
In the alternating current generator, the armature is magnetized, electricity appears in the stator windings

In a simplified way, we can imagine that the magnitude of the voltage output from the generator is influenced by the value of the magnetic force and the speed of rotation of the field. The main problem of DC generators - burning and sticking of brushes when removing large currents from the armature - has been solved by switching to alternating current generators. The excitation current supplied to the rotor to excite magnetic induction is an order of magnitude lower, making it much easier to remove electricity from a stationary stator.

However, instead of terminals “–” and “+” constantly located in space, car manufacturers received a constant change in plus and minus. Recharging the battery with alternating current is not possible in principle, so it is first rectified with a diode bridge.

From these nuances the tasks solved by the generator relay flow smoothly:

adjusting the current in the excitation winding
maintaining a range of 13.5 - 14.5 V in the on-board network and at the battery terminals
cutting off the power to the excitation winding from the battery when the engine is turned off

Therefore, the voltage regulator is also called a charging relay, and the panel displays a warning light for the battery charging process. The design of alternating current generators includes a reverse current cut-off function by default.

Symptoms of a problem

So, in case of low voltage, the battery simply will not charge. That is, in the morning you will not be able to start the car, the lights on the dashboard may not even light up, or troubles will arise while driving. For example, dim headlights at night, unstable operation of the electrical system (problems with electrical appliances - wipers, heaters, radio, etc.).

In case of increased voltage, there is a high probability of a decrease in the electrolyte level in the battery banks, or its boiling. A white coating may also appear on the battery case. When overcharging, the battery may behave inappropriately.

Signs, malfunctions and repair of the generator and voltage regulator

In addition, you can also identify the following signs of a faulty voltage regulator (in some cases, some of them may or may not be present, it all depends on the specific situation):

the control light on the dashboard (although this may be a sign of other malfunctions, for example, that it has burned out, the contact has fallen out, and so on);
after starting, the battery indicator on the dashboard does not go out, that is, there are obvious malfunctions in charging the battery;
the brightness of the headlights becomes dependent on the engine speed (you can check this somewhere in a deserted place by placing the car against a wall and accelerating - if the glow changes, then most likely the voltage regulator is faulty);
the car stopped starting normally the first time;
The battery is constantly ;
when the engine speed exceeds 2000 rpm, the indicators on the dashboard turn off ;
the dynamic characteristics of the car decrease , this is especially noticeable at high engine speeds;
In some cases, the battery may boil .

Types of regulator relays

Before you independently repair the voltage regulation device, you must take into account that there are several types of regulators:

external – increase the maintainability of the generator
built-in – in the rectifier plate or brush assembly
regulating by minus - an additional wire appears
positive regulating – economical connection scheme
for alternating current generators - there is no function for limiting the voltage on the excitation winding, since it is built into the generator itself
for DC generators – an additional option for cutting off the battery when the internal combustion engine is not working
two-level - obsolete, rarely used, adjustment by springs and a small lever
three-level – supplemented with a special comparison device board and a matching indicator
multi-level - the circuit has 3 - 5 additional resistors and a tracking system
transistor - not used in modern cars
relay – improved feedback
relay-transistor - universal circuit
microprocessor - small dimensions, smooth adjustment of the lower/upper threshold of operation
integral - built into brush holders, therefore they are replaced after the brushes wear out

Operating principle of the regulator relay

Thanks to built-in resistors and special circuits, the relay is able to compare the amount of voltage generated by the generator. After which, too high a value leads to the relay being turned off, so as not to overcharge the battery and damage electrical appliances connected to the on-board network.

Any malfunctions lead to precisely these consequences: the battery becomes faulty or the operating budget increases sharply.

Summer/winter switch

Regardless of the season and air temperature, the operation of the generator is always stable. As soon as its pulley begins to rotate, electric current is generated by default. However, in winter the insides of the battery freeze, and it replenishes the charge much worse than in summer.

The summer/winter switches are either on the body of the voltage regulator, or the corresponding connectors are marked with this designation, which you need to find and connect the wiring to them depending on the season.

There is nothing unusual in this switch, these are just rough settings of the regulator relay, which allows you to increase the voltage at the battery terminals to 15 V.

Connection to the generator's on-board network

If, when replacing a generator, you connect a new device yourself, you need to take into account the following nuances:

First you should check the integrity and reliability of the contact of the wire from the car body to the generator housing
then you can connect terminal B of the regulator relay with the “+” of the generator
Instead of “twists” that begin to heat up after 1–2 years of operation, it is better to use soldering of wires
the factory wire must be replaced with a cable with a minimum cross-section of 6 mm2 if, instead of a standard generator, an electrical appliance rated for a current of more than 60 A is installed
The ammeter in the generator/battery circuit shows which power source is currently higher in the on-board network

Regulator relay diagnostics

Voltage regulator failures can be determined by indirect signs. First of all, this is incorrect battery charging:

overcharge - the electrolyte boils away, the acid solution gets on the body parts
undercharging - the internal combustion engine does not start, the lamps are dimly lit

However, it is preferable to diagnose with instruments - a voltmeter or tester. Any deviation from the maximum voltage value of 14.5 V (in some cars the on-board network is designed for 14.8 V) at high speeds or the minimum value of 12.8 V at low speeds becomes the reason for replacing/repairing the regulator relay.

Built-in

Most often, the voltage regulator is integrated into the generator brushes, so a level inspection of this unit is necessary:

After removing the protective cover and loosening the screws, the brush assembly is removed out
When the brushes are worn out (less than 5 mm of their length remains), replacement must be carried out without fail.
Generator diagnostics with a multimeter are carried out complete with a battery or charger
The “negative” wire from the current source is closed to the corresponding regulator plate
The “positive” wire from the charger or battery is connected to a similar relay connector
the tester is set to voltmeter mode 0 - 20 V, the probes are placed on the brushes
in the range of 12.8 - 14.5 V there should be voltage between the brushes
when the voltage increases above 14.5 V, the voltmeter needle should be at zero

In this case, instead of a voltmeter, you can use a lamp, which should light in the specified voltage range and go out when this characteristic increases above this value.

The wire that controls the tachometer (marked W only on relays for diesel engines) is tested with a multimeter in tester mode. It should have a resistance of about 10 ohms. If this value decreases, the wire is “broken” and should be replaced with a new one.

Remote

There are no differences in diagnostics for the remote relay, but it does not need to be removed from the generator housing. You can check the generator voltage regulator relay with the engine running, changing the speed from low to medium, then high. Simultaneously with the increase in speed, you need to turn on the high beams (at a minimum), the air conditioner, the monitor and other consumers (at a maximum).

Thus, if necessary, the vehicle owner can replace the standard voltage regulator relay with a more modern modification of a built-in or remote type. Diagnostics of performance is available on your own with a regular car lamp.

Replacing the battery charging indicator relay

Work on replacing the VAZ 2106 charging lamp relay should be carried out in the following sequence:

We unscrew the 2 fasteners of the charging lamp relay and remove the product from the installed studs.
We mark the supply wiring with a marker or felt-tip pen to control the correctness of the reverse connection of the updated product. If the relay is incorrectly connected to the vehicle's power supply network, it stops functioning, which will create an emergency situation due to a sharp increase in the potential difference at the output contacts of the generator device.
We disconnect the wire circuit, replace the relay with a working product and carry out the reverse installation.

When testing the charging lamp relay, it is strictly forbidden to make a short circuit between the output elements of the circuit, because this will cause defects in the current rectifier unit. Before testing the charge regulator relay, you must ensure that the alternator belt tension is optimal. Other energy resources should not be connected to the electrical circuit of the generator excitation winding, because the voltage drop on the VAZ 2106 charging relay under study may exceed the optimal values.

On the “classic” you can find 2 types of voltage regulator relays: built into the generator and external. The difference lies in the model of the generator that is installed on the car.

On older Zhiguli models (VAZ 2101, 2102, 2103, 2106, 2121 with carburetor engines) a G-221 generator is installed, and the external voltage regulator is a small “box”, which is secured with two nuts on the left mudguard of the body. It is precisely the replacement of such a regulator that will be discussed in this article.

On later VAZ models (2104, 2105 and 2107) there is a G-222 generator, and the voltage regulator is already built into the generator housing and is a small black “tablet”.