Generator voltage regulator device. Generator operation and voltage regulator check. Generator Specifications

Introduction

The goal is to study the design and diagnostic parameters of voltage regulators.

1. Consider the designs of voltage regulators.

2. Study the procedure for connecting the generator and voltage regulator to the installation.

3. Remove diagnostic parameters of the voltage regulator according to the procedure for performing laboratory work.

4. Evaluate the results obtained.

5. Draw up a report on the work done.

Theory

The principle of operation of the voltage regulator

Voltage regulator maintains voltage on-board network within specified limits in all operating modes - when changing the generator rotor speed, electrical load, temperature environment. In addition, it can perform additional functions- protect the elements of the generating set from emergency conditions and overloads, automatically include the power circuit of the generating set or the excitation winding in the on-board network.

According to their design, regulators are divided into non-contact transistor, contact-transistor and vibration (relay regulators). A type of contactless transistor regulators are integrated regulators, made using a special hybrid technology, or monolithic ones - on a single crystal of silicon. Despite such diverse design, all regulators operate on the same principle.

The generator voltage depends on three factors - the rotation speed of its rotor, the load current and the magnitude of the magnetic flux created by the field winding, which depends on the current in this winding. Any voltage regulator contains:

· a sensitive element that senses the generator voltage (usually a voltage divider at the regulator input),

· comparison element, in which the generator voltage is compared with a reference value,

· a regulator that changes the current strength in the excitation winding if the generator voltage differs from the reference value.

In real controllers, the reference value may not necessarily be electrical voltage, but also any physical quantity, which maintains its value quite stably, for example, the spring tension force in vibration and contact-transistor regulators.

In transistor regulators, the reference value is the stabilization voltage of the zener diode, to which the generator voltage is supplied through a voltage divider. The current in the field winding is controlled by an electronic or electromagnetic relay.

The rotor speed and generator load change in accordance with the operating mode of the vehicle, and a voltage regulator of any type compensates for the effect of this change on the generator voltage by affecting the current in the field winding. In this case, a vibration or contact-transistor regulator connects and disconnects a resistor in series from the excitation winding circuit (in two-stage vibration regulators, when operating in the second stage, it “short-circuits” this winding to ground), and a non-contact transistor voltage regulator periodically connects and disconnects the excitation winding from power circuits.

In both options, the change in the excitation current is achieved by redistributing the time the controller switching element is in the on and off states.

If the strength of the excitation current must be increased, for example, to stabilize the voltage, then in vibration and contact-transistor regulators the turn-on time of the resistor is reduced compared to the time it is turned off, and in a transistor regulator the time when the excitation winding is turned on in the power circuit increases in relation to the time turning it off.

In Fig. Figure 2.1 shows the effect of the regulator on the current strength in the field winding for two generator rotor speeds n1 and n2, and the rotation speed n2 is greater than n1.

At a higher rotation speed, the relative time for switching on the excitation winding to the power circuit by the transistor voltage regulator decreases, the average value of the excitation current decreases, and thus voltage stabilization is achieved.

Rice. 2.1. Change in current in the field winding

at different rotor speed n(n2>n1)

ton and toff – the time the relay is in the on and off states, respectively.

As the load increases, the voltage decreases, the relative turn-on time of the winding increases, and the average current increases so that the generator set voltage remains virtually unchanged.

In Fig. Figure 2.2 presents typical control characteristics of a generator set, showing how the current in the field winding changes with a constant voltage and a change in rotation speed or load current. The lower limit of the controller switching frequency is 25-30 Hz.

Rice. 2.2. Dependence of generator voltage and current in the field winding on rotational speed (a) and load current (b)

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 normal operation all electrical appliances and battery charging, 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.

Principle of operation

The autogenerator voltage regulator is designed to maintain the voltage of the on-board network within the required limits under any operating mode and at different generator speeds, load changes and changes in external temperature. It is also capable of performing additional functions - protecting the generator from overloads and emergency mode operation, automatically connect to the on-board circuit of the excitation winding or the generator failure alarm system.

The operation of any voltage regulator is based on the same principle and is determined by the following factors:

1. Rotor speed.
2. The current strength that the generator delivers to the load.
3. An indicator of the magnetic flux created by the field winding current.

Higher rotor speeds determine an increase in generator voltage. An increase in current strength on the excitation winding makes the magnetic flux stronger, and at the same time the voltage. Any voltage regulator stabilizes it by changing the excitation current. When the voltage increases or decreases, the regulator decreases or increases the excitation current, regulating the voltage within the required limits.

The relay regulator itself is electronic circuit with exits to graphite brushes. It is installed both inside the generator body itself next to the brushes, and outside it, and then the brushes are attached to the brush holder.

Malfunctions

Most often, the relay regulator fails for the following reasons:

1. When the battery is working properly, there is no charging current, which is why it does not charge. This happens when the wires are poorly connected to the relay terminals or when the circuit from the generator to the battery is broken. Eliminated by fixing the wire in the circuit, checking and adjusting the voltage regulator and relay regulator.
2. Insufficient charging current with a discharged battery or high current with a fully charged battery is caused by a malfunction of the voltage regulator. It can be eliminated by adjusting the device or replacing it.
3. Burning and burnout of lamps with excessive heat occurs when the adjustment of the relay regulator is violated or the contacts are closed. Eliminated by disconnecting and cleaning the closed contacts, adjusting or replacing the voltage regulator.
4. High discharge current after stopping the motor. Occurs when the relay-regulator contacts close (contacts sintering, armature spring breaks) or the electrical wire short circuits. Repaired by finding and eliminating short circuit with the battery disconnected, checking and adjusting the current limiter, opening and cleaning the contacts, replacing the spring and adjusting its clearance and tension.

How to check the relay regulator

Failure of the relay regulator manifests itself in systematic undercharging or overcharging of the battery. The simplest check device is carried out by a tester in voltmeter mode on DC ranging from 0 to 20V. When the engine is not running, the probes of the device are connected to the battery terminals and record the voltmeter readings, which vary within 12-12.8 V depending on the battery condition.

Afterwards, start the engine and look at the instrument readings: the voltage should increase to 13-13.8 V, depending on the crankshaft speed. A further increase in speed should correspondingly increase the voltage. Yes, on medium frequency rotation it is 13.5-14 V, and at maximum it reaches 14-14.5 V. The absence of an increase in voltage after starting the engine indicates a malfunction of the relay regulator.

There is a possibility that the battery is not charging for another reason, for example, due to a malfunction in the generator itself. In order to establish a diagnosis, the relay-regulator is removed for a more accurate check using a tester and a 12-volt lamp. Additionally, you will need wires with terminals, a power supply or a charger in which the current can be adjusted.

After connecting the relay to the circuit and turning on the power supply, the lamp will light up. Use the voltage regulator to gradually increase the current and monitor the readings of the voltmeter or the scale of the connected tester. When readings are up to 14.5 V, the lamp should be on, and after exceeding it should go out. If, after decreasing below 14.5, it lights up again, then the relay-regulator is working. If the operation deviates in one direction or another, the relay will overcharge or not provide the necessary current for charging, which is a reason for replacing it.

Integrated relays, popularly called “chocolate bars,” used on older models of domestic cars are tested in a similar way. The circuit is also connected to the power supply or charger via a light bulb, which should go out when the required voltage limit is reached. In this case, you need to pay attention to the condition of the terminals, which, if dirty or oxidized, can create additional resistance and, if the relay is working, cause a loss of voltage.

Replacing the generator regulator relay

Relay replacement is necessary in the following cases:

1. Wear of the brushes, in which contact with the relay-regulator disappears and the generator does not work.
2. A breakdown in the device circuit, which causes an increase in voltage in the system.
3. Damage to the fasteners or housing, which can lead to a short circuit.

The process of replacing a device is considered using the Lada-Kalina generator as an example. Replacing the relay regulator is associated with dismantling the generator, and is carried out in the following order:

1. Removing the minus terminal from the generator.
2. Dismantling the generator.

3. Unsnap the plastic clips on the generator cover and remove it.

4. Disconnect the diode bridge connector.

5. Unscrewing the nut and dismantling the contact group bushing.

6. Unscrewing a pair of screws holding the relay regulator.

7. Dismantling the relay itself.

8. Assembly is carried out in reverse order.

The regulators maintain the generator voltage within certain limits for optimal operation of electrical appliances included in the vehicle's on-board network. All voltage regulators have measuring elements, which are voltage sensors, and actuators that regulate it.

Modern cars use semiconductor contactless electronic regulators, which, as a rule, are built into the generator and combined with the brush assembly. They change the excitation current by changing the time the rotor winding is switched on to the supply network. These regulators are not subject to misadjustment and do not require any maintenance other than monitoring the reliability of the contacts.

Voltage regulators have the property of thermal compensation - changing the voltage supplied to the battery, depending on the air temperature in the engine compartment for optimal battery charging. The lower the air temperature, the greater the voltage must be supplied to the battery and vice versa. The thermal compensation value reaches up to 0.01 V per 1°C.

Operating principle of the voltage regulator

The voltage of a generator without a regulator depends on the rotation speed of its rotor, the magnetic flux created by the field winding, and, consequently, on the current strength in this winding and the amount of current supplied by the generator to consumers. The higher the rotation speed and the excitation current, the greater the generator voltage; the greater the current of its load, the lower this voltage.

The function of the voltage regulator is to stabilize the voltage when the rotation speed and load changes by influencing the excitation current. Electronic regulators change the excitation current by turning on and off the excitation winding from the supply network, while changing the relative duration of the on-time of the excitation winding. If in order to stabilize the voltage it is necessary to reduce the excitation current, the switching time of the excitation winding is reduced; if it is necessary to increase it, it is increased.

The operating principle of the electronic regulator can be conveniently demonstrated using a fairly simple diagram of an EE 14V3 type regulator. from Bosch, presented in Fig. 5.6:

The voltage sensor is a zener diode VD2. When the specified voltage value is reached, the zener diode “breaks through” and current begins to flow through it. The voltage is supplied to the zener diode VD2 from the output of the generator "D+" through a voltage divider on resistors R1 (R3 and diode VD1, which performs temperature compensation. When the voltage is low, the zener diode does not pass electricity and through the bulbHL the current passes to the excitation winding of the generator. When the voltage reaches its maximum value, the zener diode breaks through and the electronic unit stops supplying current to the field winding (Fig. 5.7).

From Fig. 5.6 clearly shows the role of the HL lamp for monitoring the operating condition of the generator set (charge monitoring lamp on the car’s instrument panel). When the car engine is not running, closing the contacts of the ignition switch SA allows current from the battery GA to flow through this lamp into the excitation winding of the generator. This ensures the initial excitation of the generator. At the same time, the lamp lights up, signaling that there is no break in the excitation winding circuit. After starting the engine, almost the same voltage appears at the generator terminals “D+” and “B+” and the lamp goes out. If the generator does not develop voltage while the car engine is running, the HL lamp continues to light in this mode, which is a signal of a generator failure or a broken drive belt. The introduction of resistor R into the generator set helps to expand the diagnostic capabilities of the HL lamp. If this resistor is present, in the event of an open circuit in the field winding while the car engine is running, the HL lamp lights up.

Currently, more and more companies are switching to the production of generator sets without an additional excitation winding rectifier. In this case, the generator phase output is fed into the regulator. When the car engine is not running, there is no voltage at the generator phase output and the voltage regulator in this case goes into a mode that prevents the battery from discharging to the excitation winding. For example, when the ignition switch is turned on, the regulator circuit switches its output transistor into an oscillatory mode, in which the current in the field winding is small and amounts to fractions of an ampere. After starting the engine, the signal from the generator phase output switches the regulator circuit to normal mode work. In this case, the regulator circuit also controls the lamp for monitoring the operating condition of the generator set.

The generator voltage regulator relay is an integral part of the electrical system of any car. It is used to maintain voltage within a certain range of values. In this article you will learn about what designs of regulators exist on this moment, including mechanisms that have not been used for a long time will be considered.

Basic automatic control processes

It doesn't matter what type of generator set is used in the car. In any case, it has a regulator in its design. Automatic voltage regulation system allows you to maintain specific value parameter, regardless of the frequency with which the generator rotor rotates. The figure shows the generator voltage regulator relay, its diagram and appearance.

Analyzing physical basis, using which the generator set operates, we can come to the conclusion that the output voltage increases if the rotor speed becomes higher. It can also be concluded that voltage regulation is carried out by reducing the current supplied to the rotor winding as the rotation speed increases.

What is a generator

Any car generator consists of several parts:

1. A rotor with an excitation winding, around which an electromagnetic field is created during operation.

2. A stator with three windings connected in a star configuration (alternating voltage is removed from them in the range from 12 to 30 Volts).

3. In addition, the design contains a three-phase rectifier consisting of six semiconductor diodes. It is worth noting that the VAZ 2107 generator voltage relay-regulator in the injection system is the same.

But the generator will not be able to operate without a voltage regulation device. The reason for this is the voltage change over a very wide range. Therefore, it is necessary to use an automatic control system. It consists of a comparison device, control, executive, master and special sensor. The main element is the regulatory body. It can be either electrical or mechanical.

Generator operation

When the rotor begins to rotate, some voltage appears at the generator output. And it is supplied to the excitation winding through a control element. It is also worth noting that the generator set output is connected directly to the battery. Therefore, voltage is constantly present on the excitation winding. When the rotor speed increases, the voltage at the generator set output begins to change. A voltage regulator relay from a Valeo generator or any other manufacturer is connected to the generator output.

In this case, the sensor detects the change, sends a signal to a comparing device, which analyzes it, comparing it with given parameter. Further the signal is coming to the control device from which the supply is made to the Regulatory body is able to reduce the value of the current that flows to the rotor winding. As a result, the voltage at the generator set output is reduced. In a similar way, the mentioned parameter is increased in the event of a decrease in rotor speed.

Two-level regulators

A two-level automatic control system consists of a generator, a rectifier element, and a battery. It is based on an electric magnet, its winding is connected to the sensor. The driving devices in these types of mechanisms are very simple. These are ordinary springs. A small lever is used as a comparison device. It is mobile and makes switching. Executive device is contact Group. The regulatory body is constant resistance. Such a generator voltage regulator relay, the diagram of which is given in the article, is very often used in technology, although it is morally outdated.

Operation of a two-level regulator

When the generator operates, a voltage appears at the output, which is supplied to the winding of the electromagnetic relay. In this case, a magnetic field arises, with its help the lever arm is attracted. The latter is acted upon by a spring, which is used as a comparing device. If the voltage becomes higher than expected, the contacts of the electromagnetic relay open. In this case, a constant resistance is included in the circuit. Less current is supplied to the field winding. The voltage regulator relay for the VAZ 21099 generator and other domestic and imported cars operates on a similar principle. If the output voltage decreases, the contacts are closed, and the current strength changes upward.

Electronic regulator

For two-level mechanical regulators tension there is a big drawback - excessive wear of the elements. For this reason, instead of an electromagnetic relay, semiconductor elements operating in key mode began to be used. The operating principle is similar, only the mechanical elements are replaced by electronic ones. The sensitive element is made of fixed resistors. A zener diode is used as a driving device.

The modern relay-voltage regulator of the VAZ 21099 generator is a more advanced device, reliable and durable. The executive part of the control device operates on transistors. As the voltage at the generator output changes, the electronic switch closes or opens the circuit, and additional resistance is connected if necessary. It is worth noting that two-level regulators are imperfect devices. Instead, it is better to use more modern developments.

Three-level regulation system

The quality of regulation of such structures is much higher than that of those previously discussed. Mechanical structures were previously used, but are more common today contactless devices. All elements used in this system are the same as those discussed above. But the operating principle is slightly different. First, voltage is applied through a divider to a special circuit in which information is processed. It is possible to install such a generator voltage regulator relay (Ford Sierra can also be equipped with similar equipment) on any car if you know the device and connection diagram.

Here the actual value is compared with the minimum and maximum. If the voltage deviates from the value that is set, then specific signal. It is called a mismatch signal. It is used to regulate the current flowing to the excitation winding. The difference from a two-level system is that there are several additional resistances.

Modern voltage regulation systems

If the voltage regulator relay of the Chinese scooter generator is two-level, then expensive cars more advanced devices are used. Multilevel control systems can contain 3, 4, 5 or more additional resistances. There are also tracking automatic control systems. In some designs, you can refuse to use additional resistances.

Instead, the response frequency increases electronic key. It is simply impossible to use circuits with electromagnetic relays in servo control systems. One of the latest developments is a multi-level control system that uses frequency modulation. In such designs, additional resistances are required, which are used to control logic elements.

How to remove the relay regulator

Removing the generator voltage regulator relay (Lanos or domestic “Nine” is not important) is quite simple. It is worth noting that when replacing the voltage regulator, you only need one tool - a flat-head or Phillips screwdriver. There is no need to remove the generator or the belt and its drive. Most devices are located on back cover generator, and are combined into a single unit with a brush mechanism. Most frequent breakdowns occur in several cases.

Firstly, when completely erasing the graphite brushes. Secondly, in case of breakdown of a semiconductor element. How to check the regulator will be discussed below. When removing, you will need to disconnect the battery. Disconnect the wire that connects the voltage regulator to the generator output. By unscrewing both mounting bolts, you can pull out the device body. But the voltage regulator relay has an outdated design - it is mounted in the engine compartment, separately from the brush assembly.

Device check

The relay-regulator of the voltage of the VAZ 2106 generator, "kopecks", and foreign cars is checked equally. As soon as you remove, look at the brushes - they should be more than 5 millimeters long. If this parameter is different, the device must be replaced. To carry out diagnostics, you will need a constant voltage source. It would be desirable to be able to change the output characteristic. You can use a battery and a pair as a power source AA batteries. You also need a lamp, it must run on 12 Volts. You can use a voltmeter instead. Connect the plus from the power supply to the voltage regulator connector.

Accordingly, connect the negative contact to the common plate of the device. Connect a light bulb or voltmeter to the brushes. In this state, voltage should be present between the brushes if 12-13 Volts are supplied to the input. But if you supply more than 15 Volts to the input, there should be no voltage between the brushes. This is a sign that the device is working properly. And it doesn’t matter at all whether the voltage regulator relay of the VAZ 2107 generator or another car is diagnosed. If the control lamp lights up at any voltage value or does not light up at all, it means that there is a malfunction of the unit.

conclusions

In the electrical system of a car, the voltage regulator relay of the Bosch generator (as, indeed, of any other company) plays a very important role. Monitor its condition as often as possible and check for damage and defects. Cases of failure of such a device are not uncommon. At the same time, in best case scenario will run out accumulator battery. And in the worst case, the supply voltage in the on-board network may increase. This will lead to the failure of most electricity consumers. In addition, the generator itself may fail. And its repair will cost a tidy sum, and considering that the battery will fail very quickly, the costs will be astronomical. It is also worth noting that the Bosch generator voltage regulator relay is one of the leaders in sales. Him high reliability and durability, and the characteristics are as stable as possible.

Content:

Voltage is actually electricity. It exists as a primordial force, the influence of which on any objects entails consequences due to their properties. Therefore, the ability to control voltage and its magnitude means influencing the course of many processes in electrical circuits. And this is the most important thing in applied electrical engineering. Next, we'll talk about how to control electricity using a thyristor.

Such different voltages

Voltage can have different properties. Therefore, even the laws describing certain phenomena related to electricity are limited in application. For example, Ohm's law for a section of a circuit. And there are many such examples. Therefore, when specifying the properties of an electrical regulator, it is necessary to indicate exactly what voltage is meant. In general, two main types of it are considered - constant and alternating.

They are like the beginning and end of a certain interval, within which pulse signals are located in a huge variety. Both previously, now, and, most likely, in the future, only one element can regulate the value of all of them - a resistor. That is adjustable resistor– rheostat. It always provides the same effect, regardless of the type of voltage. And at any time. And the moment of time in relation to an alternating or pulsed signal is the basis for its definition.

What voltage does the thyristor regulate?

After all, depending on it, the voltage value changes. The resistor can be controlled by a signal at any time. But it is impossible to obtain such a result with a thyristor, because it is a switch. It has only two states:

• with minimal resistance when the key is closed;
• with maximum resistance when the key is open.

Therefore, a thyristor for an instantaneous voltage value cannot be considered as its regulator. Only within a sufficiently large time interval, during which many instantaneous signal values ​​are taken into account, can a thyristor be considered as a voltage regulator. Since such a quantity is referred to as effective value, it would be correct to clarify the definition of a regulator as

• thyristor voltage regulator.

How to connect the switch and load

The most attractive characteristic of thyristors from the very beginning of their appearance was their resistance to high current. As a result, these semiconductor devices have found wide application in a variety of powerful devices. However, in any case when an electrical regulator is considered, there is an electrical circuit with a load. In equivalent, the load is represented as a resistor with some impedance.

In order for the voltage across this resistor to change, it is necessary additional elements, which are connected to it either in series or in parallel. The first thyristors were non-locking. They could be opened (turned on) at any time. But to turn it off it was necessary to reduce the current to a certain minimum value. For this reason, non-lockable thyristors are used to this day only in electrical circuits of alternating or rectified current.

On constant voltage they were also used, but to a very limited extent. For example, in the first photoflashes with controlled light intensity. The light of a photoflash lamp, which by controlling a thyristor forms the necessary illumination of the object, gives visual representation about the thyristor as an electrical regulator for a lamp - load. The energy for this was provided by a capacitor, which was discharged through a special lamp. And in this case the flash of the greatest force was obtained.

But in order for the lamp to produce less light, a thyristor was turned on in parallel with it. The lamp turned on and illuminated the object. And a special optical sensor with a control circuit monitored its characteristics. And at the right moment he turned on the thyristor. He shunted the lamp, which turned off at the speed of the thyristor. In this case, part of the energy of the capacitor simply disappeared in the form of heat, without bringing any benefit. But at that time it could not have been otherwise - there were no lockable thyristors yet.

Types of thyristors and differences in circuits for their use

The thyristor was locked because charging current The capacitor was selected with this in mind. Of course, the scheme with serial connection thyristor and load are much more efficient. And it is widely used. All dimmers used to control lighting and electrical appliances operate according to this scheme. But there may be significant differences due to the type of thyristor used. The circuit with a symmetrical thyristor, which operates on alternating voltage when directly connected to the load, is simpler.

But if we compare symmetrical thyristors with conventional ones that pass current in one direction, we immediately notice the noticeably wider the lineup the latter. Moreover, the limit electrical parameters they have noticeably more. But it is necessary to have a rectifier. If a 220 V network is regulated, a rectifier bridge is required, which contains 4 powerful diodes. But every semiconductor device, regardless of whether it is a transistor, thyristor or diode, is characterized by a residual voltage.

It changes little according to the strength of the current flowing through it. And at the same time, on each of semiconductor devices heat dissipates. If the currents reach units of amperes, the thermal power will be units of watts. Cooling radiators will be required. And this is a deterioration in design indicators. That's why triac regulators more compact and economical. To give up rectifier bridge, use a circuit of two identical thyristors connected in parallel and counter.

Of course, this is a more economical solution in terms of losses. However, the keys must have appropriate limits reverse voltages. And this significantly limits the number of their models suitable for this scheme. In addition, it is more difficult to obtain symmetrical half-waves by controlling two switches than with one thyristor. But when great strength current, which in industrial installations can be hundreds of amperes or more when the thyristor is turned on, dissipates power of hundreds of watts. Dynamic losses heat up the keys even more.

For this reason, reducing the number of semiconductors in high-power electrical regulators is a critical challenge. The following images show industrial thyristor voltage regulators. IN modern assortment Among the mass-produced models of thyristors, there are lockable keys. They can be used in DC circuits.

Therefore, the problems of regulating voltages of thousands of volts with powers measured in megawatts are being successfully solved today various models thyristors.