Tractor generator with self-excitation. Generators of tractors and cars MTZ what stands between the starter and the generator

The generator on tractors, as well as on other self-propelled machines, is designed to convert mechanical energy from the rotation of the engine crankshaft into electrical energy to power the tractor's on-board network and to charge the battery. Several types of generators were installed on MTZ tractors, depending on the configuration and year of manufacture, but they are all similar in design. These are three-phase AC electromechanical machines.

The electrical on-board network and the tractor battery operate on direct current, therefore, together with the generator, a rectifier is installed that converts alternating current into direct current, as well as a relay-regulator - a device that keeps the voltage generated by the generator within 14 - 15 volts at 12 volts. on-board network, or within 28 volts, if the on-board network is 24 volts, regardless of the speed of rotation and the number of simultaneously switched on devices.

The current arises in the generator due to the interaction of the electric magnetic fields of the rotating rotor and the stationary stator. The initial moment of occurrence of a magnetic field is called "excitation". The generators that were installed on MTZ tractors of different years of manufacture have a separate excitation winding, which is powered by the battery when the ground or ignition is turned on. However, older models of tractors did not have a starter and a battery in all trim levels. The diesel engine was started using a starting engine, which, in turn, was manually started by the machine operator. On such a tractor, the presence of a battery was optional. In such configurations, the excitation problem was solved by using permanent magnet generators instead of an excitation winding, which did not require current from the battery to generate an electromagnetic field. An example is G 46.3701, which was widely used at that time. Modern tractors are always equipped with starters and batteries, so the need to install self-excited models has disappeared.

The power of the generators installed on the MTZ tractors varies from 700 to 1500 watts, and is selected based on the working conditions and the equipment of the tractor with electrical appliances.

The history of the Minsk Tractor Plant begins in 1946. Early models of tractors did not have a rich equipment of electrical appliances, modern technology has many electrical systems and complex elements, such as on-board computers, air conditioning systems, multiple control systems, and the requirements for power and reliability of generators have increased accordingly.

For more than 30 years, the supplier of generators for MTZ tractors has been the Grodno plant "Radiovolna", which produces the entire model range installed on the equipment of the Minsk Tractor Plant.

Generators installed on internal combustion engines have in most cases a similar design. Each device includes the following elements:

• Stator. In fact, the stator is a housing. In addition to the bearing function, windings are located on the inner walls of the stator. The stator is assembled from thin steel plates. The stator winding is three-phase, each phase consists of three copper windings, which are connected in series. The phases themselves are connected according to the "triangle" scheme. The ends of the phases are connected to a rectifier, often referred to as a "diode bridge".
• Rotor. Rotating part. It is made in the form of a steel shaft, on which thin plates of electrical steel are assembled. In the generators of MTZ tractors, the shape of the plates forms a six-pointed star. The shaft is located inside the stator, mounted on bearings in the front and rear covers. A pulley for a drive belt is fixed on the front of the shaft. It is due to the rotation of the rotor that an electromagnetic field arises in the stator, which creates energy to power consumers and charge the battery.
• Rectifier. Designed to convert alternating current, which arises from the interaction of the electromagnetic fields of the stator and rotor, into direct current, which feeds all consumers of the on-board system, and which is necessary for the battery to charge. The rectifier is made in the form of a housing and a plate, depending on the model, one of these elements is a heat sink. Diodes are placed on these elements, which are connected in series with the stator windings and output voltage to the “+” or “B” terminal.
• Relay-regulator. Designed to maintain a constant voltage. In earlier electrical circuits of tractors, the relay-regulator was made as a separate unit connected to the terminals and to ground. In modern models, there is a transistor-type relay-regulator, combined with a brush assembly and installed directly on the generator. Some modifications of voltage regulators have the ability to seasonally adjust the voltage, changing the current range within 0.8-1.2 Volts.
• Front and back covers. They are the support of the rotor, which is mounted on bearings pressed into the castings of the covers. Also on the front or rear cover, depending on the model, a rectifier unit is installed. Mounting lugs are cast on the covers for attaching the generator to the engine and adjusting the tension of the drive belt. As a rule, covers have openings for heat removal from the generator.

Connection and principle of operation

Consider the connection using the example of the G-306 D generator, which was installed on the MTZ-82 tractor for a long period of time.

The positive wire from the battery is connected to the "B" or "+" terminal. In parallel with this terminal, there is a connection to the voltage regulator terminal of the same name. The generated voltage from the stator windings is output to the “+” or “B” terminal inside the generator through a diode rectifier. In parallel with this terminal, through a relay, a battery charge indicator lamp is connected.

If the generator is working properly, the control lamp lights up when the ignition is turned on and goes out when the engine is running. Additionally, in some models of MTZ tractors, an ammeter is installed, which shows the current strength in Amperes, or a voltmeter, which shows the voltage in Volts. These devices allow the machine operator to quickly receive information about the operation of the generator and the state of the on-board network during the operation of the tractor.

Terminal "Sh" is connected to a similar terminal of the relay-regulator. Through it, voltage is applied to the excitation coils.

Terminal "M" (ground) is connected to the body (minus) of the tractor, and in parallel - to the terminal "M" of the relay-regulator. Terminal "M" of the regulator is also connected to the tractor body. A voltmeter installed on the instrument panel of the tractor to monitor the voltage in the on-board network can be connected to the circuit between the “Sh” and “M” terminals of the voltage regulator.

Some models additionally have a “D” terminal to which the starter relay is connected to block the starter from turning on while the engine is running.

On an idle engine, the current from the battery is supplied to the “Sh” terminal, which is connected to the excitation winding, which creates the initial electromagnetic field. When starting the tractor engine, the rotation from the crankshaft is transmitted through the V-belt to the generator pulley rigidly fixed to the rotor shaft. During rotation, the rotor rotates the electromagnetic field of the shunted excitation windings, which, interacting with the stator windings, creates an alternating electric current on them. The current has peak values ​​at the moment of passage of the protruding parts of the rotor past the stator windings. To equalize the pulses, the generated current from the stator passes through the rectifier, converting to direct. The outputs of the rectifier diodes are connected to the "+" or "B" terminal of the generator, from which the output voltage is taken to charge the battery and power the tractor's electrical appliances.

At the same time, the relay-regulator keeps the current within 14 - 15 volts, for the correct operation of the devices and to avoid overcharging the battery.

When the engine reaches high speed, the generator generates a current that exceeds the nominal value. Passing through the winding of the regulator relay (in the old version), or through transistors (in the modern version), the current, if the values ​​are exceeded, enters the resistance block, which reduce the strength of the electromagnetic field of excitation, as a result of which the current decreases.

Preventive Maintenance

Generators mounted on MTZ tractors have a simple and reliable design, which allows them to work for a long time in difficult conditions, such as dust, exposure to high temperatures, moisture, long-term operation at high speeds.

Systematic preventive maintenance is necessary for the smooth operation of the device. When servicing, it is necessary to check the condition of the generator mounts and the tension of the drive belt. The deflection of the belt with a force of 3 kg / cm should not exceed 3 cm, otherwise the belt should be tightened. The belt must not have tears, cracks, or other signs of damage.

Electrical connections are checked for the quality of fastening and the absence of traces of oxidation. If there is oxidation of the output terminals, disconnect the battery, remove the terminals from the generator and clean. Terminals that are energized must have protective caps that exclude the influence of environmental factors and prevent short circuits.

The serviceability of the device is checked every time the engine is started using the battery charge control lamp. When the ignition is turned on, the lamp should be on, and go out as soon as the engine is started. It is assumed that the lamp goes out only with an increase in the crankshaft speed to 1400 rpm, since some models have an excitation speed higher than the engine idle speed.

If the test lamp does not go out or instrumentation on the panel, such as an ammeter or voltmeter, show a discharge (for a voltmeter, these values ​​\u200b\u200bare lower than 12.5 volts), it is necessary to diagnose the generator. This is only done with the engine off.

Diagnostic procedure

1. Check alternator belt tension. With insufficient tension, the belt can slip under load, and not give the generator sufficient speed.
2. Connect the "minus" from the battery to the "M" terminal, and the "plus" to the "B" terminal. If at the same time the battery charge control lamp is on, this means that the rectifier is faulty (closing diodes, insulation breakdown, shorting the positive terminal to the generator housing).
3. Connect the “minus” from the battery to one of the AC terminals, and the “plus” of the battery to the “B” terminal of the generator. The control lamp should not light up. If the lamp is on, the direct polarity rectifier diode (or several) is broken.
4. Connect the “plus” from the battery through a test lamp to one of the alternating current terminals of the generator, and the “minus” of the battery to the “M” terminal. If at the same time the control lamp is on, this indicates that the reverse polarity rectifier diode (or several) is broken, or there is a short circuit in the stator winding to the generator housing.

TRACTOR GENERATOR T-130M

The generator serves as a source of electrical energy. Its rated power is 1000 W, the rated voltage is 14 V (Fig. 98).

Generator device. The generator, which is a non-contact five-phase same-pole machine with one-sided electromagnetic excitation with a built-in rectifier and voltage regulator, consists of a rectifier unit 3 (BPV 12-100), a stator 5, a rotor 24, front 7 and rear 5 covers, an excitation coil 23, a pulley 10 and impellers 27 for cooling the rectifier.

The stator 6 is a charge, made of sheet steel, has ten teeth, on which coils of a five-phase winding are fixed. The coils are connected in series.

Rotor 24 is a package of a six-beam star, laminated from sheet steel pressed onto the shaft.

A neck and two paws are welded to the front 7 cover, one of which serves to adjust the belt tension, the second to mount the generator. In the front 7 and rear 5 covers of the generator there are ball bearings 22, 25 of a closed design that do not require addition or replacement of lubricant during the entire service life.

Excitation coil 23,
which is a steel sleeve with a flange and winding, located in the front cover. The ends of the winding with lugs are brought out through the stator, the back cover and the rectifier housing and are connected one to the additional output of the generator, the other to the terminal Ш of the voltage regulator.

The rectifier unit 3 (BPV 12-100) consists of a power (main) and additional rectifiers, a voltage regulator unit 1 and a seasonal voltage adjustment switch ("winter - summer"). The power and additional rectifiers are mounted in one housing, and the voltage regulator unit and the seasonal adjustment switch are located on the cover 28 of the rectifier.

The body and plate of the main rectifier are cast from aluminum alloy. The plate is isolated from the body with an insulating gasket and is attached to it with five bolts. The rectifier housing has five holes for the passage of five phase terminals of the stator winding 6 and excitation winding terminals 23. Five diodes of reverse polarity are attached to the rectifier housing, five diodes of direct polarity are attached to the plate. The outputs of the diodes of direct and reverse polarity are connected in pairs by bars with the outputs of the phase windings of the stator.

The additional rectifier consists of three diodes of direct polarity, which are pressed into the bars, connecting in pairs the diodes of direct and reverse polarity of the power rectifier. This rectifier provides automatic protection of the battery against discharge to the excitation winding of the generator when the engine is not running.

Integral Regulator Block 1
voltage is located on the steel cover of the rectifier and consists of a housing molded from glass-filled thermoplastic, an integrated device 35 (IU) with a radiator, a winter-summer seasonal adjustment switch resistor, a filter capacitor 40, a boost resistor 39 to improve self: excitation of the generator.

The integrated device has four outputs C, B, W, D in the form

pads isolated from its base and output M (minus), which is the base of the DUT. The design of the IU is non-separable. The base of the DUT has an orienting tab to prevent it from being installed incorrectly.

Electric energy on MTZ and YuMZ tractors is used to start the engine, lighting, signaling, monitoring the operation of individual systems, and powering auxiliary equipment.

Generator sets (main source) and storage batteries (backup source) serve as current sources. Current sources and consumers are connected in parallel. The connection is made with one wire, which is "positive" (+), the other conductor is the metal parts of the tractor ("ground").

Accumulator battery. Lead-acid batteries are used on tractors, consisting of batteries connected in series with a nominal voltage of 2 V each. Currently, batteries with a nominal voltage of 12 V of various capacities are used. Tank 1 (Fig. 5.1) is divided by partitions into sections according to the number of batteries in the battery. In each section, on the supporting prismatic ribs 12, blocks of plates are installed, consisting of a half-block of negative 8 and a half-block of positive 10 plates. The plates are cast from an alloy of lead and antimony in the form of a lattice. The lattice cells are filled with active mass: for the positive plates - from lead dioxide (brown), for the negative ones - from pure spongy lead (gray).

Plates of the same polarity are welded to the bars 9, which also serve to drain the current. The plates of the semi-blocks are separated by separators 11 made of an insulating and acid-resistant material. Tank sections are filled with electrolyte (25-35% solution of chemically pure sulfuric acid in distilled water).

The cover 4 has holes for outputting the terminals (pins) of the semi-blocks and for filling the electrolyte and controlling its level. As a rule, the electrolyte filling hole is closed with a plug with a vent hole through which the gases released during battery operation exit. In some covers, the ventilation holes are made in the form of a fitting 6. In this case, there is no ventilation hole plug and, when filling the electrolyte, it is installed on the fitting 6, which allows you to automatically set the required electrolyte level, since there is a guide insert in the filler neck, lowered to a predetermined depth. The battery is connected to the battery by jumpers 5.

From the extreme batteries of the battery, terminals are removed to which consumers of electricity are connected.

When the battery is discharged, the active mass of the positive and negative plates, interacting with the electrolyte, turns into lead sulfate. This reduces the concentration and density of the electrolyte, the voltage of the battery (a change in the density of the electrolyte in the process of discharging by 0.01 g/cm 3 corresponds approximately to a decrease in battery capacity by 6%).

When the battery is charged, when it is connected to a direct current source, a reverse chemical reaction occurs - the lead sulfate of the positive plates is gradually converted to lead dioxide, the lead sulfate of the negative plates is converted into pure spongy lead (the density of the electrolyte increases).

The processes of charging and discharging the battery are reversible, so it can be repeatedly charged and discharged.

Genset - it is a kit consisting of an alternator, a rectifier and a relay-regulator or voltage regulator. The tractors in question are equipped
non-contact generators of the G304, G306, 13.3701, 46.3701 and 544.3701 types with built-in rectifiers designed to work with a contact-transistor relay-regulator RRZ62-B, a contactless relay-regulator RRZ62-B1 or with a built-in integrated voltage regulator type Ya112B.

Alternator G304 installed on YuMZ-6 and MTZ-80, MTZ-82 tractors until 1976. The generator consists of stator 1 (Fig. 5.2), covers 3 and 9 of rotor 2 and a rectifier with output 10. The stator is assembled from thin sheets of electromechanical steel, insulated from one another with varnish, which reduces the heating of the stator by eddy currents. It has nine poles with winding coils. Each winding phase consists of three coils, the ends of which are connected to a rectifier. On the back cover 9 there are two pads: one with DC terminals, marked with the letters "SH" (shunt); "B" (rectifier), "M" (ground), the other - with a clamp "-" (alternating current).

Rotor 2 is made of sheets of electrical steel in the form of a six-pointed star and is pressed onto a shaft that rotates in two ball bearings 6, front 3 and rear 9 covers. The excitation coil 4 is a bushing with copper wire windings pressed onto the shaft. The beginning of each winding is soldered to the sleeve, and the ends are brought out to the "Ш" terminal.

Rectifier block consists of a ribbed aluminum housing fixed to the front cover of the generator. The case contains three semiconductor diodes of reverse polarity, which are connected to the ground, and three direct conduction diodes are isolated from it. The outputs of the diodes of direct and reverse polarity are connected in pairs in phases and brought to the terminals. The positive pole of the rectifier is brought out of the diodes of direct polarity to the "B" terminal, and the negative pole - to the "ground".

Alternators G306 and 13.3701. The G306 generator has been installed on the MTZ-80 and MTZ-82 tractors since 1976, and the 13.3701 generator has been installed on the YuMZ-6KM and YuM3-6KL tractors. The alternator G306 consists of a stator 5 (Fig. 5.3) with coils of a three-phase winding, a rotor, front 9 and rear 3 covers of the rectifier unit 11 and a pulley 12 with an impeller.

The rotor (inductor) made in the form of a six-beam star 6 is mounted on the shaft 15 and rotates in bearings 14 and 18, which are not serviced during operation.

The front cover 9 is steel with paws for mounting the generator and tensioning the drive belt. Two drainage holes are made in its cylindrical part (for draining condensate and water that can get into the generator). An excitation coil 7 and a rectifier unit 11 are attached to the ends of the cover with bolts 10.

Attached to the back cover 3 is the generator mounting foot and block 2.

Rectifier block consists of an aluminum case and a heat sink, as well as six semiconductor diodes (valves). Three diodes of reverse polarity (marked with black paint) are pressed into the case, and three diodes of direct polarity (marked with red paint) are pressed into the heat sink. The heat sink isolated from the body is connected to the output terminal with a mounting wire.

In the pulley 12 with the impeller of the axial fan, three threaded holes are made to facilitate its dismantling.

Generators of the G304 and G306 types, which have different letter designations at the end of the marking, differ from each other mainly in pulleys, which allows them to be used on engines characterized by different crankshaft speeds.

Alternator 13.3701 It is made on the basis of the G306 generator and has no special differences from it in design, electrical parameters, dimensions and dimensions. For better self-excitation, the rotor hub is made of steel 40 and hardened. In connection with the use of the Ya112B integral regulator, input filter capacitor, additional rectifier and boost resistor, which are located in a single unit (VPV13-3), the design of the rear cover has been somewhat changed. In addition, both ends of the excitation winding in this generator are isolated from the "mass".

Alternator 46.3 701 mounted on tractors YuMZ-6KM, YuMZ-6KL, MTZ-100 and MTZ-102. The generator is made with a built-in voltage regulator, which is single-pole inductor three-phase machine. In addition to the main one, it has an additional rectifier (output "D") with which the battery is prevented from discharging to the excitation winding of the generator in parking lots, and a generator blocking relay is also connected. Self-excitation is provided by permanent magnets.

Rotor 7 (Fig. 5.4) consists of a shaft with a six-beam star pack located on it made of sheet steel, a sleeve - a magnetic circuit 2, a pulley 12 and a centrifugal fan 10. In a special aluminum frame with six beak-shaped protrusions, they are placed and filled between the teeth of the rotor packs magnets.

Stator 8 is a package with nine teeth, on which coils are located (three per phase).

The front cover 14 has a mounting flange and a tension foot. A rectifier unit with additional diodes is installed in the back cover 1. Plastic mesh cover 3 protects the inner cavity from large foreign objects. In the cavity between covers 1 and 3 there is an integral regulator unit 5, and the covers have windows for intake and exhaust of cooling air.

Alternator 544.3701 mounted on MTZ-80 and MTZ-82 tractors. It is an open non-contact three-phase same-pole inductor electric machine with one-sided electromagnetic excitation and a built-in semiconductor rectifier.

The generator rotor is driven by a belt drive from the diesel crankshaft pulley. The rotor is a shaft with a pressed-on six-ray star laminated from electrical steel. A pulley with an impeller is mounted on the output end of the rotor to cool the rectifier unit and the generator.

The rotor shaft rotates in two sealed ball bearings with permanent lubrication. Ball bearings are installed in covers with openings for intake and ejection of cooling
air. On the rear cover of the generator there are output terminals "+", "Sh" and "D". The excitation winding of the generator is installed inside the front cover. The beginning of the excitation winding is connected to the coil body, and the end is brought out by a wire to the "Sh" terminal.

Between the front and rear covers there is a stator laminated from sheets of electrical steel, having nine teeth with coils of a three-phase winding. The coils in a phase are connected in series, and the phases are connected in a delta. The ends of the phases are led to pairwise connected diodes of direct and reverse polarity of the block of semiconductor valves (three diodes with a red mark are led to the "+" terminal, three diodes with a black mark are connected to the case). Three additional diodes of direct polarity (red mark) are connected to the additional terminal "D", which is connected to the starter blocking relay (only for tractors with direct starter start). Terminals "+", "Sh" and a mass wire are connected to the terminals of the relay-regulator of the same name.

The principle of operation of the listed generators is similar (with some difference regarding generators 13.3701, 46.3701 and 544.3701) and is as follows. When the battery is turned on, a direct current enters the excitation winding circuit of the generator (during engine operation, the winding is powered by the generator through a voltage regulator), where a magnetic field is created that magnetizes the teeth of the rotor and stator.

When the rotor rotates in the core of each stator coil, the magnetic flux periodically changes from the minimum to the maximum value, which induces an EMF, as a result of which an alternating electric current arises in the stator phases.

To obtain direct current, a rectifier unit is used, consisting of six valves: the arm with direct polarity valves is connected to the output terminal "B" (+), and with reverse polarity valves - to ground (-).

The above differences in the principle of operation of generators 13.3701, 46.3701 and 544.3701 relate to an additional rectifier device on silicon valves to power the excitation winding of the generator from its phase windings, which is used to prevent battery discharge to the excitation winding of the generator when the "mass" is turned on and the engine is not running. Otherwise, the principle of operation of generators is similar to that described above.

The operation of consumers of electrical energy and the normal mode of charging the battery is ensured by the required voltage level, which is achieved by relay-regulators RRZ62-B, RRZ62-B1 or an integrated voltage regulator. I112B.

Relay-regulator RRZ62-B in fact, it is a voltage regulator, because. the function of the reverse current relay is performed by the rectifier, and the self-limiting of the generator current is ensured by the selection of the number of turns of the winding (inductive resistance of the stator winding).

According to the functions performed, the relay-regulator consists of the following devices: voltage regulation; protect the transistor from possible short circuits in the excitation winding circuit; seasonal voltage adjustment switch - PPR.

The device for voltage regulation (Fig. 5.5) consists of a transistor T, an electromagnetic relay PH, semiconductor diodes D1 and Dg, resistances Ry, Ra, Rt and Rb.

The device for protecting the transistor from possible short circuits in the excitation winding circuit contains a protection relay RZ and a separating diode, etc.

The protection relay has three windings - the main RZo, the auxiliary RZv, the "opposite" main and the holding RZu.

The PPR seasonal adjustment switch is designed to change the regulated voltage within 0.8-1.2 V and consists of an additional winding wound over the main winding of the voltage regulator and a contact device.

The end of the additional winding is connected to the contact disk through an insulating block.

Switching is carried out with a contact screw 5 (Fig. 5.6, b) with a disk, screwing it in until it stops (position "Z" - winter) or turning it all the way out (position "L" - summer). In the first case, the main winding is connected to the body through an additional winding and the voltage rises. For relay-regulators RRZ62-B of later releases, an additional resistor is connected with the PPR switch instead of an additional winding.

The voltage regulator operates as follows. When the engine (generator) crankshaft speed is not high, and the generator voltage has not yet reached the adjustable value, and the electromagnetic force created by the RN regulator winding is not enough to overcome the force of the opposing spring, the RN contacts are open. The base "B" of the transistor through the resistance Rb is connected to the "mass" (with a "minus") in this case, the transistor and through the excitation winding of the generator the excitation current will flow through the circuit: terminal "B" - diode D1 - emitter-collector junction of the transistor - main RZo winding of the protection relay - terminal "Ш" - excitation winding of the generator (OVG) - "mass". When the generator reaches the voltage corresponding to the regulated voltage, the current of the RNO winding increases to a value at which the RH contacts close. The base "B" of the transistor is connected by the RN contacts to the "plus", in this case the transistor is "locked" and the current in the OVG will pass through the circuit: terminal - diode D1 - resistance Ru and Rd - main winding RZo protection relay - terminal "Sh" - OVG - "mass".

The inclusion of resistances Ru and Rd in the OVG circuit will lead to a decrease in the generator excitation current. In this case, the generator voltage decreases, the PH contacts open, the transistor "opens" and the above process is repeated.

The frequency of closing - opening contacts PH is 30-40 periods per second.

At the moment of closing the contacts of the RH, there is a sharp decrease in the current in the OVG circuit, therefore, an EMF of self-induction will be induced in the OVG. To protect the transistor from dangerous overvoltages caused by the self-induction current, a diode Dg is included in the relay-regulator circuit, which, together with the main winding of the RZo, forms the self-induction current damping circuit.

The transistor protection relay operates as follows. When the circuit of the excitation winding is shorted "to ground", the current flowing through the main (series) winding of the RZo increases. In addition, in the event of a short circuit, the auxiliary winding RZv is shunted, the passage of current through it stops, and since it is turned on "against" the main winding, its demagnetizing effect with respect to the magnetic flux created by the main winding disappears. This circumstance, along with an increase in the value of the current passing through the RZo winding, causes an abrupt increase in the electromagnetic strength of the relay, and the contacts of the RZ relay close. The transistor is fed to the base through a separating diode Dr positive potential, therefore, the transistor is "locked", and the short circuit current is turned off. The contacts of the protection relay will be closed up to those legs (they are kept closed by the RZU winding, which receives power through the closed contacts of the protection relay from the “B” terminal), until the short circuit in the excitation winding circuit is eliminated or the ground switch is turned off.

Relay-regulator RRZ62-B1 contactless type works together with the generator 544.3701, which is installed on the MTZ-80 and MTZ-82 tractors. The relay-regulator contains high-speed electronic protection against short circuit, has protection against "polarity reversal" of food and protection at break of "weight". It is made without the use of contact devices and therefore has more stable characteristics than RRZ62-B.

Specifications are similar to RRZ62-B.

In contrast to the relay-regulator RRZ62-B, in the non-contact relay-regulator, only the voltage level corresponding to the season of tractor operation can be regulated, which is carried out using the seasonal adjustment switch (SPR).

Switching is carried out with a contact screw with a disk located in the upper part of the relay-regulator, screwing the screw in until it stops (winter position) or unscrewing it all the way (summer position).

In order to increase the reliability of the operation of generator sets, simplify the design and reduce the cost, generator sets 13.3701 and 46.370 1 were used on the tractors under consideration, which work with integral voltage regulators.

Generator set 13.370 1 (Fig. 5.7) with a three-phase generator G306 is additionally equipped with:

Seasonal switch. adjustment (NDP), with which you can set two levels of regulated voltage (13.6 ± 0.28 V for the "L" position and higher by 0.8-1.2 V for the "Z" position);

An additional rectifier on three silicon valves for powering the excitation winding of the generator from its phase windings (discharging the battery to the excitation windings of the generator is excluded when the "mass" is turned on and the engine is not running);

Resistor Rp for better self-excitation of the generator.

These devices, as well as the Ya112B regulator and the Sf input filter capacitor (K50-ZA type) are located in a single BPV13-3 unit on the rear cover of the generator, closed with a steel cover.

The Y112B integrated voltage regulator has four outputs with terminals "B", "D", "Sh" and "C" and a "-" output, which serves as the base of the regulator, as well as an orienting protrusion, the use of which eliminates incorrect installation of the regulator.

The terminal "B" of the regulator is connected to the "+" terminal of the generator, "D" - to the terminal "D" of the generator, "Sh" - to the excitation winding, and the terminal "C" - to the capacitor Cf and the resistor of the seasonal voltage adjustment unit.

The generator set is connected to the electrical circuit with output terminals (plus the power rectifier) ​​and (plus the additional rectifier), and the body (minus the generator) is connected to the body ("ground") of the tractor. The starter blocking relay RB1 is connected to the output terminal "D".

Starter - it is an electric motor with a drive mechanism and a switch used to start a diesel engine or a starting motor.

The electric starter motor is a four-pole DC electric machine with a series excitation winding. Shaft 1, armature 4 (Fig. 5.8) rotates in three plain bearings pressed into covers 10, 18 and the middle support disk 12. Brushes 8, mounted in brush holders on cover 10, are pressed against the collector 7 by means of a spring.

A drive is installed on the armature shaft. Drive clutch 2 transmits torque in only one direction: to the engine crankshaft, providing automatic disengagement of the starter shafts in the engine after starting. The electromagnetic traction relay 13 is designed to engage the drive gear with the engine flywheel ring and connect the starter to the battery.

When the starter is turned on, the traction relay through the lever 16 moves the drive along the helical splines of the shaft and engages the gear 17 with the flywheel crown, and then turns on the starter power supply circuit. After the traction relay is turned off under the action of the return spring 15, the drive gear 7 will disengage from the flywheel crown, the main contacts of the relay will open and the starter will turn off.

Distinctive features of other types of starters used on the tractors under consideration (including starters for starting engines) are overall dimensions, weight, power and design of the collector-brush assembly.

Additional electromagnetic starter relays. To ensure timely automatic shutdown of the starter after starting the engine (especially when starting the diesel engine directly with a starter), two additional relays are included in the starter circuit to exclude the possibility of turning on the starter when the engine is running: an intermediate RS502 relay is included in the blocking relay RB1.

The RS502 relay is an electromagnetic relay with normally open contacts, and the RB1 relay, which is affected by the generator current, is an electromagnetic relay with normally closed contacts and a rectifier bridge of four D226D brand diodes.

When the starter is turned on by setting the VK316-B switch to the engine start position, the voltage from the battery through the switch is supplied to the RS502 relay winding, connected to ground through the contacts of the RB1 relay. The PC502 relay is activated, its contacts close, and through them power is supplied to the starter traction relay. The starter turns on and rotates the crankshaft of the engine. With an increase in the frequency of rotation of the engine crankshaft, the voltage supplied from the generator to the rectifier of the relay RB1 increases, and, accordingly, the rectified voltage applied to the winding of the specified relay.

When the generator reaches a voltage of 9 - 10 V, which corresponds to 650-750 min -1 of the engine crankshaft, the blocking relay is activated, opening its contacts, while the PC502 relay is de-energized, its contacts open under the action of the spring and turn off the starter. During the entire time of engine operation over the entire range of its operating speed, the blocking relay contacts are open, which makes it impossible to turn on the starter when the engine is running.

In order to reduce the engine start time when the ambient temperature drops, electric torch air heaters are used on engines of the D-240 type (see clause 2.1.6). After starting the engine, simultaneously with the automatic shutdown of the starter, the solenoid coil is turned off, the valve closes, and the fuel supply to the coil stops. The spiral is turned off when the key is moved to its original off position.

Connection diagrams for starters, taking into account the additional relays and heater described above, are shown in fig. 5.10 and 5.11.

The winding of the traction relay of the starter of starting motors is connected to the battery directly by switch 9 or through an additional relay PC502.

To start the diesel engines of the considered tractors of the YuMZ and MTZ families, starting carburetor engines are used with an autonomous system for generating an electric spark on the spark plug electrodes from a magneto (see paragraph 2.6.1). The safety of starting a diesel engine is determined by the presence and serviceability of blocking devices.

Blocking devices for starting a diesel engine. To exclude the possibility of starting a diesel engine with the gear engaged, on the considered tractors equipped with a starting system, special blocking devices are installed using the starting engine, which turn off the magneto by shorting the primary winding of the magneto transformer to ground.

The blocking device of the MTZ-80L tractor consists of a frame 2 (Fig. 5.12), controlled by a lever 1. frame roller 3, an electric switch 4 of the VK-403 type installed in the gearbox cover,

shims 5 and electrical wiring connecting the switch to the magneto.

The VK-403 switch is normally open and when the KP control lever 1 is set to the neutral position, the frame 2 and the frame roller 3 are installed so that the ball of the switch 4 falls into the hole made on the roller. In this case, there is no effect on the contacts of the switch 4, and they will remain open and starting the diesel engine will be possible. At all other positions of the lever 1, the switch contacts are closed, connecting the primary winding of the magneto with the "mass" and thereby preventing the engine from starting. Similar devices are installed on YuMZ tractors.

The blocking device for starting a diesel engine with a direct start by a starter interrupts the electrical connection between the PC502 relay and the starter traction relay when the position of the gearbox control lever deviates from neutral (example: MTZ-100 and MTZ-102 tractors).

The presence and connection of other consumers of electrical energy can be seen from the electrical equipment diagrams (Fig. 5.9, 5.13, 5.14).

Basic data on the electrical equipment of tractors are given in Table. 34.

Unified tractor generator 46.3701

General information. Generator 46.3701 is designed for tractors and self-propelled agricultural machines. Its power is 0.7 kW, and it is made with a built-in voltage regulator.

The presence of a powerful power source on the tractor makes it possible to solve a number of problems to improve the working conditions of the tractor driver and increase labor productivity ei.

Generator 46.3701 has several modifications that differ in the size of the drive pulley. So, for example, the modification generator 54.3701 is installed instead of the G306 generator.

On a unified generator, in addition to the main rectifier, there is an additional one (terminal D), with which the battery is prevented from discharging to the excitation winding of the generator during stops, and a starter blocking relay is also connected.

Generator 46.3701 has reliable self-excitation due to the use of permanent magnets. The loss of residual magnetization is excluded. Self-excitation is provided with a connected rated load, which makes it possible to carry out agricultural work even in the absence of a battery on the tractor.

A decrease in specific metal consumption or an increase in specific power by a factor of 1.75 was obtained as a result of the use of circulating cooling similar to automobile generators. From the ingress of large particles, the internal cavity of the generator is protected by a plastic mesh cover on the air intake side. The cover is easily removable, and it must be removed periodically (once a season) to remove particles accumulated under it.

Efficient cooling of bearing units significantly increases the life of the generator.

The generator device is shown in Figure 1. It is a single-pole three-phase inductor machine.

The rotor consists of a shaft with a six-beam asterisk made of sheet steel, a magnetic core bushing, a pulley and a centrifugal fan located on it. Magnets are cast in a special aluminum frame with six beak-shaped protrusions placed between the teeth of the rotor packs.

The stator is a package with nine teeth, on which coils are located (three per phase). The cover on the drive side is steel with a welded flange on the fan side. The flange has mounting and tension paws. This cover contains a sleeve-ka-magnetic circuit with an excitation winding. A rectifier unit with three additional diodes is installed in the aluminum cover on the side opposite to the drive. A plastic mesh cover with holes for electrical outlets covers the end of the aluminum cover.

Rice. 1. Generator 46.3701:
1- back cover; 2 - poropa sleeve; 3 - cover of the regulating device; 4 - bearing; 5 - block; 6 - coupling bolt; 7 - rotor; 8 - stator; 9 - excitation coil, 10 - fan; 11 - bearing cover; 12 - pulley; 13 - bearing; 14 - front cover.

Both bearing caps have openings for intake and exhaust of cooling air. Bearing 6-180603 is installed in the cover on the drive side, and bearing 6-180502 is installed on the opposite side. In the cavity between the aluminum and plastic covers there is an integral regulator block.

The alternator is held together with three bolts. Unlike the generator 13.3701 (G306), all electrical connections are inside. Figure 110 shows the electrical connection diagram of the 46.3701 generator; it practically does not differ from the 13.3701 generator circuit.

Generator installation. The connecting dimension between the paws is 90 ± 0.4 mm, which allows, if necessary, to install the generator instead of the generator 13.3701. Other overall and connecting dimensions are the same as for 13.3701 and G306. Generator 46:3701, when delivered as spare parts, has a foot spacing of 130 mm. The paws of the rear cover of the generator are fixed with a longer bolt with nuts installed on it or a special split sleeve in the hole of the rear paw, which can be mixed in the axial direction.

Figure 3 shows the options for mounting the generator on brackets 90 and 130 mm in size.

The generator is not installed on the cast bracket of the D-245 diesel engine,

since the side wall of the bracket prevents the generator from turning when putting on the belt. You need to either modify the bracket or replace it with a bracket of a different size.

When servicing the generator, it is necessary to monitor the reliability of all fasteners, the tension of the drive belt, its general serviceability and cleanliness. Dust and dirt are removed with a brush or a damp cloth.

The serviceability of the generator is checked before starting work using a warning lamp installed on the instrument panel. If the generator is in good condition, the lamp lights up when the "ground" switch is closed before starting the diesel engine. After starting, the control lamp goes out. Having stopped the diesel engine, it is necessary to open the “mass” switch (the control lamp goes out).

On the tractor, the serviceability of the generator is checked only when the diesel engine is not running, by disconnecting the wires from all generator terminals.

The test is carried out using a 12 V lamp and a battery.

When checking the excitation winding, the negative terminal of the battery is connected to the generator terminal M, its positive terminal is connected through a test lamp to the generator terminal Ш. If the excitation winding is working, then the lamp burns half-heartedly (current strength 3.0 ... 3.5 A). The full glow of the lamp (current strength more than 3.5 A) indicates a short circuit between the excitation winding and the generator housing. If the lamp does not light, there is a break in the excitation winding.

The serviceability of the rectifier and stator windings is checked in the following order.

Rice. 2. Electric circuit of the generator 46.3701.

Rice. 3. Generator installation diagrams. 54.3701:
1 - generator; 2 - adjusting washers; 3 - bolt M10 X 55; 4 - bracket; 5 - bolt; 6 - nut No. 110.

1. The negative terminal of the battery is connected to the M terminal of the generator, and its positive terminal is connected through a test lamp with terminal B. In this case, the lamp should not light. If the lamp is on, this indicates the following rectifier malfunctions: short circuit in one or more diodes of both polarities; insulation breakdown between the heat sink and the rectifier case; shorting the positive terminal to the generator case.

2. The negative terminal of the battery is connected to one of the alternating current terminals of the generator, and its positive terminal is connected through a test lamp to terminal B of the generator. In this case, the lamp should not burn. Otherwise, one or more straight polarity diodes are broken.

3. The positive terminal of the battery is connected through a test lamp to one of the alternating current terminals of the generator, and its negative terminal is connected to the M terminal of the generator. The lamp also should not burn. If the lamp lights up, it means that one or more diodes of reverse polarity are broken or a short circuit of the stator winding to the generator housing has occurred.

TO category: - MTZ-100 and MTZ-102 tractors

Generator - an electrical machine that converts the mechanical energy of the prime mover into electrical energy. The generator is used to supply consumers with electrical energy and charge the battery at a certain speed of the engine crankshaft.

The generator is driven from the crankshaft by a V-belt transmission with a constant gear ratio, so the generator speed is directly dependent on the engine speed. And since the frequency of rotation of the crankshaft for tractor engines can vary from minimum to maximum in a ratio of 1: 3.5, and for automobile engines even more (without regulators up to 1: 8), regulators are installed at the generator terminals to maintain voltage within the specified limits voltage.

Since tractor generators operate in more difficult conditions than automobile generators (significant dustiness of the environment, strong vibrations, etc.), they are made closed: their internal cavity is protected by blind covers; heat is removed mainly through the surfaces of the housing and covers. For better cooling, external fans are used.

Automotive generators are made in a protected design - the air flow created by the fan passes through the interior of the case and special windows in the covers, intensively cooling the heated parts.

Generators are characterized by the type of current, voltage, power, initial (without load), at which the rated voltage is reached, and maximum (under load) speed.

Three-phase synchronous alternating current generators with electromagnetic excitation are installed on tractors and cars. Their magnetic field and the rotor rotate at the same frequency - synchronously. The main magnetic flux is generated by the excitation winding connected to the battery, or by the stator windings (supplied through a rectifier). It is also possible to operate the generator with a pre-magnetized magnetic system. The stator coils form a three-phase winding connected in a star, less often in a triangle.

Distinguish generators of contact and non-contact types.

In a contact generator, the excitation current is supplied to the rotor winding through slip rings and brushes. Unlike DC generators, sparking does not occur here, since the rings and brushes do not perform the functions of switching current. In contactless generators, there are no slip rings, brushes and rotating windings; they are highly reliable and withstand harsh operating conditions, but in terms of dimensions and weight they are somewhat larger than contact-type generators.

To charge the battery and power some consumers require direct current; some consumers can operate both on direct and alternating current. In autotractor electrical equipment, rectification of the generator current is adopted, for which rectifiers are provided, usually built into the generator.

Alternators are distinguished by their ability to charge the battery at low engine idling speed. The relatively high frequency of rotation of the generator in this mode allows it to develop sufficient power, thereby freeing the battery from work. For DC generators, the nominal armature speed is limited by sparking under the brushes; when the engine is running at a low speed, the generator voltage is less than the battery voltage, and the current generated by it enters only the excitation circuit and the winding of the relay-regulator.

The installed power of the generator is determined depending on the traction class of the tractor or the load capacity of the vehicle and is 200-1000 W.

Alternating current generators with electromagnetic excitation and contact device. On cars (GAZ-53A, ZIL-130, KamAZ, MAZ, KrAZ, etc.) and some tractors (for example, K-701), three-phase synchronous alternators (G250, G271, G272, etc.) are used with electromagnetic excitation and contact device. The generators are made according to a single scheme and differ mainly in design features and electrical characteristics.

Rice. 1. Generator G272: 1, 12 - covers; 2 - contact rings; 3 - brush holder; 4 - spring; 5 - brushes; 6 - pole pieces; 7 - impeller; 8 - pulley; 9 - shaft; 10, 19 - ball bearings; 11 - bushing; 13 - stator; 14 - excitation winding; 15 - stator coil; 16 - clamp; 17 - ends of the excitation winding; 18 - rectifier block.

The G272 generator of KamAZ vehicles consists of a stator 13 (Fig. 1), a rotor, covers 1 and 12, a contact device, a rectifier unit 18, a drive pulley 8 and other elements.

The stator core is assembled from sheets of electrical steel in a package with 18 teeth evenly distributed around the circumference and fixed with screws between aluminum alloy covers 1 and 12. Eighteen winding coils 15 are placed on the teeth, fixed in the grooves of the stator with textolite wedges. The coils are wound with wire with a diameter of 1.16 mm (eighteen turns) and form three phases connected by a star. Each phase includes six coils connected in series, the ends of which are connected to three clamps 16 of the rectifier unit 18.

The rotor consists of a shaft 9, slip rings 2, two pole pieces 6 of the sleeve 11 and an excitation winding 14. The pole pieces are steel, six-pole, northern ( N) and southern ( S) polarity. The arrangement is such that tips of one polarity move between tips of opposite polarity. Between the pole pieces there is a bushing 11 of the excitation winding 14 containing 1490 turns of wire with a diameter of 0.51 mm. The rotor rotates in ball bearings 19 and 10 (closed type, not requiring lubrication) installed with outer races in the generator covers. Thanks to the impeller 7 on the pulley 8 and slots in the covers for cooling the generator, flow ventilation is created.

The contact device is formed by two copper slip rings 2, a brush holder 3, two graphite brushes 5. pressed by springs 4 to the slip rings. The ends 17 of the excitation winding 14 are soldered to the rings isolated from the shaft. One (isolated from the mass) brush is connected to the clamp W generator, and the second through the generator housing - with a mass.

The cover 1 has a built-in semiconductor rectifier unit 18 of six silicon diodes connected in a bridge circuit. On the cover from the side of the rectifier, negative and positive clamps isolated from the mass are brought out. Positive clamps of direct polarity diodes placed on a panel isolated from the ground are connected to the positive clamp by a contact plate; the negative terminal grounds the contact plate of the reverse polarity diodes.

Maintenance of the G272 generator (for example, KamAZ vehicles) consists primarily in cleaning its generator from dirt, checking the tension of the drive belt, tightening the generator mounting bolts and the pulley mounting nut (TO-1). During TO-2, the tightening of the generator coupling bolts and the condition of the contact wire connections are checked. After 50 thousand kilometers (25 thousand kilometers for a new car), remove the brush holder 3, check the free movement of the brushes in the guide holes, inspect and, if necessary, clean the contact rings 2, test the elasticity of the springs 4. Replace the brushes if their height is from the reference plane springs less than 8 mm.

Non-contact inductor alternators with electromagnetic excitation.
A number of tractors are equipped with closed contactless three-phase inductor alternators of types G304, G305, G306 with built-in rectifiers. Generators G304 and G305 are unified in terms of basic details and differ mainly in winding data. A characteristic feature of these generators is the absence of brush contacts and rotating windings.

The G306 generator, which belongs to the advanced contactless alternators with electromagnetic excitation, consists of a stator 5 (Fig. 2, but) with winding 7, rotor 6, rear 3 and front 9 covers, excitation winding 8, rectifier unit 10, pulley 11 with impeller and mounting feet.

Rice. 2. Generator G306: but- device: 1 - output terminal bolt; 2 - insulating block; 3 - back cover; 4 - coupling bolt; 5 - stator; 6 - rotor; 7 - stator winding; 8 - excitation winding; 9 - front cover; 10 - BPV-30 rectifier unit; 11 - a pulley with an impeller; 12, 15 - ball bearings; 13 - rotor bushing; 14 - bar; 16 - hind leg; b- electrical diagram: OV- excitation winding of the generator; OS- generator stator winding; VP- rectifier: 1 - diodes of direct polarity; 2 - reverse polarity diodes; BUT- ammeter; VM- mass switch; H, W, M- output terminals; T- transistor; E- emitter; TO- collector; B- base; D1- blocking diode; Dg- quenching circuit diode; dr- separating diode; RZ- protection relay; FZy- holding winding of the protection relay; P3o- series winding of the protection relay; RZv- counter winding of the protection relay; RN- voltage regulator; PPR- switch (screw) for seasonal voltage adjustment; PHO- voltage regulator winding; Rb- transistor base resistor; Rt- temperature compensation resistor; Ru- accelerating resistor; Rd- additional resistors.

The stator 5 is assembled from sheets of electrical steel assembled in a package. On the nine teeth of the stator, evenly distributed along the inner circumference, nine coils of a three-phase winding are put on. Coils made of wire PEV-2 with a diameter of 1.35 mm with enamel insulation and double coating have twenty-eight turns and are fixed on the teeth with fiberglass wedges. Each winding phase consists of three coils connected in series. The phases are connected in a triangle (Fig. 2, b). Phase ends of the stator winding OS brought to the bolts 1 (Fig. 2, b) AC terminals placed on the insulating block 2 of the rear cover 3 and marked with a "~". The rectifier leads are connected to the same terminals. VP.

A six-pointed sprocket is mounted on the rotor shaft, assembled from sheets of electrical steel, which are connected with rivets. The rotor is supported by ball bearings 12 and 15 of closed type. The front cover 9 is steel, a field winding coil 8 is bolted to its end on the inside, wound on a steel frame. The winding is made of 500 turns of PEV-2 wire with a diameter of 0.74 mm. The beginning of the winding is connected to the generator ground, and the end is connected to the terminal W. placed on the block 2 of the back cover 3. The cover 3 attached to it is cast from an aluminum alloy. Terminals with their designations are placed on the end mouth of the cover. Two paws are welded to the front cover for mounting the generator and adjusting the tension of the drive belt.