Heading Electrical equipment of wagons

Contents

Contents

Paper

1 General information about the electric equipment of the car

1.1 Electric Power Consumers

1.2 Electrical Power Sources

1.3 Arrangement of electrical equipment in the car

2 Calculation and selection of main electric equipment of the car

2.1 Calculation of electric lighting

2.2 Calculation of drive motors

2.4 Power Source Power Calculation

2.5 Calculation and selection of wires

2.6 Selection of protection devices

3 Electrical diagram of wagon electrical equipment

3.1 Diagram of electric consumers activation

3.2 Protection and interlock diagram

3.2.1 Overvoltage protection

3.2.2 Thyristor protection

3.2.3 Phase skew protection

3.2.4 Protection against short circuits and overloads

3.2.5 Protection of the storage battery from reduced voltage

3.2.6 Locking systems

3.3 Signaling diagrams

3.3.1 Ringing

3.3.2 Axle box heating monitoring system

3.3.3 Alarm for filling tanks with water

3.3.4 Alarm of wire insulation condition monitoring

3.3.5 Anti-union device

4 Fan motor repair and maintenance technology

Literature

In the discipline "Electric equipment of cars"

ESTABLISHMENT OF EDUCATION

BELARUSIAN STATE UNIVERSITY OF TRANSPORT

Department "WAGONS AND WAGONS"

Calculation and selection of electric equipment and wagon power supply network

Paper

The course work consists of an explanatory note (37 sheets) and a graphic part - 1 sheet of A1 format (a simplified diagram of the autonomous power supply system of a soft car with air conditioning).

The explanatory note includes four sections:

- general information about the electric equipment of the car;

- calculation and selection of the main electrical equipment of the car;

- electric diagram of car power supply;

- technology of heating devices repair and maintenance.

The first section describes the sources and consumers of electric energy of the car, their placement in a soft car with air conditioning (Figure 1).

The second section includes calculation of electric lighting, calculation of power and selection of electric motors, calculation of heaters, calculation of power source, calculation and selection of wires, selection of protection devices. Figure 2 shows the layout of the soft car.

The third section describes the circuits for switching on electric consumers, control and automation circuits, protection and blocking circuits, alarm circuits. The diagrams are described in accordance with the graphic part.

The fourth section describes the repair procedure and technical inspection of the fan motor.

General information about the electric equipment of the car

1.1 Electric Power Consumers

In a soft car with air conditioning with an autonomous power supply system, electric consumers are:

• luminescent lighting converter;

• filament lamp lighting network and signal lights;

• fan motors, refrigerator compressor, condenser fan;

• drinking water cooler;

• electric kiln;

• heating of filling and drain pipes;

• household appliances;

• Alarm and control circuits.

Fluorescent lamps are located:

• in the compartment one lamp (8 pcs.);

• in the aisle - four pieces;

• in a large corridor - one;

• one in a small corridor;

• one in each toilet;

• one in the office room.

In a car with an autonomous power supply system, special transducers are installed to power fluorescent lighting lamps. Emergency lighting of the car is carried out by filament lamps located in the same lamps as the main lighting lamps. This lighting is automatically turned on when the main lighting lamps are energized.

Lighting fixtures with filament lamps are located:

• in tambours, two in each;

• one in the boiler room (utility room).

Signal lights are installed on the end walls of the car - three pieces on each side of the car.

The fan motor is located in the attic room of the car.

The condenser fan motor and the refrigerator compressor motor are located under the car body.

At the beginning of the ventilation channel, a ventilation unit is mounted above the ceiling of the vestibule. Further, an electric heater is located in the ventilation channel.

Electric furnaces are located along the side walls of the car. The housing of the electric network is closed with a casing, in which there are cuts for flowing around the heating elements of air. Electric heating is controlled from the switchboard in the service room.

1.2 Electrical Power Sources

The main source of electric energy in the car is a three-phase alternator of the inductor type DCG - 4435, connected to the wheel pair of the car using a special drive. When the train moves, rotation is transmitted from the wheel pair to the generator, which generates electric energy. At long-term parking, consumers receive electric energy from the station network through a transformer and their own power rectifier.

As a backup source of electric energy, a battery is used that powers the main consumers of the train when the generator is not operating, as well as at a low speed of the train when the generator does not develop the necessary power. Also, the battery perceives load peaks that occur when several high-power consumers are simultaneously switched on, electric engines are started, short-term overloads, etc. We accept battery 82VNZh400.

The generator has an automatic control system that provides the necessary quality of electrical energy.

The car is equipped with a basement electric line and inter-car connections, which allow, when the generator fails on a car, to supply part of the consumers located in it from the electric energy sources of neighboring cars.

1.3 Arrangement of electrical equipment in the car

At the location, the electric equipment of the cars is divided into in-car and sub-car. At the same time, the design of electrical equipment, determined by the method of protection against external climatic and mechanical impacts, is selected in accordance with the place of its installation.

The electric equipment of the car is controlled from the panel of the distribution cabinet located in the service compartment of the car. Electric power sources (generator, battery), compressor motors and refrigerator condenser fans; electric heaters of drain pipes; part of the switching protection equipment, and others are located under the car.

Location of electrical equipment on air-conditioned car

In the ventilation channel there is an electric heater 2, as well as a fan motor 1.

The service room houses the distribution cabinet 3.

Under the frame of the car there is an electric motor of the compressor 14, an electric motor of the condenser of the refrigeration unit 13 and an electric machine converter 11 for fluorescent lighting, a box with control equipment of the refrigeration unit 12, a box with starting resistances of the motors 17, a box 16 for connecting the station network, a three-phase alternator 10 of the inductor type DCG - 4435.

Inside the car there are fluorescent lamps 4, lamps with incandescent lamps 6, electric heaters of filling pipes 18, electric heaters of drain pipes 8, drinking water cooler 19, electric heater 20. Electric furnaces 5 are arranged along car walls.

Signal lights 7 are installed on the end walls of the car.

Calculation and selection of main electric equipment of the car

2.1 Calculation of electric lighting

The value of reflection coefficients is taken to be equal: for pure white ceilings - 0.7, dark matte ceilings - 0.5, white walls with unlocked windows - 0.5, dark walls with unlocked windows - 0.3, light lower working surface - 0.3, dark lower working surface or floor - 0.1.

Based on the required luminous flux, 1 luminaire with two LXB40 lamps with a luminous flux of 2600 lm, with a power of 40 W.

Determine the discrepancy between the required and actual light

Discrepancies between required light and actual flows do not exceed 5%. We finally accept a lamp with two lamps

LHB-40.

Due to the analogous calculation of lighting for all car rooms, for the remaining rooms the results of the calculation are entered in table 1.

We receive the GEUB3 electric machine converter with a nominal generator power of 1.2 kW and an engine power of 1.5 kW.

2.2 Calculation of drive motors

On passenger cars with air conditioning there are electric motors for driving a fan, electric motors of a compressor and a condenser fan of a refrigeration plant, converters for AC power supply of luminescent lighting.

Power of fan motor, kW, is determined by formula

2.4 Power Source Power Calculation

To calculate the required electric power of the passenger car, it is necessary to select the design mode of operation and determine the design and peak currents for this mode.

Design loads mean such constant loads (currents, powers) that cause the same effect on the electrical system (heating of wires, motors, etc.) as actual loads, which continuously vary in magnitude and time. Design loads are determined for the most electrically loaded periods of electrical equipment operation. Summer and winter periods of operation are considered for passenger cars. Since it will be difficult to establish a period in which electricity consumption will be maximum in most cases, the design loads for summer and winter operating modes are found and large ones are taken for subsequent calculations.

In Table 4 we enter the electric power consumers generated by the generator of this passenger car.

Of the two capacities, we choose a large P = 33.26kW.

Based on the required power, we select the generator DCG4435 (alternating three-phase, rated power 35 kW, operating speed range: 10004000 rpm, operating voltage 150 V, weight 720 kg).

2.5 Calculation and selection of wires

We calculate and select the wires that transmit electrical energy from the source to the switchgear. To do this, first of all, you need to determine the length of the wires based on the structural arrangement of the distribution board and the energy source, select the wire tag and how it is routed.

Electrical wiring selection is performed according to four conditions:

- permissible heating;

- permissible voltage loss;

- protection against short-circuit currents;

- mechanical strength.

Under the first condition, the permissible heating must not exceed the permissible value of 55C. The value of the current at which the steady-state temperature value corresponds to the norm is called the permissible current value

Compare the voltage loss in the wires with the allowable voltage reduction

The condition is met.

The electric power circuits of the car have protection against overheating and overcurrent, so the permissible wire current must exceed the nominal protective current

The condition is fulfilled, therefore, the safety and reliability of the wires is ensured.

2.6 Selection of protection devices

Fuses and circuit breakers are used as devices to protect electrical networks from short-circuit currents and significant overloads and duration.

When selecting fuses, the following conditions shall be observed:

• The rated fuse voltage shall be equal to or greater than the rated mains voltage:

Electrical diagram of wagon electrical equipment

3.1 Diagram of electric consumers activation

The power source of consumers in the car is an inductor alternator DCG4435 with a power of 35 kW with one three-phase stator winding. Consumers of the car are fed from the generator through rectifier V2. Storage battery GB is connected to output of rectifier V1 via storage battery charge regulator. At non-operating generator and at train speed below 30 km/h, consumers are supplied from accumulator battery. The generator voltage is automatically controlled by the thyristor voltage regulator of the FGV, which is connected to the generator through the rectifier V1 and changes the current in the parallel excitation winding of the generator. The VGN controller also reduces the voltage of the generator during overloads, ensuring that its current is limited. The filament lamps of the lighting network, the converter for supplying luminescent lighting, control and alarm circuits are supplied from the generator through a diode limiter, which stabilizes the voltage at 110V. At long-term parking, electric consumers are supplied from the stationary network through the step-down transformer T1.

The car is illuminated by fluorescent lamps, which are powered by an electric machine current converter. The DC motor of the converter, connected through a diode limiter to the generator at a voltage of 110V, rotates the shaft of the alternator, which generates current to power fluorescent lamps. The lamps are divided into three groups: the first group of lamps with lamps EL1-EL16 is located in the compartment; lamps of the second group are located:

- toilet on the working side (lamp with lamps EL17, EL18);

- corridors (lamps with lamps EL19-EL22);

- service room (lamp with lamps EL23, EL24);

- toilet on the non-working side (lamp with lamp EL25).

Lamps of the third group with lamps EL26-EL29 are located in the passage.

Switch Q1 switches on and off the supply of voltage to the luminescent lighting network. The network of lamps of the first group is switched on by switch Q2, the second - Q11, the third - Q13, located on the control panel in the service room. Switches Q3 - Q10 are designed for independent disconnection of lamps in each compartment, and switch Q12 - in the service room.

Rectifiers V3-V5 are connected to the luminescent lighting circuit to power contactors K1-K3, which after switching on the luminescent lamps open contacts K1.1-K3.1, turning off filament lamps EL30-EL37, EL38-EL42 and EL43-EL46, respectively. Emergency lighting lamps EL30-EL46 are located inside fluorescent lighting lamps and are designed to illuminate the car at night and in emergency situations. Switches Q14, Q23 and Q25 are used to control filament lamps. Tampes in each compartment can also be turned on and off by switches Q15-Q22, the lamp in the service compartment - by switch Q24.

Lamps EL47-EL54 located in tambours and utility room are actuated by switch Q27. Lamps EL53, EL54 of the utility room are switched off by switch Q28. Signal lamps HL1-HL6 are controlled by switch Q26.

Air conditioning unit - compressor and condenser fan motors - is controlled by air conditioning unit control unit.

The circulation pump motor is switched on by switch QF1.

The engine of the fan system is switched on by switch Q29.1 simultaneously with the control circuit, which is switched on by switch Q29.2. The engine has three speed control stages to change the air supply depending on the temperature inside the car. Engine speed changes by changing armature resistance or motor excitation winding. Upon reaching the t=20˚C, the contacts of the temperature sensors located at the edges and in the middle of the car cabin are closed, which leads to excitation of the coil K5, while the contact K5.1 of the coil K7 circuit is closed, which by contact K7.1 shunts the resistance R4 of the engine armature. Engine speed increases. When the temperature in the cabin t = 22 ° C is reached, the second circuit of temperature sensors closes, passing current through coil K6, which closes contact K6.1 in the circuit of coil K8. Coil K8 opens contact K8.1 and the drive current passes through resistance R5. Magnetic flux decreases and rotor speed increases. When the air temperature in the car decreases, the coils of contactors K6 and K5 are successively de-energized, contacts K6.1 and K5.1 open, which leads to the return of contactors K8 and K9 to the initial position. Contact K8.1 closes and K7.1 opens. The engine changes to a low speed. When the fan is switched on, the signal lamp HL7 comes ON.

The car is provided with cooling of drinking water. The cooler motor is switched on to the network by switch QF2. In case of temperature increase, the temperature sensor KT1 operates and the circuit of the coil K4 is closed, which with contact K4.1 turns on the electric motor of the drinking water cooler.

Electric furnaces of the car are assembled in three groups - EK1, EK2, EK3. The electric heater has two sections EK4 and EK5. Electric furnaces and calorifer are switched on by switch Q30.1 simultaneously with control circuit, which is switched on by switch Q30.2. At a temperature in the car below 18 ° C, all temperature sensors are open, current passes through coil K12, which closes contacts K12.1 and K12.2. Voltage is supplied to electric furnaces and calorifer, HL8 signal light is ON. When the temperature in the cabin reaches 18 ° С, the temperature sensors in the circuit of coil K11 are closed. When the temperature rises to 22 ° С, the second circuit of temperature sensors (t = 22 ° С) closes, passing current through coil K10, which closes contact K10.1. Voltage is supplied to coil K11, as a result of which contact K11.1 is opened, coil K12 is de-energized. Contacts K12.1 and K12.2 are opened. The ovens turn off, the light bulb stops burning. When the temperature drops below 22 ° C, the circuit of thermal sensors t = 22 ° C opens, the coil K11 remains energized (current passes through the circuit of thermal sensors t = 18 ° C). When the temperature drops below 18 ° C, the temperature sensors t = 18 ° C open, relieving the voltage from the coil K10 and K11. The contact of K10.1 is disconnected and K11.1 becomes isolated. As a result, coil K12 comes under voltage, contacts K12.1 and K12.2 are closed, bringing the heating system into operation.

The EK6 heater is switched on using switch SA1. When it is activated, coil K9 is excited. Contact K9.1 and K9.2 are closed. The HL8 signal lamp lights up and the reboiler turns on.

In a bulk pipe the EK7 and EK8 heaters which are turning on the QF3 switch are located.

The car provides for the presence of process sockets, which are switched on using the SA7 switch.

3.2 Protection and interlock diagram

The following protection systems are used in the car:

- overvoltage protection (maximum voltage relay);

- thyristor protection;

- protection against phase distortion;

- protection against short circuits and overloads;

- protection of the storage battery from reduced voltage.

3.2.1 Overvoltage protection

During normal operation, voltage regulator automatically maintains average value of generator excitation current corresponding to its frequency and load. This excitation current value corresponds to the average value of generator voltage and voltage at consumers.

In emergency operation modes associated with the failure of the voltage regulator, automatic control is stopped, and the voltage can increase sharply as a result of a large excitation current. To prevent unacceptable long-term increase in voltage on consumers, special protection is provided.

When the voltage exceeds the permissible voltage, the protection (RMN) breaks the supply circuit of the generator excitation winding, as a result of which the magnetic flux of the machine and the voltage drops.

The maximum voltage relay shall not operate in case of accidental voltage drops when consumers are disconnected. Restore the diagram by pressing the "Return protection" button.

3.2.2 Thyristor protection

This protection protects the system from switching voltage surges in emergency modes when large consumers are disconnected. Thyristor protection performs four actions:

- low-voltage resistances (0.315Om) are connected to the power rectifier clamps using a thyristor, sharply reducing the generator voltage;

- maximum voltage relay is actuated;

- accumulator battery is disconnected from the car network;

- emergency lighting network is switched on by separate wires for half voltage of the storage battery.

Thyristor protection can be artificially activated by pressing the "Emergency" button. The protection scheme is restored by pressing the "Return protection" button.

3.2.3 Phase skew protection

This protection, when one of the generator phases breaks, breaks the supply circuit of the generator excitation winding. Wagon consumers switch to battery power.

3.2.4 Protection against short circuits and overloads

Such protective equipment includes fuses with fuses and circuit breakers. Fuse fuse insert is connected in series to protected circuit. When the nominal current flows, the fusible insert is heated. If the current has increased more than a certain value, melting of the insert occurs and the protected circuit is broken, preventing the equipment from failing.

3.2.5 Protection of the storage battery from reduced voltage

The protection is designed to prevent unacceptable AB discharge. When the SB voltage is lower than permissible, the protection automatically disconnects the wagon consumers from the battery. Only the emergency lighting network remains on.

3.2.6 Locking systems

Interlocks are used to save power. For example, in this power supply system, the heater of the reboiler is disconnected in the parking lot and the fan engine is switched to a low speed, when the fluorescent lamps are turned on, the emergency lighting lamps located in the fluorescent lamps are turned off.

3.3 Signaling diagrams

The following alarm systems are used in the car:

- ringing;

- axle box heating monitoring system;

- alarm of tanks filling with water;

- wire insulation condition monitoring;

- anti-union device.

3.3.1 Ringing

The alarm is used to call the conductor in the vestibule, or in the compartment. The alarm acts as follows.

To call the conductor to the vestibule press SB9 or SB10 button located in the operating and non-operating vestibule. In this case, the circuit of the lamp HL23 or HL24 is closed, respectively, indicating on which side of the car the conductors are called. Simultaneously with the lamps, power, through diodes VD1 or VD2, receives a HA2 call. Diodes make it possible to prevent the illumination of both lamps at the same time. When the button is released, the circuit opens.

To call the conductor in the compartment, press any of the buttons SB1-SB8 located in each compartment, as a result of which one of contactors K16-K23 will receive power respectively and one of contacts K16.1-K23.1 will close. These contacts put their contactor under tension. This causes the alarm to work after the button is released. Through one of the buttons SB1-SB8, or contact K16.1-K23.1 when the button is released, the current is supplied to the signal lamp HL15-HL22, each of which corresponds to its own button and indicates in which compartment the button was pressed. Simultaneously with the supply of voltage to the lamp, one of contacts K16.2-K23.2 supplies current to HA2 call.

3.3.2 Axle box heating monitoring system

The car has a system for monitoring the heating of axle boxes with meltable sensors. If the temperature of one of the letters increases to 90110˚S, the fuse insert of the sensor VK1-VK8 melts, opening the electric circuit. The K13 coil is cut off power and closes contacts of K13.1 and K13.2 that leads to turning on of the HL10 signal lamp and a call of HA1.

3.3.3 Alarm for filling tanks with water

The system is switched on by SA5 switch. When filling begins, one of the sensors E1 or E2 closes. Coil K14 comes under voltage and closes contact K14.1. When the side is filled to a certain level, the sensor E3 closes and supplies voltage to contactor K15. Contactor K15 closes contact K15.1 and passes current to signal lamps HL13 and HL14.

3.3.4 Alarm of wire insulation condition monitoring

The wire insulation condition monitoring system is designed to check the insulation condition between the wire and the car body. When SA3 and SA4 switches are switched on at the same time, the signal lamps HL11 and HL12 light up. When one of the wires is closed to the car body, one of the lamps goes off, and the second begins to burn with full heat.

3.3.5 Anti-union device

Anti-jamming device is intended for detection and termination of wheel pair yoke caused by excessive pressing of brake shoes. When braking starts, contact of pressure switch BP1 connected to the brake cylinder cavity is closed. In case of a suze, one of the contacts of the axial sensors E4E7 is closed for a short time and the coil K24 is powered, which becomes the contact K24.1 for self-supply, and the contact K24.2 supplies power to the coil K25 of the electric air distributor. Coil K25 discharges air from the brake cylinder. The skid stops and the BP1 pressure switch is disconnected, cutting off power contactors of K24 and K25. Air discharge from the brake cylinder stops. The braking process resumes, the contact of the pressure switch BP1 is closed and the circuit is again ready for operation.

4 Fan motor repair and maintenance technology

During periodic repair, the fan motor is removed from the car. By means of crane-beam electric motor is installed on vehicle and delivered to compartment for repair of electric machines.

Electric motor removed from car is cleaned from dirt and dust by compressed air in blowing chamber before disassembly. Electric motor is installed on rotary table of blowing chamber trolley by means of crane beam. The glazed windows of the camera doors are designed to monitor the blowing process. Chamber doors are locked with trolley turntable. A fan is mounted outside the chamber to suck dust and dirt into the dust collector.

Before cleaning with compressed air, protective covers, shields, covers of clamping boxes and manholes of manifolds, etc. are removed from the electric motor. Then motor of trolley travel is actuated and rolled into chamber. Chamber doors are tightly closed, exhaust fan is turned on, trolley table rotation mechanism is turned on and shutoff valves are opened in air duct. The operation to clean the electric motor in the chamber lasts 10-15 minutes.

The scope of mandatory work on the repair of the electric motor during the annual repair of cars includes: disassembly and assembly of the engine and repair of mechanical parts of the anchor, stator and suspension; repair of damaged windings; impregnation of windings; removal and check of bearings condition; lapping of brushes; drying and grinding of the manifold; dynamic anchor balancing; repair of brush holders; test of the electric machine on the bench and its painting. After disassembly of the machine, its individual units are defected on the basis of tolerance and wear standards, as a result of which the need for additional repair work is revealed.

During disassembly, bearing shields are usually removed, armature is removed from the stator, poles and pole windings are removed. Further disassembly of these main units is carried out if necessary based on the results of the defection. Before disassembling the engine, the casings are removed and the wires connected to them are disconnected from the terminal panel terminal terminals. Pressure devices of brush holders are also lifted and brushes are taken out.

After removing the bearing shields, the engine armature is removed. At the same time, the end of the shaft is wrapped with cardboard and a long pipe is put on it, with the help of which the rotor is carefully withdrawn, maintaining it on weight.

Ball bearings are removed from the shaft with the help of a regular type filmmaker, grabbing them by the inner race. If great effort is exerted, it is not recommended to install such a bearing again in the engine.

In case of failure of excitation windings or windings of additional poles, main and additional poles and pole tips are removed, after which their coils are disconnected and removed. When disassembling poles, they are pre-marked so that after assembly they are put in their place. All gaskets installed between poles and backbone are placed and preserved.

After disassembly, the electric motor parts are thoroughly cleaned. Dirt is removed from metal parts with a jet of compressed air, and from some places with rags wetted in warm water or gasoline. Special attention is paid to cleaning of electrical insulation parts. Fine dust, especially metal and coal, penetrating into the pores of insulation, reduces the electrical insulation qualities of the material. Cleaning the motor insulation from contaminants presents significant difficulties, since it is necessary to completely remove dirt without damaging the insulation. One of the simplest methods of cleaning the armature and windings is blowing electric machines with a jet of compressed air, followed by wiping the insulation with rags wetted in gasoline.

During periodic repairs, the brushes are replaced completely, installing brushes of brands recommended by the engine manufacturer. The brushes removed are inspected, paying special attention to the nature of their polished surfaces. Check gap size between bottom edge of a holder of the brush holder and a working surface of the collector. For the circulation pump motor, this clearance shall be 1-2 mm. If this gap exceeds the installed one, the brush holders move closer to the collector. By installing new brushes, they check the ease of moving them in the racks of the brush holders.

New brushes are lapped to the surface of the collector with skin. The final grinding of the brushes is carried out on the manifold of the engine itself. When checking the state of the cross-arm of the brush holders, they pay attention to the ease of moving the pressure fingers when lifting and lowering; at the same time, the fingers should not touch the side walls and cutouts of the brush holders. Finger insulation and insulation washers shall not be damaged. Check presence and reliability of locking bolts, pin attachment bolts and other fastening elements. Defective brush rack parts.

Removed bearings are washed in the bath with caustic soda and their wear is determined by checking the radial and axial gaps with the probe. If they do not meet the standards, they are replaced. Rollers, balls, cages and separators shall have no traces of overheating (colours of benevolence), cracks, fractures, ridges and worn rolling surfaces. Faulty bearings in the conditions of a car depot and car repair plants are not repaired, but replaced with new ones.

Bearing panels, bearing covers and engine housing are inspected before repair to detect cracks, wear of seats and holes and other defects. Large cracks in the shield spreading to the bearing seat do not plug, but replace the defective shield. Small cracks in steel parts are welded by electric arc welding. Before welding the board or frame to avoid deformation and change of seats, it is preheated to 700800C in a special furnace. It is also possible to brew cracks in a cold state with a copper electrode, which is wrapped with a strip of white tin and lubricated with liquid glass with OOM25 coating. The built-up copper is sprinkled with brown, and the resulting seam is forged. After the brewed shield or backbone cools, copper strains are removed from it.

After engine disassembly it is checked by magnetic flaw detector that there are no cracks at armature shaft. The shaft with cracks is not repaired, but replaced. The thread of the shaft for the nut or bolt in the end part is checked with a threaded caliber of the third accuracy class; worn thread is re-cut to the following size in accordance with GOST. Worn-out keyway is restored by laying metal on it by gas burner with further machining or cut again from diametrically opposite side of shaft. Worn mounting surfaces of the shaft (for pulley or clutch, bearings, etc.) are restored by surfacing or quenching with subsequent machining on a lathe.

If necessary, the shaft is ruled. Shafts with a bend of up to 0.1 mm by 1 m of its length, but not more than 0.2 mm for the entire length, it is not necessary to edit; shafts with a bend of 0.3% of their length can be edited in a cold state, with large bends, the shaft must be edited with heating.

Shafts with serious damage (fracture, large curvature of the crack) are replaced. Shaft is pressed out of anchor core by means of press. To fasten the armature and manifold parts removed from the shaft, I pass tightening studs through the armature vent and manifold housing.

Anchors cores should not have burrs, nicks, sheet shifting, breaking of extreme sheets, arson or burnout, as well as weakening of fit on the shaft. Small burrs, nicks and other damages that do not affect the integrity of the winding are sealed. In case of fusion of core with electric arc formed in case of armature damage, winding is removed and fused section is cut. The cut section shall not cover more than two grooves with gripping in separate places more than 15% of tooth thickness. The area vacated after cutting is cleaned from burrs and filled with asbestos filler prepared on BT95 varnish or other similar material. The repaired area is then coated with BT95 varnish.

If the fit of the core or pressure washers on the shaft is weakened, the extreme sheets are strongly stratified, there are splits or significant cracks in the pressure washers, the winding is removed from the core, the shaft is cut out, and the core is disassembled. Having examined the sheets, they replace defective ones (with cracks, broken teeth, etc.). Sheets having burns in one slot by no more than 15% of the tooth thickness can be installed in the core, but whole sheets are placed on both sides. The total number of damaged anchor sheets together with whole sheets installed between them should not exceed 40%. Pressure washers with significant splits are replaced; cracks in them are brewed on both sides. The core is assembled on a hydraulic press at a pressure of 1012 kgf/cm2 to obtain a monolithic core with the lowest magnetic resistance.

After assembly, it is checked whether the dimensions of the assembled core correspond to drawings; its beating must not be more permissible. Core repair is finished by cleaning burrs and protruding sheets in slots.

Engines received for repair of anchors by means of external inspection check state of insulation and strength of slot wedges, absence of damages and arson of section ends in places of their soldering to cockles of collector plates, quality of soldering, condition of bands. To eliminate faults between turns or sections, the collector is carefully cleaned from brush dust, excess tin and burrs. Disturbed insulation in the front part of the winding is restored by applying insulating gaskets made of electric cardboard or lakotkany on damaged places and coating them with insulating varnishes. If the cleaning of the collector does not give results and the visible front part of the winding is serviceable, the armature is transferred to the winding compartment to open the winding and eliminate damage. The winding is also opened when the ends of the sections in the cockles or splines of the cockles or the sections themselves are significantly fused.

Noticeably burnt edges of adjacent plates indicate possible break places in armature winding. Damage in accessible places (on the frontal parts) is eliminated by soldering wires, followed by isolation of the connection points with lakotkany and coating with insulating varnish. If the break point is in the slot, then the armature is transferred to the winding compartment, where the damaged section is unsealed from the collector and replaced.

Winding closure to the housing is most often caused by mechanical damage to its insulation. The reasons for such damage may be: the movement of wires in the slots under the influence of centrifugal forces during the rotation of the armature; shrouding weakening causing winding movement; excessive axial movement of the armature when starting the machine, as a result of which large inertial forces arise that shift the winding along its axis. As a result of the movements, the insulation, especially at the places where the sections leave the slots, is gradually masked. If the insulation of the armature winding is broken, the motor consumes a large current during starting, as a result of which the fuse installed in its circuit burns. Breakdown of insulation of upper sections is eliminated by using gaskets made of electric cardboard or lakotkany filled with insulating varnish. In other cases, the armature is transferred to the winding compartment, where it is partially or completely rewound.

The most common faults that cause damage to the collector are: burning from sparking brushes during machine overloads, manifold irregularities, weak brush pressure and vibration; uneven wear of the collector when using brushes made of harder material or their increased pressure; interlamar insulation protruding from working surface; closing the plates with brush dust, etc. Serviceable headers shall have strictly cylindrical shape and smooth polished surface without hairlines, scratches and burnt places.

The collector, on the surface of which there were found workings and irregularities with a depth of 0.2-0.5 mm, is ground with skin of grade 00, and then grade 000 until a mirror smooth surface is obtained. Under the conditions of the workshop, the collector is ground on a lathe or special combined machine used to groove and freeze the collectors.

If irregularities of more than 0.5 mm depth are detected on the surface of the collector, and also after repair associated with disassembly, the collector is leaked.

Eccentricity of manifold for engines must not exceed 0.08 mm. It is also unacceptable that separate plates protrude on the surface of the collector. To eliminate these defects, the manifold nut is carefully tightened, then heated to a temperature of 100-110 ° C and again tightened. Repair associated with manifold disassembly may require repeated tightening of the nut with alternating heating.

During operation, the copper plates of the collector are worn out much faster than the harder mycanite insulation gaskets. As the plates wear, insulation protrudes above the surface of the collector, causing vibration of the brushes and sparking. To prevent or eliminate this phenomenon, as well as during clogging of interlamel spaces with brushy dust, the collector is pressed, i.e. mycanite insulation between the plates is removed to a depth of 0.5-1 mm.

Collector plates and mycanite insulation with damage and significant wear are replaced by new ones.

The most common faults of the DC motor excitation windings are the breaking and rubbing of insulation, which cause faults to the housing and interturn faults. Depending on the nature of the faults, the defects found in the coil are eliminated or completely rewound.

After repair of the engine armature, its balancing is disrupted due to the uneven distribution of the impregnating varnish and tin, the asymmetric arrangement of the front parts of the winding. The imbalance causes vibration of the machine, accelerating wear of its bearings and mechanisms operating with it, weakening of the fastening elements, noise and additional energy losses. To eliminate the imbalance, balancing weights are added or part of the metal is removed at the appropriate positions of the rotor. Static and dynamic anchor balancing is performed to detect non-balance and to determine where to add or remove balancing weights.

To determine the quality of repair, the assembled engines are subjected to tests. The assembled engine shall be tested according to the following program:

• measurement of insulation resistance of all windings relative to each other and machine housing;

• measurement of winding resistance in cold state;

• test of electrical strength of windings insulation;

• idling test;

• insulation test between turns;

• Increased speed test;

• checking of nominal machine data;

• Short-term current overload test.

After testing, suitable engines are painted to protect them from corrosion and give a beautiful appearance.

Literature

1 E. A. Lisichkin. "Electric equipment of cars, its repair." Methodological guidelines for course design for students of the specialty "Wagons." Gomel: BIJT, 1992

2 A.E. Zorokhovich, A.Z. Libman "Electro and radio equipment of passenger cars." M.: "Transport," 1985

3 "Electric equipment of cars." Edited by Dr. Professor A.E.Zorokhovich. M.: "Transport," 1982

4 Tsyrlin M.I. "Basic requirements for the implementation of explanatory notes of course and diploma projects." - Gomel: BelGUT, 2001

5 Majorov V.N. Installation and repair of electric equipment of wagons. - M.: Transport, 1980