DIY repair of the t 25 generator

Like any other type of transport, a tractor is a complex mechanism with its own characteristics of the chassis, ignition and power systems, as well as electrical equipment. The latter includes many components, one of which is the generator and associated mechanisms.

The generator is a power source for maintaining the operation of the tractor's electrical devices. In order to do its job well, the generator must be simple in configuration and operation, reliable, have a long service life, and small dimensions.

There are two types of generators - alternating current and direct current. Generators - alternating current are easy to operate, can be independently regulated and operate without voltage regulators. But the alternating current cannot charge the battery without a rectifier.

For tractors with electric start, it is more expedient to use a direct current generator, which gives, accordingly, a constant voltage.

In generators, the main components are the stator - a housing with a copper wire winding, the rotor - a rotating magnet with alternating polarity and fixed on the shaft. It also includes covers (back and front) and bearings in which the rotor rotates.
There are 6 cores in the middle of the body. Their set is made of iron plates. Copper windings are fixed to the core. Each of them has 63 turns. The ends lead and connect to terminals that are fixed externally. The windings are connected in pairs in three separate sections. All of them are united by one wire connected to the terminal. From her, the wiring is connected to the switch. The other ends are connected to other terminals, to which the lamp wires lead and through the switch are communicated with the total weight of the tractor.

All sections independently feed the lamp assigned to them. In order for the generator to function normally, only lamps with a suitable wattage should be connected.
The working generator has 3 positions. At the first pole, the rotor connects the iron housing and the teeth. At the heart of the second is the connection through the iron of the teeth. And the third position is similar to the first, only the lines of the poles are in opposite directions.
A generator with direct current has the following components: an armature with windings to excite an electric force; inductors, in the magnetic field of which the armature rotates; diodes for current rectification; collector, thanks to which the current enters the external network.

Exciters in generators of this type are magnets consisting of cores with windings, which are connected in series. At the beginning of work, little force is generated in the windings. But in the process of movement of electric voltage, magnetic fluxes increase.
The concept of a rectifier is associated with direct current. Used to charge the battery. In generators, a diode with a semiconductor (silicon, selenium) acts as a rectifier. The current is conducted in one direction.
Constant voltage generation is provided by an automatic regulation system, which is included in the generator set.

Like any mechanism, the generator and its components tend to wear out and break. A malfunction can be reported by an ammeter located on the dashboard and showing the amount of current, which depends on the condition of the battery.

With a charged battery after starting the engine, the arrow on the device deflects to charge, but not for long, because the current decreases to 1-2 A. Before looking for a breakdown, you should check the battery charge, the accuracy and serviceability of the ammeter.This can be easily verified by turning on the headlights with the engine off. The device should show discharging.

If the ammeter does not show a charge when the engine is running, then there may be a breakdown in the generator or relay-regulator. At low engine speeds, disconnect the wires from the terminals, connecting them to each other and increase the speed. If the generator is working properly, then the current will increase.

So, the matter is in the relay of the Tractor regulator. It needs to be adjusted.
The reasons for the malfunction of the generator itself can be the collector - its pollution, wear, as well as dirty or worn brushes. If, after cleaning these parts, stable operation is not ensured, then you need to look for breaks or short circuits of the circuit or windings; oxidation of wires; belt tension; breakdown of rectifier diodes. If noise is heard during the operation of the generator, there may be a foreign object in the device, it may be faulty and the fan or bearings must be replaced.

After detecting a malfunction, the generator should be disassembled.

Wipe off parts containing wires with a cloth soaked in gasoline, blow through and dry. Rinse the rest in kerosene or a special solution.
If the matter is in the rotor, then there may be the following problems: the magnetic properties are lost, the magnet is cracked, the rotor is bent.

If it is necessary to replace the pulley, the washer is bent, the nut is unscrewed and the pulley itself is removed using a puller. Replace and reassemble if necessary.

When changing the rectifier unit, the screws are unscrewed, the cover is removed, the wires are disconnected from the terminal. Next, the field winding wire, the stator leads are removed, the washers and the rectifier itself are twisted from the latter, after which it is replaced.
The rectifier unit can also be removed when replacing the bearing and stator. In addition, the nut is loosened, the impeller is removed, the bolts are removed. Next, a bushing is placed and a metal plate is placed between it and the screw. Then the back cover is removed and, directly, both the stator and the bearing are changed.

After all the replacements, the generator is reassembled in the reverse order.

As mentioned above, the energy of the generator is variable, because it functions when the rotor speed changes. But in order for all tractor systems to work normally, the current must be constant. For this, diodes are installed to rectify the current. A relay is also installed, the generator regulator, it regulates the operation and interconnection of the generator and the battery. The relay regulator connects the charger to the battery when needed, and disconnects it after the battery is charged.

There are also situations when the load on the generator is more than usual (many electrical appliances are included in the tractor), which leads to overheating. To do this, you also need a device that limits the supplied current. All these functions are taken over by the tractor relay-regulator.

• voltage regulator,
• protection relay,
• transistor,
• diodes,
• seasonal switch.

At a low generator speed, the current is generated within the tractor's permissible norm and the relay passes it without resistance to the protection relay. As the engine speed increases, the voltage in the windings increases. Therefore, in order to avoid overloading the electrical equipment, a regulator is triggered, which stabilizes the voltage within a safe working standard. A properly configured relay should trip at 7 V.

There is a concept of seasonal operation of the tractor, therefore there is a winding on the regulator, which is regulated by a screw. If the temperature is higher than 5 ° C, the propeller is switched to the "Summer" mode. Accordingly, the "Winter" mode is activated at low temperatures.
The relay-regulator, like other devices, should be checked from time to time with special devices right on the tractor. It should be removed and opened only in case of special need by qualified specialists.

The set of electrical equipment consists of a storage battery; starter with current switch; DC generator; relay regulator; glow plugs (with a control coil and a switch) or an electric torch heater with a switch; rear and front headlights with electric lamps; a portable lighting lamp with a socket; a sound signal and an ammeter to monitor the operation of electrical equipment. Tractors equipped with a diesel engine with a starting engine without a starter,

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The electrical circuit of the T-25 tractor (Fig. 71) is single-wire, the nominal rectified voltage is 12 volts; the negative terminals of the current sources are connected to the body ("mass" of the tractor).
Before starting the engine with the "ground" switch 6 installed under the instrument panel, the negative terminal of the storage battery 4 is turned on to the tractor body. At the same time, a control lamp 14 with a red cap lights up on the instrument panel. The engine is started by a starter 3 with electromagnetic activation. The starter is turned on by turning the key inserted into the starter switch 13 through the intermediate relay 37.

The starter switch has two positions: the first is to turn on the heater 45 (glow plug) and the second to turn on the starter.
When starting the engine in winter, the duration of the glow plug must be 30-40 seconds. Starter operation when starting the engine should not exceed 10 seconds. If the engine does not start after two or three start-ups with a one-minute break, then you should find out the reasons for the poor start and eliminate them. To automatically turn off the starter when starting the engine and to exclude the possibility of re-turning it on when the engine is running, a blocking relay 43 is provided in the electrical circuit. The battery is charged while the engine is running. In this case, the DC voltage from the output terminals of the generator through the ammeter 34 is supplied to the positive terminal of the storage battery. The negative terminal of the generator is connected to the tractor body by "mass". The charging and discharging current of the storage battery is controlled by an ammeter.

Wiring diagram of the T-25 tractor

A deviation of the ammeter needle from zero to plus indicates battery charging, and a deviation from zero to minus indicates its discharge.
The electric lamp for monitoring the position of the ground switch with serviceable power supply and starting systems and the presence of a generator drive belt goes out when the engine is running. If the warning light comes on while the engine is running, then this indicates either a broken fan belt or a generator malfunction. In this case, it is necessary to stop the engine, disconnect the "ground" and eliminate the malfunction.
Attention:
When stopping the engine, it is necessary to disconnect the battery by turning off the "mass" switch (the control lamp goes out in this case).
Failure to do so may result in battery discharge through the generator field winding.

The T-25A tractor is an excellent choice for your farm. It will greatly simplify the already difficult work in the field.

The T-25 tractor is a wheeled vehicle designed for plowing light soils, light-duty work and use with a mower and other non-self-propelled equipment. It is equipped with rear wheel drive and small front drive wheels. T-25 was assigned a traction class of 0.6.

In 1966, the first T-25 models rolled off the assembly line of the Kharkov tractor plant. In the 72nd year, production was transferred to the Vladimir Tractor Plant. A year later, the T-25 was removed from the assembly line, replacing it with an upgraded version of the T-25A, which is still being produced by the plant today. This model has found wide application in the national economy of the Soviet Union, and now in Russia.

The prototype was the DT-20 tractor, almost completely redesigned by the developers at the Volgograd Tractor Plant. The result is a multifunctional machine for the national economy at an affordable price. Over the entire history of production, more than 800 thousand units have rolled off the assembly line. Due to its small size, the tractor was widely used in the communal sector, together with trailed equipment. For the repair of the T-25 tractor, they continue to use the books of past years.

The version of the T-25A tractor is considered the base model for subsequent changes. On its basis, the T-25A3 with a safety frame and the tilt T-25A2 were developed. These were all the fundamental differences that should be taken into account when repairing the T-25 tractor. Rear-wheel drive and traction class remain the same. The T-30A80 model has undergone significant changes. She became all-wheel drive with a comfortable cab, equipped with a new D-120 power unit and power steering.

1. The first models used the D21A1 engine with a rated power of 20 hp. The modified T-25A received a 25 hp unit. It is an air-cooled, four-stroke diesel engine with an autonomous thermal regulation lubrication system. An electric starter is used to start.
2. The T-25 has a mechanical eight-speed transmission (with two low forward gears), a pendulum hitch and a rear hitch system.
3. The weight of the tractor with an empty tank and without taking into account the load was 1.78 tons.
4. Linear parameters: length - 3.11 m, width - 1.37 m, height - 2.5 m.The track width range varies from 1.2 m to 1.4 m.
5. The specific consumption of diesel fuel at a crankshaft speed of 1800 rpm does not exceed 190 g / hp h.

A significant nuance of the T-25 model range was the presence of a cab heating system powered by the machine's hydraulics. The modernization of the 96th year also affected the heating, which became tied to the lubrication system of the power unit. On all T-25s, the hydraulic system is divided into aggregate units and is equipped with an independent drive part of the hydraulic pump.

The revolutionary solution of those years was the use of a semi-frame base of the tractor, which made it possible to change the track width and agrotechnical clearance. Another feature is considered when repairing a T-25 tractor, setting up work in reverse gears for a long time.

The basis of the multifunctionality of tractors of this type is a large number of non-self-propelled trailed equipment designed for them. The T-25 tractor today is the most affordable technique with a closed cabin.

The cost on the secondary market varies in the range of 50 - 450 thousand rubles. The price of the new one starts at half a million rubles. The T30-69 tractor, widely used in agriculture, and low-power devices from Chinese manufacturers (FT-254, Fengshou FS 240) are considered analogues of the T-25. They all have similar characteristics and are in the same price range.

Tractor T-25 (repair of the T-25 tractor)

The book contains the device and the operating procedure, recommendations for the repair of the T-25 tractor. The issues of car care are covered in detail, recommendations for the most correct use of the tractor in all works are given.
The book is intended for machine operators working on tractors.

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Hello everyone. There is only a generator g302b from t25.I looked at the diagram of how to connect the battery charge, but I didn’t really understand. Generator 4 wires. Maybe someone can tell me what else is missing (diode bridge, chocolate)? How to properly connect all this into a working structure? It was great to see a photo of the parts with the connection. Thanks in advance! bought a tractor for the price of metal. The engine started, but there is nothing from the wiring.

Thanks in advance for any help. :)

Hello everyone. There is only a generator g302b from t25. I looked at the diagram of how to connect the battery charge, but I didn’t really understand. Generator 4 wires. Maybe someone can tell me what else is missing (diode bridge, chocolate)? How to properly connect all this into a working structure? It was great to see a photo of the parts with the connection. Thanks in advance! bought a tractor for the price of metal. The engine started, but there is nothing from the wiring.

Thanks in advance for any help. :)

there, under the torpedo, there should be a regulator relay - winter, summer. and the circuit is not particularly complicated. one wire for control, one excitation, one output for pp, and I don't remember the fourth.

A car generator is a device that takes mechanical energy from an engine and converts it into electric current, thus providing electricity to the rest of the car's units. The generator provides battery charging and power to the vehicle's engine. Therefore, the connection "engine-generator" should not be interrupted, because an inoperative generator is a battery that does not receive a charge and, accordingly, an inoperative main body of the car.
Replacing the generator will entail significant financial costs. Therefore, if you have at your fingertips all the necessary tools and knowledge of the devices of the engine compartment of the car, then you can fix the breakdown yourself (read about what to do if the car does not start - the starter turns, read in our other article).

So the generator is broken. What malfunctions can cause this device to malfunction? Let's consider them:

1. The generator produces a very low voltage current.
2. The generator does not generate electricity at all.
3. A breakdown of the device is displayed on the dashboard in the form of a blinking light.
4. The generator is charging in excess of the optimal rate.
5. Generator operation is accompanied by extraneous noise.

Before you start doing generator repairs with your own hands, it is necessary to check its technical condition and disassemble the unit into parts. Before disassembling the generator, check the condition of the belt and its tension and make sure if you are expecting a replacement of the alternator belt in the near future (read also how the timing belt is replaced with a VAZ 2109). Checking consists in pressing your finger on the middle of this part of the generator. If the belt is in good condition, then it should not fall by more than half a centimeter when pressed. It should be noted that the new belt should not bend more than 2 mm. If the belt is not worn out, but the tension is weak, then the defect can be corrected by tightening the generator belt. Also scroll the generator tension roller, if it scrolls with difficulty and creaks, then it will need to be oiled, or put a new roller instead.

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The technical condition of the generator can be checked using the following measuring instruments:

The rotor speed is measured using a tachometer (usually located next to the speedometer on the dashboard). During normal operation of the generator, the indicators of this device should not be less than 2000 rpm, while the norm is 5000 rpm.

Let's consider the reasons that can cause generator breakdown. So, if the generator does not generate a charge, then the following phenomena may be the reasons for this:

1. Fuse or contacts blown.
2. Broken or worn out generator brushes.
3. The regulator relay is out of order.
4. Due to the short circuit of the winding, an open circuit occurred in the stator or rotor circuit.

In order to fix the first three malfunctions from the list, you just need to replace the worn out parts of the generator, having previously, of course, disassembled it.

1. First of all, remove the brush holder along with the voltage regulator, carefully unscrewing all fasteners.
2. Remove the tensioning bolts and then the cover with the stator.
3. Remove the cover from the stator by first disconnecting the phase windings from the output wires on the rectifier unit.
4. Next, remove the pulley from the shaft and the front cover of the generator using a special puller.

The assembly of the generator is carried out in reverse order.

In the event of a short circuit in the winding, you will need more serious action than a simple replacement of the part. So, a broken winding can either be repaired or replaced with new wires. Often the winding breaks off near the slip rings. In addition, breakdown can occur due to unsoldering of any of the ends of the winding. Such a malfunction can be repaired by rewinding the coil in the area of ​​the gap back from the rotor winding. Further, the broken end of the winding must be removed (evaporated) from the slip ring and the previously unwound wire must be soldered there. The wiring is very easy to repair by re-soldering the wiring.

A weak or too strong generator charge is indicated by a damaged relay, which must be replaced when the generator is repaired.

If the generator voltage check showed that the device is working, but the indicator is flashing on the instrument panel, then, most likely, one of the diodes that are responsible for powering the light in the indicator has failed. These diodes are located in the generator itself, and replacement is carried out after disassembling the device.

Noise unusual for a generator may be indicated by wear of the rotor bearing. If an inspection reveals that the generator bearing is worn out, it will need to be replaced. If the incomprehensible sounds of the generator are associated with the absence of play in the bearing, then it can be simply filled with oil, having previously washed it in gasoline. Extraneous sounds will then disappear.

Thus, you can even repair the generator on your own in your garage (as well as overhaul of the engine, in fact). When checking and replacing parts of the device, observe safety precautions and be careful, because the electrical system should not be damaged in this case.