Diagram of an automobile generator voltage regulator. The principle of operation and application of voltage regulators to improve the efficiency of electrical devices. Do-it-yourself diagnostics of the voltage regulator

Why does a generator need a regulator?

The generator set is designed to provide power to consumers included in the vehicle's electrical equipment system and to charge battery with the engine running. The output parameters of the generator must be such that in any modes of vehicle movement and engine operation there is no progressive discharge of the battery or its overcharging, and the consumers are supplied with voltage and current of the required value.
In addition, the voltage in on-board network vehicle powered by a generator set must be stable in wide range changes in rotation speed and loads.

Induction emf in accordance with Faraday's law depends on the speed of movement of the conductor in the magnetic field and the magnitude of the magnetic flux:

E = c×Ф×ω,

where c is a constant coefficient depending on the design of the generator;
ω - angular speed of the generator rotor (armature):
F - magnetic excitation flux.

Therefore, the voltage generated by the generator depends on the rotation speed of its rotor and the intensity of the magnetic flux created by the field winding. In turn, the power of the magnetic flux depends on the magnitude of the excitation current, which varies in proportion to the rotor speed, since the rotor is made in the form of a rotating electromagnet.
In addition, the current entering the field winding depends on the magnitude of the load supplied to the this moment consumers of the vehicle's on-board network. The higher the rotor speed and excitation current, the greater the voltage the generator generates, than more current load, the lower the generated voltage.

Voltage ripple at the output of the generator is unacceptable, since this can lead to failure of on-board consumers electrical network, as well as overcharging or undercharging of the battery. Therefore, the use of generator sets in cars as a source of electricity led to the use special devices, maintaining the generated voltage in a range acceptable for consumer operation. Such devices are called voltage regulator relays.
The function of the voltage regulator is to stabilize the voltage generated by the generator when the engine speed and load in the on-board electrical network change.

The easiest way to control the amount of voltage generated by the generator is by changing the amount of current in the excitation winding, thereby regulating the power of the magnetic field created by the winding. It would be possible to use a permanent magnet as a rotor, but control magnetic field It is difficult to create such a magnet, which is why generator sets of modern cars use rotors with electromagnets in the form of an excitation winding.

On cars, to regulate the generator voltage, discrete-type voltage regulators are used, the operation of which is based on the principle of operation of various types of relays. With the development of electrical engineering and electronics, generated voltage regulators have undergone significant evolution, from simple electromechanical relays called vibration voltage regulators to non-contact integral regulators, which have no moving mechanical elements at all.

Vibration voltage regulator

Let's consider the operation of the regulator using the example of a simple vibration (electromagnetic) voltage regulator.

Vibration voltage regulator ( rice. 1) has an additional resistor R o, which is connected in series to the field winding OB. The resistor value is designed to provide the required generator voltage at maximum frequency rotation. Regulator winding OR, wound on a core 4 , switched on to full generator voltage.

When the generator is not working, the spring 1 pulls the anchor 2 up while holding contacts 3 in a closed state. In this case, the excitation winding OB through the contacts 3 and anchor 2 connected to the generator, bypassing the resistor R o.

As the rotation speed increases, the excitation current of the operating generator and its voltage increase. This increases the current strength in the regulator winding and the magnetization of the core. While the generator voltage is less set value, forces of magnetic attraction of the armature 2 to the core 4 not enough to overcome the spring tension force 1 and contacts 3 The regulators remain closed, and the current passes into the excitation winding, bypassing the additional resistor.

When the generator voltage reaches the trip value U r the force of magnetic attraction of the armature to the core overcomes the tension force of the spring and the contacts of the voltage regulator open. In this case, an additional resistor will be connected to the excitation winding circuit, and the excitation current, which has reached the value I r, will begin to fall.
A decrease in the excitation current entails a decrease in the generator voltage, and this, in turn, leads to a decrease in the current in the winding OR. When the voltage decreases to the circuit value U z, the tension force of the spring will overcome the force of magnetic attraction of the armature to the core, the contacts will close again, and the excitation current will increase. With the engine and generator running, this process is repeated periodically with high frequency.
As a result, the generator voltage and excitation current pulsate. Average voltage U avg determines the generator voltage. Obviously, this voltage depends on the tension of the relay spring, so by changing the spring tension you can adjust the generator voltage.

The design of vibration regulators ( rice. 1, a) includes a number of additional components and elements, the purpose of which is to increase the frequency of armature oscillation in order to reduce voltage ripple (accelerating windings or resistors), reduce the influence of temperature on the value adjustable voltage(additional resistors made of refractory metals, bimetallic plates, magnetic shunts), voltage stabilization (equalizing windings).

The disadvantage of vibrating voltage regulators is the presence of moving elements, vibrating contacts that are subject to wear, and a spring whose characteristics change during operation.
These shortcomings were especially pronounced in generators. alternating current, in which the excitation current is almost twice as large as in generators direct current. The use of separate branches of the excitation winding power supply and two-stage voltage regulators with two pairs of contacts did not completely solve the problem and led to the complexity of the regulator design, so further improvement proceeded primarily along the path widespread use semiconductor devices.
First, contact-transistor designs appeared, and then contactless ones.

Contact transistor voltage regulators are a transitional design from mechanical regulators to semiconductor. In this case, the transistor performed the function of an element that interrupts the current into the excitation winding, and an electromechanical relay with contacts controlled the operation of the transistor. Such voltage regulators retained electromagnetic relays with movable contacts, however, thanks to the use of a transistor, the current flowing through these contacts was significantly reduced, thereby increasing the service life of the contacts and the reliability of the regulator.

In semiconductor regulators, the excitation current is regulated using a transistor, the emitter-collector circuit of which is connected in series to the excitation winding.
The transistor operates similarly to the contacts of a vibration controller. When the generator voltage increases above a given level, the transistor closes the excitation winding circuit, and when the regulated voltage level decreases, the transistor switches to the open state.

Electronic regulators change the excitation current by turning on and off the excitation winding from the supply network (additional diodes).
As the rotor speed increases, the generator voltage increases. When it starts to exceed the level 13.5…14.2 V, the output transistor in the voltage regulator is turned off and the current through the field winding is interrupted.
The generator voltage drops, the transistor in the regulator unlocks and again passes current through the field winding.

The higher the rotation speed of the generator rotor, the longer the time the transistor is in the locked state in the regulator, therefore, the more the generator voltage decreases.
This process of locking and unlocking the regulator occurs with high frequency. Therefore, voltage fluctuations at the generator output are insignificant, and it can practically be considered constant, maintained at the level 13.5…14.2 V.

Structurally, voltage regulators can be made in the form of a separate device, installed separately from the generator, or integral (integrated), installed in the generator housing. Integrated voltage regulators are usually combined with the generator brush assembly.

Below are circuit diagrams connection and operation of semiconductor voltage regulators various types and designs.

Voltage regulation not only improves power quality, but also improves performance production processes at industrial enterprises: to reduce product defects, improve their quality, increase the productivity of people and the productivity of mechanisms, and also, in some cases, reduce energy losses. Exist various ways voltage regulation. The variety of solutions is determined by the requirements for stability, required control accuracy, load parameters, economic and other factors.

Regulation in secondary power supplies

The magnitude of the rectified voltage in some cases needs to be changed. Such a need may arise when turning on powerful engines, glow generator lamps, to reduce current surges when turned on.

Regulation of the rectified voltage can be carried out on the AC side (input), on the DC side (output) and in the rectifier itself using adjustable valves.

The following are used as voltage regulators on the AC side:

Adjustable transformers or autotransformers.

Regulating chokes (magnetic amplifiers).

In an adjustable transformer or autotransformer, the primary or secondary winding performed with multiple outputs.

Using a switch, the number of turns of the winding changes and, therefore, output voltage transformer or autotransformer.

When switching the windings, some of the turns may be short-circuited by the switch motor, which will lead to the creation of excessively high currents in the closed turns and lead to failure of the transformer. Therefore, it is recommended to carry out such switching after disconnecting the transformer from the network. This is a big disadvantage.

Types of voltage regulators

1. By the number of nodes in one housing:

· voltage regulator only

· voltage regulator with rectifier electric current

· combined regulator for AC voltage and DC voltage with rectifier

2. According to the rated voltage in the network vehicle and voltage change:

· nominal voltage 6 or 12 V

AC voltage or DC voltage

3. According to the electrical power (load) of the regulator

4. According to the number of phases into 1-phase and 3-phase

5. According to the type of adjustable DC generator - for generators with independent excitation and permanent magnet generators.

Thyristor-based AC voltage regulators

Thyristor regulators can significantly reduce physical dimensions devices, reduce its cost and reduce energy losses, but they have significant disadvantages that limit their capabilities. Firstly, they introduce quite noticeable interference into the electrical network, which often negatively affects the operation of televisions, radios, and tape recorders. Thyristor regulators AC voltage widely used in electric drives, also for powering electrothermal installations. The use of thyristors for switching stator circuits asynchronous motors With squirrel-cage rotor allows us to solve the problem of creating a simple and reliable contactless asynchronous electric drive. You can effectively influence the processes of acceleration, deceleration, intensive braking and precise stopping. Spark-free switching, the absence of moving parts, and a high degree of reliability allow the use of thyristor regulators in explosive and aggressive environments.

Currently, the tasks of voltage regulation have received a material basis in the form of regulating and compensating devices. Constant voltage at each point of the network can be ensured by using local regulators in electrical circuits. Thus, the question arises about creating local systems for automatic voltage regulation in the electrical network.

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INTRODUCTION 3

Description of the device 4

Main purpose and scope 5

Types of voltage regulators 6

AC voltage regulators based on thyristors 7

AC voltage regulators based on magnetic amplifiers 8

transistor-based AC voltage regulators 9

synchronous compensator: purpose, operating principle 10

Working principle of voltage regulator 1 3

Conclusion 1 4

References 1 5

Introduction: Voltage regulation allows not only to improve the quality of electricity, but also to improve the progress of production processes at industrial enterprises: to reduce defective products, improve their quality, increase the productivity of people and the productivity of mechanisms, and in some cases reduce energy losses. Currently, the tasks of voltage regulation have received a material basis in the form of regulating and compensating devices. Calculations show that, as a rule, additional costs associated with the use of control devices and their automation are paid off by the savings that are achieved by improving voltage conditions in electrical networks and systems. Constant voltage at each point of the network can be ensured by using local regulators in electrical circuits. Thus, the question arises about creating local systems for automatic voltage regulation in the electrical network. It seems appropriate to build local system automatic control using transistors.

Purpose of the study: To study the principle of operation and application of voltage regulators to improve the efficiency of electrical devices.

Research objectives:

Find out the purpose and application of the voltage regulator.
Determine the types of voltage regulators.
Study the principle of operation of voltage regulators.
Draw conclusions about the work done.

1. Description of the device:

The voltage regulator is electrical appliance, which regulates electrical voltage, generated by an alternating current generator or a direct current generator in the range from 14 to 14.4 V at a nominal network voltage of 12 V and from 7 to 7.2 V at a nominal network voltage of 6 V.

The voltage, regulated within the specified range, ensures proper operation of the battery and protects devices from destruction. Prerequisite proper operation is to prevent the possibility of overloading the electrical power of the regulator. For example: The regulator has a maximum electrical power 200 W. This means that the power of the alternator must be P alt<= 200 Вт. Далее, суммарное электропотребление приборов в сети транспортного средства не должно превышать 200 Вт. If overloaded, the regulator may be destroyed, or the battery may be discharged and destroyed.

The AC voltage regulator provides an average voltage value within a specified range. This means that, for example, the voltage measured by an oscilloscope changes periodically by a greater amount than the nominal voltage. For example, +- 20 to 30 V. This average value ensures that devices such as light bulbs do not break. However, there is a rule according to which the sum of the electrical consumption of devices should be Ps[W]<= Preg[Вт]. То есть, регулятор необходимо выбирать согласно номинальному напряжению [В] и макс. электропотреблению [Вт].

2. Main purpose and scope:

Voltage regulation allows not only to improve the quality of electricity, but also to improve the progress of production processes at industrial enterprises: to reduce defective products, improve their quality, increase the productivity of people and the productivity of mechanisms, and in some cases reduce energy losses. There are various ways to regulate voltage. The variety of solutions is determined by the requirements for stability, required control accuracy, load parameters, economic and other factors.

Regulation in secondary power supplies

The magnitude of the rectified voltage in some cases needs to be changed. Such a need may arise when turning on powerful engines, heating generator lamps, to reduce current surges when turned on. Regulation of the rectified voltage can be carried out on the AC side (input), on the DC side (output) and in the rectifier itself using adjustable valves.

The following are used as voltage regulators on the AC side:

adjustable transformers or autotransformers.

regulating chokes (magnetic amplifiers).

In an adjustable transformer or autotransformer, the primary or secondary winding is made with several terminals. Using a switch, the number of turns of the winding and, consequently, the output voltage of the transformer or autotransformer changes. When switching the windings, some of the turns may be short-circuited by the switch motor, which will lead to the creation of excessively high currents in the closed turns and lead to failure of the transformer. Therefore, it is recommended to carry out such switching after disconnecting the transformer from the network. This is a big disadvantage.

3. Types of voltage regulators.

1. By the number of nodes in one housing:

voltage regulator only
voltage regulator together with electric current rectifier
combined regulator for AC voltage and DC voltage with rectifier

2. According to the rated voltage in the vehicle network and voltage change:

nominal voltage 6 or 12 V
AC voltage or DC voltage

3. According to the electrical power (load) of the regulator

4. According to the number of phases into 1-phase and 3-phase

5. As a type of adjustable DC generator for generators with independent excitation and generators with permanent magnets.

3.1. Thyristor-based AC voltage regulators:

Thyristor regulators can significantly reduce the physical size of the device, reduce its cost and reduce energy losses, but they have significant drawbacks that limit their capabilities. Firstly, they introduce quite noticeable interference into the electrical network, which often negatively affects the operation of televisions, radios, and tape recorders. Thyristor alternating voltage regulators are widely used in electric drives and also for powering electrothermal installations. The use of thyristors for switching stator circuits of asynchronous motors with a squirrel-cage rotor makes it possible to solve the problem of creating a simple and reliable contactless asynchronous electric drive. You can effectively influence the processes of acceleration, deceleration, intensive braking and precise stopping. Spark-free switching, the absence of moving parts, and a high degree of reliability allow the use of thyristor regulators in explosive and aggressive environments.

A generalized diagram of a thyristor alternating voltage regulator is shown in Fig. 1:

3.2. AC voltage regulators based on magnetic amplifiers:

Let's consider AC voltage regulators based on magnetic amplifiers, thyristors and transistors. A magnetic amplifier (MA) is a static electromagnetic device that allows, using a low-power DC control signal, to control significant powers in a circuitalternating current. The regulating choke (or magnetic amplifier) is switched on at the input of the rectifier. If the AC windings of the magnetic amplifier are connected in series with the load and the current in the control winding is changed, then the inductive reactance of the inductor windings and the voltage drop across these windings will change. Therefore, it will change. When increasing, decreasing, decreasing, decreasing and growing.

Voltage regulators built on the basis of magnetic amplifiers have a number of advantages: practically unlimited service life, ease of operation, high temperature and time stability of characteristics, high efficiency. Despite a number of advantages, regulators built on the basis of magnetic amplifiers are rarely used in modern control systems, since a significant disadvantage of such devices is their large dimensions and weight caused by the design features of magnetic amplifiers.

3.3. Transistor-based AC voltage regulators:

The transistor voltage regulator does not interfere with the electrical network and can be used to control loads with both active and inductive reactance. The regulator can be used to adjust the brightness of a chandelier or table lamp, the heating temperature of a soldering iron or hotplate, the rotation speed of a fan or drill motor, and the voltage on the transformer winding.

A generalized diagram of transistor AC voltage regulators is shown in Figure 2:

3.4. Synchronous compensator purpose, operating principle:

Understanding of the importance of power quality (the ratio of its active and reactive components power factor) is constantly growing, and along with it, the use of power factor correction (PFC) will grow. Improving the quality of electricity by increasing its power factor reduces costs and ensures a quick return on invested capital. In power distribution in networks with low and medium voltage, KKM focuses on the ratio of active and reactive components of power (cosφ) and optimization of voltage stability, by generating reactive power in order to increase the quality and stability of voltage at the distribution level.

Synchronous compensator, a synchronous electric motor operating without active load, designed to improve the power factor and regulate voltage in power lines and electrical networks. Depending on changes in the size and nature of the load (inductive or capacitive) of the electrical network, the voltage at the consumer changes (at the receiving ends of the line power transmission). If the load on the electrical network is large and inductive in nature, a capacitor system operating in an overexcited mode is connected to the network, which is equivalent to connecting a capacitive load. When transmitting electricity over a long line with a low load, the operating mode of the network is significantly affected by the distributed capacitance in the line. In this case, to compensate for the capacitive current in the network, a capacitor system operating in an underexcited mode is connected to the line. The constant voltage in the line is maintained by regulating the excitation current from the regulator voltage. Start K.s. carried out in the same way as conventional synchronous motors; starting current strength K.s. is 30100% of its nominal value. K. s. manufactured with a power of up to 100 kVA or more; powerful K. s. are hydrogen or water cooled. Mainly used in electrical substations.

Any electrical equipment that uses magnetic fields (motors, chokes, transformers, induction heating equipment, arc welding generators) is subject to a certain delay in the change in current, which is called inductance. This delay in electrical equipment maintains the direction of current for a certain time, despite the fact that negative voltage tries to change it. As long as this phase shift persists, current and voltage have opposite signs. The negative power produced all this time is fed back into the network. When the current and voltage are equal in sign again, the same energy is needed to restore the magnetic fields of the induction equipment. This magnetic reversal energy is called reactive power. In networks with alternating current voltage (50/60 Hz), this process is repeated 50-60 times per second. The obvious way out of this situation is the accumulation of reversal magnetic energy in capacitors in order to free up the network (power line). This is why automatic reactive power compensation systems (detuned/standard) are installed on high-power loads, for example, in factories. Such systems consist of several capacitor units that can be connected and disconnected as needed, and are controlled by a PFC controller based on current transformer data.

Low power factor (cosφ) leads to: increased energy costs and consumption, reduced power transmitted through the network, power losses in the network, increased transformer losses, increased voltage drop in distributed power networks. An increase in power factor can be achieved by: reactive power compensation with capacitors, active compensation use of semiconductors, overexcitation of synchronous machines (motor / generator)

In the power supply system, network losses account for 812% of production volume. To reduce these losses it is necessary: P distribute electrical loads; rationally transmit and distribute electrical energy; ensure the required degree of reliability; ensure the required quality of electricity; provide electricity O magnetic compatibility of the receiver with the network; save energy. Activities that can ensure the above objectives are creating A development of high-speed means of reactive power compensation, improvement h quality; reduction of losses is achieved by compensating for reactive power, increasing the load on transformers, reducing losses in them, bringing transformers closer to the loads, using energy savings h of new equipment and optimization of its operating modes. The operating mode of the power system is characterized by three parameters: voltage, current and active power. Auxiliary parameter reactive power. Reactive power and energy degrade the performance of energy systems And checks fuel consumption; losses in supply networks and receivers increase; The voltage drop in the networks increases. Jet mo sch power is consumed by such elements of the supply network as electrical transformers To power stations; main step-down power plants, power lines this accounts for 42% of the reactive power of the generator, of which 22% is at the O higher transformers; 6.5% on district power lines With Topics; 12.5% for step-down transformers. The main consumers of reactive power are asynchronous electric O engines that consume 40% of all power together with household and personal needs. In other words, there are power receivers that require reactive power. The reactive power supplied by the generator alone is clearly not enough. Uvel And It is impractical to measure the reactive power supplied by the generator due to the above reasons, i.e. need to issue reactive mo sch power exactly where it is needed most.

4. Operating principle of the voltage regulator:

Currently, all generator sets are equipped with semiconductor electronic voltage regulators, usually built inside the generator. Their designs and design may be different, but the operating principle of all regulators is the same. When connecting the regulator to the power supply, it is not allowed to change the + and poles of the battery. The regulator may be destroyed.

The voltage of a generator without a regulator depends on the rotation speed of its rotor, the magnetic flux created by the excitation 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. Of course, you can change the current in the excitation circuit by introducing an additional resistor into this circuit, as was done in previous vibration voltage regulators, but this method is associated with a loss of power in this resistor and is not used in electronic regulators. 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 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 increases.

Conclusion:

Voltage regulation allows not only to improve the quality of electricity, but also to improve the progress of production processes at industrial enterprises: to reduce defective products, improve their quality, increase the productivity of people and the productivity of mechanisms, and in some cases reduce energy losses. Having drawn conclusions about the design and application of the AC voltage regulator, we can say with confidence that this device can sufficiently facilitate the work of both radio technicians and the average person in using it to improve the quality of consumed electricity.

Bibliography:

Butov A. “Protection device for low-power incandescent lamps,” Magazine “Radio” No. 2, 2004.
Chekarov A. “Noise-free voltage regulator” Radio magazine, No. 11, 1999.
Fundamentals of radio engineering [Text] / N. M. Izyumov, D. P. Linde. - 4th ed., revised. and additional - M.: Radio and Communications, 1983. - 376 p. : ill. - (Mass Radio Library; issue 1059). - B. c.
Radio engineering [Text]: to the study of the discipline / I. P. Zherebtsov. - 4th ed., revised. and additional - M.: [b. i.], 1958. - 495 p. - B. c.
Workshop on electrical and radio engineering [Text]: a manual for students. ped. Institute / Ed. N.N. Malova. - M.: Uchpedgiz, 1958. - 166 p. - B. c.
Electrical and radio engineering course [Text]: textbook: for teachers. Institute / N.N. Malov. - M.: Gosfizmat, 1959. - 424 p. - B. c.

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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 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.

It is convenient to demonstrate the operating principle of the electronic regulator using a fairly simple diagram of an EE 14V3 type regulator from Bosch, shown 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 electric current and through the bulb HL 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 excitation 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 operation. In this case, the regulator circuit also controls the lamp for monitoring the operating condition of the generator set.

Electromechanical, in which, using vibrating contacts, the current in the excitation winding of an alternating current generator changes. The operation of the vibrating contacts is ensured in such a way that as the voltage of the on-board network increases, the current in the excitation winding decreases. However, vibration voltage regulators maintain voltage with an accuracy of 5-10%, because of this the durability of the battery and vehicle lighting lamps is significantly reduced.
Electronic on-board voltage regulators type YA112, which are popularly called “chocolate”. The disadvantages of this regulator are known to everyone - low reliability due to the low switching current of 5A and the installation location directly on the generator, which leads to overheating of the regulator and its failure. The voltage maintenance accuracy remains, despite the electronic circuit, very low and amounts to 5% of the rated voltage.

That's why I decided to make a device that is free from the above disadvantages. The regulator is easy to set up, the voltage maintenance accuracy is 1% of the rated voltage. The scheme shown in Fig. 1 was tested on many vehicles, including trucks, for 2 years and showed very good results.

Fig.1.

Principle of operation

When the ignition switch is turned on, +12V voltage is supplied to the electronic regulator circuit. If the voltage supplied to the zener diode VD1 from the voltage divider R1R2 is not enough for its breakdown, then transistors VT1, VT2 are in the closed state, and VT3 is in the open state. The maximum current flows through the excitation winding, the output voltage of the generator begins to increase, and when it reaches 13.5 - 14.2 V, a breakdown of the zener diode occurs.

Thanks to this, transistors VT1, VT2 open, respectively, transistor VT3 closes, the field winding current decreases and the output voltage of the generator decreases. A decrease in the output voltage by approximately 0.05 - 0.12V is enough for the zener diode to go into a locked state, after which transistors VT1, VT2 close, and transistor VT3 opens and current begins to flow through the excitation winding again. This process is continuously repeated with a frequency of 200 - 300 Hz, which is determined by the inertia of the magnetic flux.

Design

When manufacturing an electronic regulator, special attention should be paid to heat removal from transistor VT3. This transistor, operating in switching mode, no less produces significant power, so it should be mounted on a radiator. The remaining parts can be placed on a printed circuit board attached to the heatsink.

This results in a very compact design. Resistor R6 must have a power of at least 2W. The VD2 diode must have a forward current of about 2A and a reverse voltage of at least 400V; KD202Zh is best suited, but other options are possible. It is advisable to use transistors that are indicated on the circuit diagram, especially VT3. Transistor VT2 can be replaced with KT814 with any letter indices. It is advisable to install the VD1 zener diode in the KS series with a stabilization voltage of 5.6-9V (type KS156A, KS358A, KS172A), this will increase the accuracy of maintaining the voltage.

Settings

A properly assembled voltage regulator does not require special settings and ensures stability of the on-board network voltage of approximately 0.1 - 0.12V when the engine speed changes from 800 to 5500 rpm. The easiest way to set up is on a stand consisting of an adjustable power supply 0 - 17V and an incandescent light bulb 12V 5-10W. The positive output of the power supply is connected to the “+” terminal of the regulator, the negative output of the power supply is connected to the “Common” terminal, and the incandescent light bulb is connected to the “Ш” terminal and the “Common” terminal of the regulator.

The setting comes down to selecting resistor R2, which is changed within 1-5 kOhm, and the response threshold is achieved at 14.2V. This is the supported voltage of the on-board network. It cannot be increased above 14.5V, since this will sharply reduce the battery life.