8 basic DIY regulator circuits. Top 6 brands of regulators from China. 2 schemes. 4 Most asked questions about voltage regulators.+ TEST for self-test

Voltage regulator is a specialized electrical device designed to smoothly change or adjust the voltage supplying an electrical device.

Voltage regulator

Important to remember! Devices of this type are designed to change and adjust the supply voltage, not the current. The current is regulated by the payload!

TEST:

4 questions on the topic of voltage regulators

1. Why do you need a regulator:

a) Change in voltage at the output of the device.

b) Breaking the chain electric current

1. What does the regulator power depend on:

a) From the input current source and from the actuator

b) From the size of the consumer

1. The main parts of the device, which you can assemble yourself:

a) Zener diode and diode

b) Triac and thyristor

1. What are 0-5 volt regulators for?

a) Supply the microcircuit with a stabilized voltage

b) Limit the current consumption of electric lamps

Answers.

2 The most common do-it-yourself LV 0-220 volt circuits

Scheme No. 1.

The simplest and most convenient voltage regulator to use is regulator on thyristors connected in opposite directions. This will create a sinusoidal output signal of the required magnitude.

Input voltage up to 220V is supplied to the load through a fuse, and through the second conductor, through the power button, a sinusoidal half-wave reaches the cathode and anode thyristors VS1 and VS2. And through the variable resistor R2 the output signal is adjusted. Two diodes VD1 and VD2 leave behind only a positive half-wave arriving at the control electrode of one of thyristors, which leads to its discovery.

Important! The higher the current signal on the thyristor switch, the stronger it will open, that is, the more current it can pass through itself.

An indicator light is provided to control the input power, and a voltmeter is provided to adjust the output power.

Scheme No. 2.

A distinctive feature of this circuit is the replacement of two thyristors with one triac. This simplifies the circuit, makes it more compact and easier to manufacture.

The circuit also contains a fuse and a power button, and an adjusting resistor R3, and it controls the triac base; this is one of the few semiconductor devices with the ability to work with alternating current. Current passing through resistor R3 acquires a certain value, it will control the degree of opening triac. After this, it is rectified on the diode bridge VD1 and, through a limiting resistor, reaches the key electrode of the triac VS2. The remaining elements of the circuit, such as capacitors C1, C2, C3 and C4, serve to dampen the ripples of the input signal and filter it from extraneous noise and unregulated frequencies.

How to avoid 3 common mistakes when working with a triac.

1. The letter after the triac code indicates its maximum operating voltage: A – 100V, B – 200V, C – 300V, D – 400V. Therefore, you should not take a device with the letters A and B to adjust 0-220 volts - such a triac will fail.
2. A triac, like any other semiconductor device, gets very hot during operation; you should consider installing a radiator or an active cooling system.
3. When using a triac in load circuits with high current consumption, it is necessary to clearly select the device for the stated purpose. For example, a chandelier with 5 bulbs of 100 watts each will consume a total current of 2 amperes. When choosing from the catalog, you need to look at the maximum operating current of the device. So triac MAC97A6 is designed for only 0.4 amperes and will not withstand such a load, while MAC228A8 is capable of passing up to 8 A and is suitable for this load.

3 Key points when making a powerful LV and current with your own hands

The device controls loads up to 3000 watts. It is built on the use of a powerful triac, and it is controlled by a gate or key dinistor.

Dinistor- this is the same as a triac, only without a control output. If triac opens and begins to pass current through itself when a control voltage appears at its base and remains open until it disappears, then dinistor will open if a potential difference above the opening barrier appears between its anode and cathode. It will remain unlocked until the current between the electrodes drops below the locking level.

As soon as a positive potential hits the control electrode, it will open and allow alternating current to pass through, and the stronger this signal is, the higher the voltage will be between its terminals, and therefore across the load. To regulate the degree of opening, an decoupling circuit is used, consisting of a dinistor VS1 and resistors R3 and R4. This circuit sets the current limit on the switch triac, and capacitors smooth out ripples on the input signal.

2 basic principles in the manufacture of 0-5 volt pH

1. To convert the high input potential into a low constant potential, special LM series microcircuits are used.
2. The microcircuits are powered only by direct current.

Let's consider these principles in more detail and analyze a typical regulator circuit.

LM series microcircuits are designed to reduce high DC voltage to low values. For this purpose, there are 3 terminals in the device body:

• The first pin is the input signal.
• The second pin is the output signal.
• The third output is the control electrode.

The principle of operation of the device is very simple - the input high voltage of a positive value is supplied to the input output and then converted inside the microcircuit. The degree of transformation will depend on the strength and magnitude of the signal on the control “leg”. In accordance with the master pulse, a positive voltage will be created at the output from 0 volts to the limit for this series.

The input voltage, no higher than 28 volts and must be rectified, is supplied to the circuit. You can take it from the secondary winding of the power transformer or from a high voltage regulator. After this, the positive potential is supplied to the pin of microcircuit 3. Capacitor C1 smoothes out the ripple of the input signal. Variable resistor R1 with a value of 5000 ohms sets the output signal. The higher the current it allows through itself, the higher the chip opens. The output voltage of 0-5 volts is removed from output 2 and goes to the load through smoothing capacitor C2. The higher the capacitance of the capacitor, the smoother the output.

Voltage regulator 0 - 220v

Top 4 stabilizing microcircuits 0-5 volts:

1. KR1157 – domestic microcircuit, with an input signal limit of up to 25 volts and a load current of no higher than 0.1 ampere.
2. 142EN5A– a microcircuit with a maximum output current of 3 amperes, no higher than 15 volts is supplied to the input.
3. TS7805CZ– a device with permissible currents up to 1.5 amperes and increased input voltage up to 40 volts.
4. L4960– a pulse microcircuit with a maximum load current of up to 2.5 A. The input voltage should not exceed 40 volts.

RN on 2 transistors

This type is used in circuits of particularly powerful regulators. In this case, the current to the load is also transmitted through a triac, but the key output is controlled through a cascade transistors. This is implemented like this: a variable resistor regulates the current that flows to the base of the first low-power transistor, which, through the collector-emitter junction, controls the base of the second high-power one transistor and he already opens and closes the triac. This implements the principle of very smooth control of huge load currents.

Answers to the 4 most frequently asked questions regarding regulators:

1. What is the permissible deviation of the output voltage? For factory instruments of large companies, the deviation will not exceed + -5%
2. What does the regulator power depend on? The output power directly depends on the power source and on the triac that switches the circuit.
3. What are 0-5 volt regulators for? These devices are most often used to power microcircuits and various circuit boards.
4. Why do you need a 0-220 volt household regulator? They are used for smooth switching on and off of household electrical appliances.

4 DIY LV circuits and connection diagram

Let's briefly consider each of the schemes, features, and advantages.

Scheme 1.

Very simple circuit for connecting and smoothly adjusting the soldering iron. Used to prevent the soldering iron tip from burning and overheating. The circuit uses a powerful triac, which is controlled by a thyristor-variable chain resistor.

Scheme 2.

The circuit is based on the use of a phase control microcircuit of the type 1182PM1. It controls the degree of opening triac, which controls the load. They are used to smoothly control the degree of luminosity of incandescent light bulbs.

Scheme 3.

The simplest scheme for regulating the heat of a soldering iron tip. Made according to a very compact design using easily accessible components. The load is controlled by one thyristor, the degree of activation of which is regulated by a variable resistor. There is also a diode to protect against reverse voltage. The thyristor,

Chinese LV 220 volt

Nowadays, goods from China have become quite a popular topic, and Chinese voltage regulators do not lag behind the general trend. Let's look at the most popular Chinese models and compare their main characteristics.

It is possible to choose any regulator specifically for your requirements and needs. On average, one watt of useful power costs less than 20 cents, and this is a very competitive price. But still, it is worth paying attention to the quality of parts and assembly; for goods from China it still remains very low.

Introduction.

Many years ago, I made a similar regulator when I had to earn extra money repairing radios at a customer’s home. The regulator turned out to be so convenient that over time I made another copy, since the first sample was constantly installed as an exhaust fan speed regulator. https://site/

By the way, this fan is from the Know How series, as it is equipped with an air shut-off valve my own design. The material may be useful for residents living on the top floors of high-rise buildings and who have a good sense of smell.

The power of the connected load depends on the thyristor used and its cooling conditions. If a large thyristor or triac of the KU208G type is used, then you can safely connect a load of 200... 300 Watts. When using a small thyristor, type B169D, the power will be limited to 100 Watts.

How it works?

This is how a thyristor works in a circuit alternating current. When the current flowing through the control electrode reaches a certain threshold value, the thyristor is unlocked and locked only when the voltage at its anode disappears.

A triac (symmetrical thyristor) works in approximately the same way, only when the polarity at the anode changes, the polarity of the control voltage also changes.

The picture shows what goes where and where it comes out.

In budget control circuits for KU208G triacs, when there is only one power source, it is better to control the “minus” relative to the cathode.

To check the functionality of the triac, you can assemble such a simple circuit. When the button contacts close, the lamp should go out. If it does not go out, then either the triac is broken or its threshold breakdown voltage is below the peak value of the network voltage. If the lamp does not light when the button is pressed, then the triac is broken. The resistance value R1 is selected so as not to exceed the maximum permissible value of the control electrode current.

When testing thyristors, a diode must be added to the circuit to prevent reverse voltage.

Circuit solutions.

A simple power regulator can be assembled using a triac or thyristor. I will tell you about those and other circuit solutions.

Power regulator on triac KU208G.

VS1 – KU208G

HL1 - MH3... MH13, etc.

This diagram shows, in my opinion, the simplest and most successful version of the regulator, the control element of which is the KU208G triac. This regulator controls the power from zero to maximum.

Purpose of elements.

HL1 – linearizes control and is an indicator.

C1 – generates a sawtooth pulse and protects the control circuit from interference.

R1 – power regulator.

R2 – limits the current through the anode - cathode of VS1 and R1.

R3 – limits the current through HL1 and the control electrode VS1.

Power regulator on a powerful thyristor KU202N.

VS1 – KU202N

A similar circuit can be assembled using the KU202N thyristor. Its difference from the triac circuit is that the regulator power adjustment range is 50... 100%.

The diagram shows that the limitation occurs only along one half-wave, while the other passes freely through the diode VD1 into the load.

Power regulator on a low-power thyristor.

This scheme, assembled on the cheapest low-power thyristor B169D, differs from the circuit given above only by the presence of resistor R5, which, together with resistor R4, act as a voltage divider and reduce the amplitude of the control signal. The need for this is caused by the high sensitivity of low-power thyristors. The regulator regulates power in the range of 50... 100%.

Power regulator on a thyristor with an adjustment range of 0... 100%.

VD1... VD4 – 1N4007

In order for the thyristor regulator to control power from zero to 100%, you need to add a diode bridge to the circuit.

Now the circuit works similarly to a triac regulator.

Construction and details.

The regulator is assembled in the power supply housing of the once popular “Electronics B3-36” calculator.

The triac and potentiometer are placed on a steel angle made of steel 0.5 mm thick. The corner is screwed to the body with two M2.5 screws using insulating washers.

Resistors R2, R3 and neon lamp HL1 are dressed in an insulating tube (cambric) and mounted using a hinged mounting method on other electrical elements of the structure.

To increase the reliability of fastening the plug pins, I had to solder several turns of thick copper wire onto them.

This is what the power regulators I've been using for years look like.

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And this is a 4-second video that allows you to make sure that it all works. The load is a 100 Watt incandescent lamp.

Additional material.

Pinout (pinout) of large domestic triacs and thyristors. Thanks to the powerful metal housing, these devices can additional radiator dissipate power 1... 2 Watts without significant changes in parameters.

Pinout of small popular thyristors that can control the network voltage at an average current of 0.5 Amperes.

Device type	Cathode	Manager	Anode
BT169D(E, G)	1	2	3
CR02AM-8	3	1	2
MCR100-6(8)	1	2	3

Thyristor power regulators are used both in everyday life (in analog soldering stations, electric heating devices, etc.) and in production (for example, to start powerful power plants). In household appliances, as a rule, single-phase regulators are installed; in industrial installations, three-phase ones are more often used.

These devices are electronic circuit, working on the principle of phase regulation, to control power in the load (more details about this method will be discussed below).

Operating principle of phase control

The principle of regulation of this type is that the pulse that opens the thyristor has a certain phase. That is, the further it is located from the end of the half-cycle, the greater the amplitude will be the voltage supplied to the load. In the figure below we see the reverse process, when the pulses arrive almost at the end of the half-cycle.

The graph shows the time when the thyristor is closed t1 (phase of the control signal), as you can see, it opens almost at the end of the half-cycle of the sinusoid, as a result, the voltage amplitude is minimal, and therefore, the power in the load connected to the device will be insignificant (close to the minimum). Consider the case presented in the following graph.

Here we see that the pulse that opens the thyristor occurs in the middle of the half-cycle, that is, the regulator will output half the maximum possible power. Operating at close to maximum power is shown in the following graph.

As can be seen from the graph, the pulse occurs at the beginning of the sinusoidal half-cycle. The time when the thyristor is in the closed state (t3) is insignificant, so in this case the power in the load approaches the maximum.

Note that three-phase power regulators work on the same principle, but they control the voltage amplitude not in one, but in three phases at once.

This control method is easy to implement and allows you to accurately change the voltage amplitude in the range from 2 to 98 percent of the nominal value. Thanks to this, smooth control of the power of electrical installations becomes possible. The main disadvantage of devices of this type is the creation high level interference in the electrical network.

An alternative to reduce noise is to switch the thyristors when the AC voltage sine wave passes through zero. The operation of such a power regulator can be clearly seen in the following graph.

Designations:

• A – graph of half-waves of alternating voltage;
• B – thyristor operation at 50% of maximum power;
• C – graph displaying the operation of the thyristor at 66%;
• D – 75% of maximum.

As can be seen from the graph, the thyristor “cuts off” half-waves, not parts of them, which minimizes the level of interference. The disadvantage of this implementation is the impossibility of smooth regulation, but for loads with high inertia (for example, various heating elements), this criterion is not the main one.

Video: Testing a thyristor power regulator

Simple power regulator circuit

You can adjust the power of the soldering iron using analog or digital soldering stations for this purpose. The latter are quite expensive, and it is not easy to assemble them without experience. While analog devices (which are essentially power regulators) are not difficult to make with your own hands.

Here is a simple diagram of a device using thyristors, thanks to which you can regulate the power of the soldering iron.

Radioelements indicated in the diagram:

• VD – KD209 (or similar in characteristics)
• VS-KU203V or its equivalent;
• R 1 – resistance with a nominal value of 15 kOhm;
• R 2 – variable resistor 30 kOhm;
• C – electrolytic type capacitance with a nominal value of 4.7 μF and a voltage of 50 V or more;
• R n – load (in our case it is a soldering iron).

This device regulates only the positive half-cycle, so the minimum power of the soldering iron will be half the rated one. The thyristor is controlled through a circuit that includes two resistances and a capacitance. The charging time of the capacitor (it is regulated by resistance R2) affects the duration of the “opening” of the thyristor. Below is the operating schedule of the device.

Explanation of the picture:

• graph A – shows a sinusoid of alternating voltage supplied to the load Rn (soldering iron) with a resistance R2 close to 0 kOhm;
• graph B – displays the amplitude of the sinusoid of the voltage supplied to the soldering iron with a resistance R2 equal to 15 kOhm;
• graph C, as can be seen from it, at the maximum resistance R2 (30 kOhm), the operating time of the thyristor (t 2) becomes minimal, that is, the soldering iron operates with approximately 50% of the nominal power.

The circuit diagram of the device is quite simple, so even those who are not very well versed in circuit design can assemble it themselves. It is necessary to warn that when this device operates, a voltage dangerous to human life is present in its circuit, therefore all its elements must be reliably insulated.

As already described above, devices operating on the principle of phase regulation are a source of strong interference in the electrical network. There are two options for getting out of this situation:

Regulator operating without interference

Below is a diagram of a power regulator that does not create interference, since it does not “cut off” half-waves, but “cuts off” a certain amount of them. We discussed the principle of operation of such a device in the section “The principle of operation of phase control,” namely, switching the thyristor through zero.

Just like in the previous scheme, power adjustment occurs in the range from 50 percent to a value close to the maximum.

List of radioelements used in the device, as well as options for replacing them:

Thyristor VS – KU103V;

Diodes:

VD 1 -VD 4 – KD209 (in principle, you can use any analogs that allow a reverse voltage of more than 300V and a current of more than 0.5A); VD 5 and VD 7 – KD521 (any pulse-type diode can be installed); VD 6 – KC191 (you can use an analogue with a stabilization voltage of 9V)

Capacitors:

C 1 – electrolytic type with a capacity of 100 μF, designed for a voltage of at least 16 V; C 2 – 33H; C 3 – 1 µF.

Resistors:

R 1 and R 5 – 120 kOhm; R 2 -R 4 – 12 kOhm; R 6 – 1 kOhm.

Chips:

DD1 - K176 LE5 (or LA7); DD2 –K176TM2. Alternatively, 561 series logic can be used;

R n – soldering iron connected as a load.

If no errors were made when assembling the thyristor power regulator, then the device starts working immediately after switching on; no configuration is required for it. Having the ability to measure the temperature of the soldering iron tip, you can make a gradation of the scale for resistor R5.

If the device does not work, we recommend checking the correct wiring of the radio elements (do not forget to disconnect it from the network before doing this).

I assembled this voltage regulator for use in various directions: regulating the engine speed, changing the heating temperature of the soldering iron, etc. Perhaps the title of the article does not seem entirely correct, and this diagram is sometimes found as, but here you need to understand that in essence the phase is being adjusted. That is, the time during which the network half-wave passes to the load. And on the one hand, the voltage is regulated (through the duty cycle of the pulse), and on the other, the power released to the load.

It should be noted that this device will cope most effectively with resistive loads - lamps, heaters, etc. Inductive current consumers can also be connected, but if its value is too small, the reliability of the adjustment will decrease.

The circuit of this homemade thyristor regulator does not contain any scarce parts. When using the rectifier diodes indicated in the diagram, the device can withstand a load of up to 5A (about 1 kW), taking into account the presence of radiators.

To increase the power of the connected device, you need to use other diodes or diode assemblies designed for the current you need.

The thyristor also needs to be replaced, because KU202 is designed for a maximum current of up to 10A. Among the more powerful ones, domestic thyristors of the T122, T132, T142 and other similar series are recommended.

There are not so many parts; in principle, mounted mounting is acceptable, but on a printed circuit board the design will look more beautiful and more convenient. Drawing of the board in LAY format. The D814G zener diode can be changed to any one with a voltage of 12-15V.

As a body, I used the first one that came across - one that was suitable in size. To connect the load, I brought out the connector for the plug. The regulator works reliably and actually changes the voltage from 0 to 220 V. Design author: SssaHeKkk.

Discuss the article THYRISTOR VOLTAGE REGULATOR

Thyristor voltage regulators are devices designed to regulate the speed and torque of electric motors. Regulation of rotation speed and torque is carried out by changing the voltage supplied to the motor stator, and is carried out by changing the opening angle of the thyristors. This method of controlling an electric motor is called phase control. This method is a type of parametric (amplitude) control.

They can be performed with both closed and open control systems. Open-loop regulators do not provide satisfactory speed control. Their main purpose is to regulate torque to obtain the desired operating mode of the drive in dynamic processes.

The power part of a single-phase thyristor voltage regulator includes two controlled thyristors, which ensure the flow of electric current at the load in two directions with a sinusoidal voltage at the input.

Thyristor regulators with closed control system are used, as a rule, with negative speed feedback, which makes it possible to have fairly rigid mechanical characteristics drive in the low speed zone.

Most effective use thyristor regulators for speed and torque control.

Power circuits of thyristor regulators

In Fig. 1, a-d shows possible circuits for connecting the rectifier elements of the regulator in one phase. The most common of them is the diagram in Fig. 1, a. It can be used with any stator winding connection scheme. The permissible current through the load (rms value) in this circuit in continuous current mode is equal to:

Where I t - permissible average value of current through the thyristor.

Maximum forward and reverse voltage of the thyristor

Where k zap - safety factor selected taking into account possible switching overvoltages in the circuit; - effective value of the line voltage of the network.

Rice. 1. Diagrams of power circuits of thyristor voltage regulators.

In the diagram in Fig. 1b there is only one thyristor connected to the diagonal of the bridge of uncontrolled diodes. The relationship between the load and thyristor currents for this circuit is:

Uncontrolled diodes are selected for a current half as much as for a thyristor. Maximum forward voltage on the thyristor

The reverse voltage across the thyristor is close to zero.

Scheme in Fig. 1, b has some differences from the diagram in Fig. 1, and on the construction of a control system. In the diagram in Fig. 1, and control pulses to each of the thyristors must follow the frequency of the supply network. In the diagram in Fig. 1b, the frequency of control pulses is twice as high.

Scheme in Fig. 1, c, consisting of two thyristors and two diodes, in terms of control capability, loading, current and maximum forward voltage of the thyristors is similar to the circuit in Fig. 1, a.

The reverse voltage in this circuit is close to zero due to the shunting effect of the diode.

Scheme in Fig. 1, g in terms of current and maximum forward and reverse voltage of the thyristors is similar to the circuit in Fig. 1, a. Scheme in Fig. 1, d differs from those considered in the requirements for the control system to ensure the required range of change in the control angle of the thyristors. If the angle is measured from zero phase voltage, then for the circuits in Fig. 1, a-c the relationship is correct

Where φ - load phase angle.

For the diagram in Fig. 1, d a similar relationship takes the form:

The need to increase the range of angle changes complicates things. Scheme in Fig. 1, d can be used when the stator windings are connected in a star without a neutral wire and in a triangle with the inclusion of rectifier elements in the linear wires. The scope of application of this scheme is limited to non-reversible, as well as reversible electric drives with contact reverse.

Scheme in Fig. 4-1, d is similar in its properties to the diagram in Fig. 1, a. The triac current here is equal to the load current, and the frequency of the control pulses is equal to double the frequency of the supply voltage. The disadvantage of a circuit based on triacs is that the permissible values ​​of du/dt and di/dt are significantly lower than those of conventional thyristors.

For thyristor regulators, the most rational diagram is in Fig. 1, but with two back-to-back thyristors.

The power circuits of the regulators are made with back-to-back thyristors connected in all three phases (symmetrical three-phase circuit), in two and one phase of the motor, as shown in Fig. 1, f, g and h, respectively.

In regulators used in crane electric drives, the most widespread is the symmetrical connection circuit shown in Fig. 1, e, which is characterized by the least losses from higher harmonic currents. Higher loss values ​​in circuits with four and two thyristors are determined by voltage asymmetry in the motor phases.

Basic technical data of thyristor regulators of the PCT series

Thyristor regulators of the PCT series are devices for changing (according to a given law) the voltage supplied to the stator of an asynchronous motor with a wound rotor. Thyristor regulators of the PCT series are made according to a symmetrical three-phase switching circuit (Fig. 1, e). The use of regulators of this series in crane electric drives allows for regulation of rotation speed in the range of 10:1 and regulation of engine torque in dynamic modes during start-up and braking.

Thyristor regulators of the PCT series are designed for continuous currents of 100, 160 and 320 A (maximum currents, respectively, 200, 320 and 640 A) and voltages of 220 and 380 V AC. The regulator consists of three power blocks assembled on a common frame (according to the number of phases of back-to-back thyristors), a block of current sensors and an automation block. The power blocks use tablet thyristors with coolers made of drawn aluminum profiles. Air cooling is natural. The automation unit is the same for all versions of regulators.

Thyristor regulators are made with a degree of protection IP00 and are intended for installation on standard frames of magnetic controllers of the TTZ type, which are similar in design to controllers of the TA and TCA series. Overall dimensions and weight of PCT series regulators are indicated in table. 1.

Table 1 Dimensions and weight of voltage regulators of the PCT series

The TTZ magnetic controllers are equipped with direction contactors for reversing the motor, rotor circuit contactors and other relay contact elements of the electric drive that communicate between the command controller and the thyristor regulator. The structure of the regulator control system can be seen from the functional diagram of the electric drive shown in Fig. 2.

The three-phase symmetrical thyristor block T is controlled by the SFU phase control system. With the help of the command controller KK in the regulator, the speed setting of the BZS is changed. Through the BZS block, as a function of time, the acceleration contactor KU2 in the rotor circuit is controlled. The difference between the task signals and the TG tachogenerator is amplified by amplifiers U1 and US. A logical relay device is connected to the output of the ultrasonic amplifier, which has two stable states: one corresponds to turning on the forward direction contactor KB, the second corresponds to turning on the reverse direction contactor KN.

Simultaneously with the change in the state of the logical device, the signal in the control circuit control circuit is reversed. The signal from the matching amplifier U2 is summed with the delayed feedback signal for the motor stator current, which comes from the TO current limiting unit and is fed to the input of the SFU.

The BL logic block is also influenced by a signal from the current sensor block DT and the current presence block NT, which prohibits switching of contactors in the direction under current. The BL block also carries out nonlinear correction of the rotation speed stabilization system to ensure the stability of the drive. Regulators can be used in electric drives of lifting and moving mechanisms.

Regulators of the PCT series are made with a current limiting system. The current limiting level for protecting thyristors from overloads and for limiting motor torque in dynamic modes smoothly changes from 0.65 to 1.5 of the rated current of the regulator, the current limiting level for overcurrent protection is from 0.9 to. 2.0 rated current of the regulator. A wide range of changes in protection settings ensures operation of a regulator of the same standard size with motors differing in power by approximately 2 times.

Rice. 2. Functional diagram of an electric drive with a thyristor regulator of the PCT type: KK - command controller; TG - tachogenerator; KN, KB - directional contactors; BZS - speed setting unit; BL - logic block; U1, U2. Ultrasound - amplifiers; SFU - phase control system; DT - current sensor; IT - current availability block; TO - current limiting unit; MT - protection unit; KU1, KU2 - acceleration contactors; CL - linear contactor: R - switch.

Rice. 3. Thyristor voltage regulator PCT

The sensitivity of the current presence system is 5-10 A of the effective value of the current in the phase. The regulator also provides protection: zero, against switching overvoltages, against loss of current in at least one of the phases (IT and MT units), against interference with radio reception. Fast-acting fuses of the PNB 5M type provide protection against short-circuit currents.