Measurements of g in the service of intelligence It's about not about military intelligence. There, knowledge of the acceleration of gravity is useless. We are talking about geological exploration, the purpose of which is to find deposits of minerals underground, without digging holes, without digging mines. There are several methods for very accurate

MEASUREMENTS AND THE TANK The probabilistic nature of quantum mechanics does not mean that we essentially know nothing. Moreover, often the opposite is true. We know quite a lot. For example, the magnetic moment of an electron is its integral characteristic,

EXTRA DIMENSIONS Neither supersymmetry nor technocolor give us a perfect solution to the hierarchy problem. Supersymmetric theories do not offer us experimentally consistent mechanisms of supersymmetry breaking, but create on the basis of technicolor force

To measure the losses and no-load current of the transformer, an open-circuit test is carried out. Measurement of losses x.x. allows you to check the condition of the magnetic circuit. If it is damaged (the insulation between the sheets is broken), the loss of x.x. increase. A sharp increase in current x.x. and losses x.x. are an indicator of the presence of a short circuit between the turns of one of the windings, local heating and damage to the windings.

Experience x.x. carried out after testing the electrical strength of the insulation. This is done in order to detect possible defects after this test.

In the x.x experiment, the rated voltage is applied to the low-voltage LV winding with the HV winding open.

ATTENTION! On the transformer, the ends of the cable must be removed from the HV terminals. To remove the characteristics x.x. it is necessary to assemble the circuit shown in Figure 3.4.

Figure 3.4 - Scheme for taking the characteristics of idling: 1 - induction regulator; 2 - set of instruments K-50 or K-505; 3 - tested transformer.

Applying voltage to the LV winding in the range from 0.5 to 1.1 U n, take measurements of the voltage, current and losses for each phase. U and measure with a kit K-505, Measuring kit K-505 measures the phase voltage, phase current and phase power, a U av, U sun, U with a PV voltmeter. Record the measurement data in Table 3.6.

Table 3.6 Idling experience

According to the measurement data, the calculated values ​​\u200b\u200bof U xx, P xx, I xx

, (3.3)

where U av, U sun, U sa- line voltages on the low side of the transformer.

, (3.4)

where I a, I c, I c– phase currents.

, (3.5)

where is the nominal value of the current of the winding to which the voltage is applied.

For three phase transformer

, (3.7)

where R st. - losses in steel;

R f- phase resistance of the winding to direct current.

Power P xx almost entirely spent on covering losses in the steel of the transformer core R st, since at x.x. losses in the windings are negligible compared to the losses in steel, then we can take P st » P xx.

Based on the measurements, it is necessary to construct the characteristics of the cold transformer I xx, P xx \u003d f (U xx). For newly commissioned transformers, the values P xx should not differ from factory data by more than 10% ( P xx =340 W for transformer TM-63/10).

7 Short circuit experience.

To measure losses and short circuit voltage, a short circuit test (short circuit) is carried out. In the experience of short circuit check the correct connection of the transformer windings and the condition of the contact connections.

Experience k.z. is carried out for the transformer at the nominal voltage regulation stage according to the scheme shown in Figure 3.5.

By smoothly raising the voltage, they set in the LV winding a current reduced in comparison with the rated current within 20% I n, i.e. I k \u003d 20 A.

ATTENTION! Measurements should be taken as soon as possible to avoid heating the windings.

Table 3.7 - Short circuit experience

According to the measurement data, the calculated values ​​\u200b\u200bare determined and the values ​​\u200b\u200bof the voltage and losses are brought to the actual short-circuit voltage. according to the formulas:

, (3.9)

where I A , I B , I C- phase currents during the experiment.

, (3.10)

where U AB , U BC , U AC- linear voltages on the high side of the transformer, measured during the experiment.

, (3.11)

where R a, R v, R s- phase powers measured during the short circuit test.

, (3.12)

where U K %- short-circuit voltage as a percentage of the nominal;

U N- the nominal value of the winding to which the voltage is applied.

I H- the nominal value of the current of the winding to which the voltage is applied.

Power supplied to the transformer in short circuit mode at rated voltage:

, (3.13)

According to the catalog data Р КН = 1290 W for transformer TM-63/10. Short-circuit losses of transformers consist of the sum of losses in the windings åI 2 R, (R is the active resistance of the phase of the transformer winding) and additional losses P ext. from the passage of stray magnetic fluxes through the walls of the tank, the metal parts of the fastening of the magnetic circuit and the conductors of the windings themselves, as well as losses in the magnetic circuit from magnetization. Losses from magnetization are neglected due to their small value (less than hundredths of a percent). Then R ext. = P to - åI 2 R .

The results of calculations should be reduced to a nominal winding temperature of 75 ° C (according to GOST II677-65) according to the formulas:

, (3.14)

where t meas- temperature at which the experiment was carried out, 0 С;

R n- rated power of the transformer (with cosj=1, R n\u003d cosj ×S \u003d 63 kW).

, W; (3.15)

On the basis of the measurements it is necessary to construct short circuit characteristics. I k , P k =f(U k).

8 When measuring the resistance of the transformer windings to direct current, the following characteristic defects may be revealed:

a) poor-quality soldering and poor contacts in the winding and in the connection of the inputs;

b) breakage of one or more parallel conductors.

The measurement of the active resistance of the windings in this case is carried out by the bridge method or by the method of an ammeter and a voltmeter. The measurement is made on all branches and on all phases. Measurement data should be entered in table 3.8.

Table 3.8 - Resistance of DC transformer windings

After all measurements, a summary table 3.9 of the test results is compiled and a conclusion is given on the technical condition of the transformer and its suitability for operation.

Table 3.9 - Summary table of test results reduced to normal conditions (75 ° C)

Note:

Conclusion:

Report content. In the report, give the purpose of the work, write down the passport data of the transformer, give a brief description of the control tests of transformers, draw diagrams for testing and measurements, present tables with experimental and calculated data and analyze them, draw the characteristics of x.x., short circuit characteristics, draw a conclusion about the suitability of the transformer for operation.

Test questions.

1 What is the purpose of grounding the transformer windings before starting the measurement of insulation resistance?

2 What are the main characteristics of the insulation of the transformer.

3 What are the consequences of reducing the insulation resistance of the transformer winding?

4 How does the absorption coefficient change depending on the degree of wetting of the insulation and what explains this?

5 How to measure the insulation resistance of the windings of power two-winding transformers?

6 What is the purpose of measuring the transformation ratio of a transformer?

7 What methods of checking the connection group of transformer windings are used in practice? Why is the two voltmeter method the most common?

8 When measuring the transformation ratio, the following data were obtained: K av \u003d 25, K sun \u003d 25, K ac \u003d 30. Determine the malfunction in the transformer.

9 How and for what purpose is the electric strength test of the main insulation of the transformer windings carried out?

10 What is the purpose of measuring the resistance of the DC windings of a transformer and by what methods?

11 What is the purpose of the no-load test and why is it carried out after the dielectric strength test?

12 For what purpose and how is a short circuit test carried out?

13 What parameters of the transformer are determined from the experiments of idling and short circuit?

LAB #4

DEFECT OF ASYNCHRONOUS ELECTRIC MOTORS

WITH SHORT CIRCUIT AND PHASE ROTOR

IN REPAIR

The purpose of the work: to study the main malfunctions of asynchronous electric motors and their causes, to master the technique for detecting malfunctions of asynchronous electric motors.

Work program.

1 Carry out an external inspection of the electric motor and record the passport data.

2 Carry out fault detection of the electric motor before disassembly:

Measure the resistance of the windings to direct current;

Measure the insulation resistance of the stator windings relative to the housing and relative to each other;

Check the rotation of the rotor and the absence of visible damage preventing further tests and inspections.

3 Dismantle the motor.

4 Carry out fault detection of the electric motor in disassembled form:

Check the condition of mechanical parts and components of the electric motor;

Measure the air gap between the stator and the rotor;

Check the absence of short-circuited turns (turn circuit), open circuit in the winding;

Determine the location of damage to the stator windings;

Determine, record winding data and draw a winding diagram;

Check the condition of the active steel of the stator;

Check the squirrel cage of the rotor for breaks in the rods and rings.

If there is an electric motor with a phase rotor, then the flaw detection of the rotor winding is carried out similarly to the flaw detection of the stator winding. Additionally, the insulation strength of slip rings is tested and the condition of the active steel of the rotor is checked;

All detected malfunctions of mechanical parts, rotor and stator windings, electric motor data should be entered in the troubleshooting list or repair schedule.

1 Asynchronous electric motors received for repair are carefully examined, and, if necessary, tested and disassembled in order to fully identify the causes, nature and extent of damage. Inspection of the electric motor, familiarization with the volume and nature of previous repairs and operational logs, as well as testing, allow us to assess the condition of all assembly units and parts of the electric motor and determine the scope and timing of repairs, draw up technical documentation for repairs.

Electric motors are most often damaged due to unacceptably long periods of operation without repair, poor maintenance or violation of the operation for which they are designed.

Damage can be mechanical or electrical.

to mechanical damage include: smelting of babbitt in plain bearings, destruction of a separator, ring, ball or roller in rolling bearings; deformation or breakage of the rotor shaft; loosening of the fastening of the stator core to the frame, rupture or slipping of the wire bandages of the rotors; weakening of the pressing of the rotor core and others.

electrical damage are: breakage of conductors in the winding, short circuit between turns of the winding, broken contacts and destruction of joints made by soldering or welding, breakdown of insulation on the housing, unacceptable decrease in insulation resistance due to its aging, destruction or moisture, etc.

A brief list of the most common faults and possible causes of their occurrence in asynchronous machines is given in Table 4.1.

Malfunctions and damage to electric motors are not always possible to detect by external inspection, since some of them (turn short circuits in the stator windings, insulation breakdown on the housing, soldering failure in the windings, etc.) are hidden and can only be determined after appropriate tests and measurements.

Table 4.1 - Malfunctions of asynchronous machines and possible causes of their occurrence

2 Fault detection of the electric motor before disassembly.

The number of pre-repair operations for identifying faults in electric motors includes: measuring the insulation resistance of the windings, checking the integrity of the windings, testing the electrical strength of the insulation, checking the bearings at idle, the magnitude of the axial run-up of the rotor, determining the condition of fasteners, the absence of damage (cracks, chips) in individual motor parts:

a) the measurement of the resistance of the DC windings is carried out in order to check the absence of breaks in the winding, for example, due to a violation of the integrity of the joints as a result of poor-quality soldering. Resistance measurement is carried out using a DC bridge UMV, R353 and others with an accuracy class of at least 0.5. The measured winding resistances should not differ from each other by more than 2%;

b) measurement of the insulation resistance of the motor windings is carried out according to the methodology set out in the general instructions (p. 8-9) .

c) the rotor of the electric motor is turned to check its free rotation and the presence of run-out. For small machines, this operation is carried out manually. Such a check is obligatory before the first start-up of the machine or after its long parking in conditions where foreign objects could get into the machine.

3 Disassembly of the electric motor is carried out using locksmith tools.

4. Detection of the disassembled electric motor is carried out in the following order:

4.1 Determine the condition of mechanical parts and individual components by external inspection.

4.2 Check the air gap with a set of feelers at least at four points by turning the rotor clockwise by 90°. The arithmetic mean of the measurement results is compared with the allowable values ​​(table 4.2). The deviation should not exceed ±10%.

Table 4.2 - Normal values ​​of air gaps

induction motors

4.3 Determine the damage to the insulation in the motor, which leads to short circuits.

Depending on the type of insulation damage, the following short circuits are possible:

Between the turns of one coil in the groove or frontal parts (turn circuit) in case of damage to the interturn insulation;

Between coils or coil groups of the same phase in case of damage to the intersectional insulation;

Between coils of different phases in case of damage to the interphase insulation;

Short circuit to the body in case of damage to the slot insulation.

By passing an alternating current of low voltage through the individual phases of the winding, it is possible to determine the location of the turn circuit. Short-circuited turns, when the phase is turned on under voltage, are, as it were, the secondary winding of an autotransformer, short-circuited. Large currents flow through short-circuited turns, which heat the frontal part of the winding. By local heating, the place of the turn circuit is determined.

A closed loop is easily determined using a horseshoe electromagnet.

Figure 4.1 - Finding a closed coil using an electromagnet and a steel plate, where it is indicated: a) there is no coil closure; b) there is a closure of the turns; 1 - winding conductor; 2 – electromagnet; 3 - steel plate; Ф - magnetic flux of the magnet; Ф pr - magnetic flux of a short-circuited conductor with current.

To find short-circuited turns in the winding sections, the electromagnet is installed parallel to the stator slots. After the electromagnet winding is connected to the AC electrical network (220 V at a frequency of 50 Hz), a current will flow through the winding, which will create a magnetic flux Ф, closing through the electromagnet core and part of the magnetic circuit of the stator of the electric motor. This variable magnetic flux will induce an emf in the conductors covered by the circuit.

In the absence of turn short circuits (Figure 4.1-a) in the winding, the EMF does not cause the appearance of current (there is no closed circuit for it). In the presence of short-circuited turns, the EMF will cause a current to appear in them, and a significant value due to the low resistance of the circuit. The current will create a magnetic flux Ф pr around short-circuited turns (Figure 4.1-b). The latter are easily detected by a steel plate that is attracted to the stator teeth above this slot. In production, a device of the EL-1 type is also widely used to determine turn short circuits.

Short circuit to the body(if the megaohmmeter shows zero) can be determined using a millivoltmeter. This method is associated with alternately desoldering the winding into separate coils and checking each of them. Voltage is supplied to both ends of the damaged phase from one battery clamp with a voltage of up to 2.5 V, and the second clamp is connected to the case. When measuring the voltage on each coil, a change in the polarity of the reading of the device indicates the passage of the phase closure point to the case. This method, due to the laboriousness of the work, is not always acceptable, especially with a large number of coils.

It is better to use the magnetic method (2), which is based on the following. From a low voltage source (U to 36 V), a single-phase alternating current is supplied to the end (or to the beginning) of the faulty phase and through a rheostat and an ammeter to the motor housing. Since the current is alternating, an alternating electromagnetic field is formed around the conductors with this current. Therefore, the grooves with a conductor through which current flows are easily determined using a thin steel plate (probe), which slightly rattles. The latter makes it possible to identify the sections through which the current flows from the end of the phase winding to the place of the short circuit to the housing. To check and clarify the found location of the winding short circuit, the current is now supplied to the beginning of the faulty phase. With a single circuit of the winding, the found places of short circuits in the first and second cases should converge.

The faulty coil found by the magnetic method is disconnected from the rest of the winding and the correctness of the established location of the short circuit to the case is checked with a megohmmeter.

The same method can be applied to find the fault location between phases.

In this case, the voltage is first applied to one end of the closed phases, and then to the other. This makes it possible to identify closed sections.

Internal breakage of one of the phases.

If the winding has six leads, then the broken phase is determined using a tester or megohmmeter.

If the winding has only three leads, then the broken phase is determined by measuring currents or resistances.

When the phases are connected in a star, (figure 4.2) the current of the broken phase is zero, and the resistance measured relative to the output of the broken phase is equal to “infinity”.

Figure 4.2- Determination of internal phase loss when connecting phases to a star.

When the phases are connected in a triangle, the currents suitable for the broken phase (Figure 4.3) will be equal and less than the currents in the phase (unbroken), and the resistance measured on the broken phase (C1-C3) will be twice as large as the other phases (C1-C2, C2-C3).

Figure 4.3 - Determination of internal phase failure when connecting phases in a delta.

After determining the broken phase, the place of the break is determined with

Figure 4.4 - Determining the location of the break in the broken phase:

a) using a voltmeter; b) using a control lamp.

Measure the voltage at the ends of each coil or coil group. At the moment of reading the voltmeter, a broken coil is determined (Figure 4.4a). Touching the probe from the lamp to the beginning and end of each coil, going from the potential end of the network, the reading of the lamp will show a break (the lamp is off, it means a break, if on the other hand, then vice versa).

For one of the asynchronous motors under consideration (with a faulty coil), determine and record the winding data and draw a winding diagram.

Inspect the package of active steel of the stator. The steel package should not have displacement, dents, weakening of the pressing of iron sheets, fluffy teeth, burnout.

The integrity of the squirrel-cage rotor bars is determined by the alternating current electromagnet method. When testing, the rotor is mounted on an electromagnet connected to the AC mains (Figure 4.5).

A steel plate covering a groove with a whole rod will be attracted and rattle. If the rod is broken, the plate is not attracted or is attracted very weakly. The rupture site is found using a sheet of paper with steel filings sprinkled on it.

Detected malfunctions of mechanical parts, stator and rotor windings, data of electric motors submitted for fault detection should be entered in the fault list or repair flow chart.

TECHNOLOGICAL CARD No.

Customer _________________________

I Specification

II Winding data

Note_____________________________________________________

III Mechanical

IV Winding control

Notes_________________________________________________

V Bench tests

Head of Quality Control Department ____________________________________________

Report content. The report must include: the purpose of the work, the main schemes and data on identifying faults in electric motors submitted for fault detection, sketches of missing and requiring parts, a completed repair flow chart, a detailed diagram of the stator winding of a motor whose winding needs to be replaced, a conclusion on the results of fault detection of electric motors .

Test questions.

1 What is the purpose of fault detection of an electric motor before repair?

2 In what sequence and how is the fault detection of the electric motor carried out before disassembly?

3 What are the consequences of reducing the insulation resistance of the stator winding and what should it be for motors with U< 500 В?

4 How to detect a turn short circuit in the stator winding when the motor is running?

5 In what sequence and how is the fault detection of the electric motor carried out after disassembly?

6 What are the main faults of the stator winding and how to identify them?

7 When an electric motor with a squirrel-cage rotor is connected to the network, an increased heating of the active steel of the stator is observed in the idle mode. What is the problem with the motor?

8 When the motor is running, the stator winding gets very hot. The magnitude of the current in the phases is not the same. The electric motor hums a lot and develops reduced torque. What could be wrong with the engine?

9 The electric motor runs poorly and hums a lot. The current value in all phases is different and exceeds the nominal value when the motor is idling. What is the problem with the electric motor?

10 A squirrel-cage motor does not reach its normal speed, but "stuck" and starts to work steadily at a low speed, which is much less than the nominal one. What is the problem with the electric motor?

LAB #5

Asynchronous motor test

with phase rotor after repair

The purpose of the work: to master the method of testing an electric motor with a phase rotor after repair.

Work program:

1 Inspect the electric motor, check the tightening of the fixing bolts, the rotation of the rotor, write down the passport data.

2 Measure the insulation resistance of the stator windings relative to the housing and relative to each other and the insulation resistance of the rotor winding relative to the housing.

3 Mark the output ends for direct and alternating current.

4 Measure the resistance of the stator and rotor windings to direct current.

5 Check the transformation ratio of the asynchronous motor with a phase rotor.

6 Carry out an idle test.

7 Carry out a turn-to-turn insulation test.

8 Conduct a short circuit test.

9 Carry out a dielectric strength test.

1 During an external examination of the electric motor, the tightening of the fixing bolts and the rotation of the rotor are checked. When rotating the rotor by hand, there should be no jamming and play in the bearings. Passport data of the electric motor are recorded.

2 Measuring the insulation resistance of the motor windings is carried out according to the methodology set out in the general instructions (p. 8-9) . . Record the measurement data in Table 5.1.

Table 5.1 - Insulation resistance of the motor windings

3 GOST 183-66 provides for the designations of the conclusions of the windings of electrical machines of three-phase alternating current (table 5.2).

Table 5.2 - Designation of the conclusions of the windings of electrical machines of three-phase alternating current

Usually, the conclusions of all phases of the stator winding are connected to the clamps, as indicated in Figure 5.1 a. In some machines, the stator windings are tightly connected into a star and only four outputs are displayed on the terminal board: phases C1, C2, C3 and zero point 0.

If there is no marking of the stator winding leads, then paired phase leads are first found using a test lamp; one of the phase leads is taken as the beginning of the winding and connected to the plus of a 4-6 V DC source; one of the outputs of the control lamp is connected to the minus of the source, and the second output of the lamp is used to find the end of the phase winding. Or a megohmmeter is connected with the "Line" clamp of the megohmmeter to the intended beginning of the phase of the stator winding and the end of the phase is found with a wire connected to the "Earth" terminal of the megohmmeter. In this case, the megaohmmeter will show zero. After that, a label with the marking (C1, C2 ...) is put on each phase output.

Marking of output ends is carried out on direct or alternating current. With direct current, two options are most common (Figure 5.2)

The terminal marking is carried out using a battery ( U= 4 - 6 V) and a millivoltmeter (M104).

In the first option a) we take С1, С2, СЗ for the beginnings of phases 1,2,3, and С4, С5, С6 - for the ends of these phases. If the beginning of phase 1 is connected to the "plus" of the battery, and the end to the "minus" (Fig. 5.2, a) , then at the moment the current is turned on in the windings of other phases (2 and 3), an EMF will be induced with a minus polarity at the beginnings and a plus at the ends of the phases. The millivoltmeter is connected to phase 2, and then to phase 3. If the arrow of the device deviates to the right in both cases, then all ends of the windings are marked correctly.

Figure 5.2 - Schemes for checking the marking of the stator terminals using a direct current source: a) - the first option; b) and c) - the second option; H and K - respectively, the beginning and end of the windings 1,2,3.

In the second option b) and c), two phases are connected in series (in pairs) to each other and the pulse is switched on to the battery. A millivoltmeter is connected to the third phase. If the first two phases are connected by terminals of the same name (Figure 5.2.b.), the millivoltmeter will not show anything. When connecting the phases with opposite clamps (Figure 5.2. "c"), at the moment the battery is turned on, the arrow of the millivoltmeter will deviate to the right.

With alternating current and with the six ends of the phases removed, the induction method of marking the terminals is the most common (Figure 5.3).

Figure 5.3 - Scheme of the induction method for marking stator terminals using an alternating current source:

H and K - respectively, the beginning and end of the windings 1,2,3;

T V - adjusting transformer.

Installation of crowns is a method of correcting the dentition. However, there are situations when it is necessary to correct not only the teeth, but also the gums. This is due to both aesthetic and technical reasons: sometimes, due to an incorrectly shaped gum, the doctor cannot securely fix the prosthesis. How the gums are cut under the crown - read below.

The operation can be assigned in the following cases:

1. "Short teeth" due to too wide band of gum tissue.
2. An uneven edge that looks unaesthetic.
3. The gap between the gum and the tooth (pocket) is too large.
4. Inflammatory processes (, gingivitis), which serve as an obstacle to fixing the crown.
5. Damage to the gum tissue with the risk of spreading it to neighboring areas.

There are a number of indications for the operation.

In these cases, tissues must be removed not only for aesthetic reasons, but also due to the fact that the gap between the teeth and gums is a place where bacteria accumulate that can lead to the development of inflammatory processes.

The operation is not carried out if there is contraindications, which include:

• decompensated diabetes mellitus;
• blood diseases;
• cardiovascular diseases in the stage of decompensation;
• infectious diseases in the acute stage;
• immune pathologies.

In addition, the operation is not indicated if the inflammation has already affected the bone tissue.

How is pruning done?

The procedure can be divided into several stages:

1. Professional cleaning. The gap between the crown and the gum is a place of accumulation of bacteria, the formation of tartar and plaque. Before proceeding with the operation, you need to get rid of them.
2. Introduction of local anesthesia.
3. Removal of tissues.
4. Surface treatment with an antiseptic, applying a bandage with a special antibacterial solution.

The operation itself is carried out under one of the following methods:

• Simple. The doctor measures the depth of the pockets and marks the level along the entire gum line. An incision is then made and the gum strip is excised.
• Partial. This method is similar to the previous one, the only difference is that not all tissue is excised, but only part of it in a small area.
• Radical, in which not only gum tissue is removed, but also granular, and also, in some cases, altered bone. Recently, this technique has been rarely used.

Both a scalpel and a laser can be used as an instrument. Laser operations are less traumatic due to the fact that the beam provides not only tissue removal, but also coagulation. In addition, such procedures are contactless, and therefore complete sterility is ensured.

Cutting at implantation

Complications after the procedure are rare.

During implantation, gum trimming can be performed on different stages procedures:

1. In preparation for it. Such an operation is performed, as a rule, if the gum tissue is necrotic due to inflammatory processes and cannot be restored. It can take 2-3 weeks from this operation to the installation of the implant.
2. During implantation, simultaneously with manipulations to increase the volume of bone tissue.
3. After implantation, if the gum line is incorrect.

In all these cases, pruning plays not only an aesthetic role. It is very important to protect the implant from infection and prevent the development of peri-implantitis, which can lead to the destruction of the entire structure and.

Care after surgery

The recovery period takes, as a rule, no more than a week. Complications in this case develop very rarely, and usually only if the surgeon was not made aware of the presence of contraindications or did not take them into account. Another reason for the development of complications is the patient's failure to follow the rules of postoperative care, which include:

• Rinse with antiseptic solutions prescribed by the doctor.
• Compliance with a diet with the rejection of solid, hard, hot, spicy foods.
• Quit smoking and alcohol.
• Limitation of chewing loads.
• Observance of accuracy when brushing teeth, avoiding pressure and other mechanical influences.

Since the installation of the crown can be traumatic due to the grinding of the tooth, it is carried out after a few days. Regardless of what is required - under a solid crown or any other, the doctor starts this stage of prosthetics only after the complete healing of the operated gum.

Sources:

1. Robustova T.G. Surgical dentistry. Moscow, 1996.
2. Kopeikin V.N. Orthopedic dentistry. Moscow, 2001.

Experience

noun, m., use often

Morphology: (no) what? experience, what? experience, (see) what? experience, how? experience, about what? about experience; pl. what? experiments, (no) what? experiments, what? experiences, (see) what? experiments, how? experiences, about what? about experiences

1. Experience- this is the knowledge, skills and abilities that a person or any community of people has acquired in the process of life, practical activity in a particular area.

Experience. | Positive, negative experience. | Acquire and share experience. | To share experience. | Learn, use someone else's experience. | Experience exchange. | Rely on someone else's experience. | Learn from the experience of elders. | Convince yourself of something on your own experience. | Adolescents do not yet have the experience of independent living. | Behind the director's shoulders is a solid experience of work at his own enterprise.

2. experience you call the knowledge of life based on what you have lived and experienced.

Huge personal experience. | Living experience. | Experienced people. | Taught by bitter experience.

3. In philosophy experience called the totality of sensory perceptions that a person acquires in the process of interaction with the outside world and which constitute the source and basis of his knowledge about this world.

Experience is the source of all knowledge.

4. In science experience called the reproduction of a phenomenon or the observation of a new phenomenon under certain conditions with the aim of studying and researching them.

Conduct, put, do the experience. | An original, bold, interesting experience. | Good, bad experience. | Laboratory experiments. | Physical, chemical, livestock experiments. | What are the results of the experience? | Experiments on animals and humans. | The first successful experiments on correcting vision with a laser were carried out in the early 1980s.

Experiment

5. Experience- this is your attempt to do something, the trial implementation of something.

Literary, poetic experiments. | Early experiences of a young playwright. | Experiences of the painter in the field of book graphics.

experienced adj.

Explanatory dictionary of the Russian language Dmitriev. D.V. Dmitriev. 2003 .

See what "experience" is in other dictionaries:

experience- Experience and... Russian spelling dictionary

Based on the practice of the senses. empirical knowledge of reality; in a broad sense, the unity of skills and knowledge. In the history of philosophy, the views of empiricism and sensationalism have become widespread, according to which feelings. the data is... Philosophical Encyclopedia

The source of our wisdom is our experience. The source of our experience is our stupidity. Sacha Guitry Experience is the totality of our disappointments. Paul Auger Experience is lost illusions, not wisdom gained. Joseph Roux Teaching is the study of rules; learning experience... Consolidated encyclopedia of aphorisms

EXPERIENCE, experience, husband. 1. pl. rare.. The totality of practically learned knowledge, skills and abilities. “In order to lead correctly, it is necessary to supplement the experience of leaders with the experience of the party masses, the wholesale of the working class, the experience of the working people, the experience ... ... Explanatory Dictionary of Ushakov

Try, experiment. Attempt at writing. First debut. See the test .. taught by experience, wise by experience ... . Dictionary of Russian synonyms and expressions similar in meaning. under. ed. N. Abramova, M .: Russian dictionaries, 1999. experience, test, test, ... ... Synonym dictionary

Experience- Experience ♦ Expérience A way of comprehending reality; everything that comes to us from the outside (external experience) and even from within (internal experience), provided that as a result we learn something new. Opposes reason, but at the same time ... ... Philosophical Dictionary of Sponville

Empirical knowledge of reality; unity of knowledge and skills. Experience acts as a result of the interaction of man and the world and is transmitted from generation to generation ... Big Encyclopedic Dictionary

experience- EXPERIENCE, EXPERIMENTAL experiment, trial, experimental ... Dictionary-thesaurus of synonyms of Russian speech

experience- a way of knowing reality, based on its direct, sensual practical development. O. serves as an important source of information both about the external objective world and about the mental life of the subject. In psychology, the concept of O. ... ... Great Psychological Encyclopedia

EXPERIENCE, sensually empirical knowledge of reality; unity of knowledge and skills ... Modern Encyclopedia

L) a philosophical category that fixes the integrity and universality of human activity as a unity of knowledge, skill, feeling, will. Characterizes the mechanism of social, historical, cultural inheritance; 2) epistemological category ... History of Philosophy: Encyclopedia

Books

• Experience of the history of Eurasia. Links of Russian culture, G. V. Vernadsky. For the first time in Russia, two fundamental books by the greatest historian of the Russian diaspora, GV Vernadsky, are published: "The Experience of the History of Eurasia" and "Links of Russian Culture". They show that in…

Sigmoidoscopy is an endoscopic type of examination with which you can examine the rectum, lower sigmoid. The examination is carried out using a device - a sigmoidoscope, which is inserted into the anus, especially when patients have blood in the stool.

Indications for examination

1. Isolation of blood from the anus;

2. Chronic constipation or diarrhea;

3. Frequent pain in the anus, discharge of pus and mucus;

4. If you suspect oncological diseases;

5. With chronic hemorrhoids.

Of course, there are no contraindications to sigmoidoscopy. But it must be taken into account that the procedure is difficult to tolerate: if patients have cardiovascular diseases, with anatomical narrowing of the anus and rectum, in the presence of inflammation in the anus.

Required preparation

The main condition for an effective examination is the cleansing of the colon. Three days before the procedure, it is necessary to exclude vegetables, fruits, dairy products from the diet, limit the consumption of bread. On the eve of the study, you can only take tea.

Preparation with the laxative drug Fortrans

1. We prepare the solution according to the instructions -1 packet of powder must be dissolved with 1 liter of warm water. Calculation of the drug: for 20 kg of the patient's weight - 1 package (but more than 4 packages cannot be taken);

2. Beginning of acceptance of Fortrans no later than 18-00;

3. Take the prepared solution gradually (not in one gulp). 1 glass - for 10 minutes, then the next;

4. Take the required dose in two doses, with an interval of 2 hours;

5. Finish the reception no later than 3 hours before the procedure;

6. The drug is contraindicated in children;

7. Do not use for the purpose of losing weight, because. possible dehydration.

How is RRS performed?

The examination is carried out on the couch, the patient is in the knee-elbow position. First, a digital examination is performed, and then the doctor inserts the tube of the proctoscope lubricated with vaseline to the required depth. A rectoscope is a metal tube 2 cm in diameter, 30 cm long. During the examination, the doctor examines the mucous membrane, can detect the presence of neoplasms, polyps, hemorrhoids, cracks. If necessary, he takes material for histological examination.

In addition, it is necessary to psychologically and morally tune in to the manipulation (unpleasant, but necessary). Of course, during sigmoidoscopy, there is a feeling of discomfort, but the procedure is painless and anesthesia is not used (only in extreme cases - with cracks and injuries of the anus).