According to the rules technical operation in the system of scheduled preventive repairs of electrical equipment (PPREO), two types of repairs are provided: current and capital.
Maintenance
It is carried out at intervals (set by the chief power engineer) for all electric motors in operation. In a typical scope of work for current repair are included the following types work: external inspection of the electric motor, flushing and relubrication of bearings and, if necessary, replacement of rolling bearings, inspection and repair of fans and cleaning ventilation devices and channels, cleaning and blowing compressed air windings, slip rings, collectors, brush apparatus, checking the state of fastening of the front windings, restoring the varnish cover of these windings, grinding contact rings and collectors, adjusting the brush apparatus, wiping and replacing brushes, driving the collectors, checking and tightening all threaded fasteners, checking protective earth, carrying out preventive tests.
Overhaul
It is carried out in the conditions of an electrical repair shop (ERTS) or a specialized repair enterprise (SRP). In volume overhaul includes the work provided for by the current repair. It also includes the following types of work: complete disassembly of the electric motor, checking of all components and parts and their fault detection, repair of frames and end shields, rotor and stator magnetic circuits, shafts, fans, rotors, collectors, elimination of local defects in the insulation of windings and connections, carrying out post-repair testing.
The frequency of major repairs of electric motors is not established by the Rules for technical operation. It is determined by the person responsible for the electrical facilities of the enterprise based on estimates of the total duration of the operation of electric motors and local conditions for their operation.
After transportation, for the installation of electric motors on foundations, the following additional work: alignment of the position of the electric motor, alignment and alignment or new electric motor and unit, fastening, grouting the bases. Partial replacement of windings is advisable in case of damage to several single-layer coils or rod windings (partial replacement of double-layer stator windings is not advisable, since the insulation of serviceable coils is damaged).
Wires removed from damaged electric motors during the repair period are reused. In this case, it is necessary to restore the electrical and mechanical parameters of the windings to their original values. For wire cleaning, see old insulation annealing in furnaces is used, and the mechanical separation of insulation residues from the wire is carried out by drawing through wooden or textolite clips. After straightening, the wires are wrapped with new insulation on the machines.
When repairing stator windings from rigid coils copper wires rectangular section reused Insulation is repaired by overlapping with tape overlapping ½ the width of the tape. The replacement of collectors is carried out only in case of significant damage (five or more collector plates) with breakdown and burnout of the insulation.
In addition, the collectors must be replaced as a whole, if the margin of the collector plates in height does not ensure their natural wear without reducing this size below the allowable limit in the time before the next overhaul.
Existing electrical equipment.
The scope of work on maintenance and repair is carried out according to the standard scope of work given in the PPRES system for two to three main types of electrical equipment available on the farm. For example, let's take electric motors, start-up equipment and power and lighting wiring, switchgear and lighting panels.
Scope of work on maintenance and current repair of asynchronous electric motors with a squirrel-cage and phase rotor.
Maintenance and current repairs of electric motors are carried out for all electrical machines in operation. electrical machines are carried out at the place of their installation, without dismantling and disassembly. Current repairs of electrical machines can be carried out at the place of their installation or at a maintenance point, in a workshop, etc.
– . Clean the housing from dust and dirt, check the grounding, tighten the engine mounting bolts to the foundation or the working machine. Check the degree of heating and the level of vibration of the housing, check the alignment of the motor with the working machine, the reliability of fastening the pulley or sprocket on the motor shaft, check the reliability of the contact connections, make sure that there are no abnormal noises when the motor is running, check the condition of the slip rings of the brush mechanism for motors with a phase rotor, measure the insulation resistance of the winding. If minor defects are found, they must be eliminated.
– current. Clean the motor housing from dust and dirt, disconnect the motor from the power wires and grounding. For motors with a phase rotor, disconnect the wires from the starting rheostat. Remove the engine from the installation site and disassemble it. Clean the windings, measure the insulation resistance, dry the windings if necessary. Check the condition of the slip rings, clean and grind them if necessary. Adjust the brush mechanism, if necessary, replace the brushes. Wash the bearings, check them technical condition and replace if necessary. Repair or replace damaged winding lead wires and terminal box terminal board. Assemble the motor, lubricate the bearings, test the motor at idle. Paint the engine if necessary. Install the engine on workplace, adjust its alignment with the working machine and test it under load.
Scope of work on maintenance and current repair of start-up protection equipment.
Maintenance of start-up devices is carried out at the place of their installation. The current repair of devices, depending on the nature and degree of damage, can be carried out at the place of their use, in a mobile or stationary workshop.
– Maintenance . Remove voltage from the device being serviced, clean it of dust, check the reliability of fastening, free movement of moving parts, check the degree of tightening of screw connections and tighten loose ones. Inspect the device and make sure that there are no damages in it, remove the arc chutes, inspect, check the tightness of their fit, the condition of the springs, the simultaneity of switching on, if necessary, adjust the simultaneity of switching on the contacts and clean them from carbon deposits, make sure that there are no signs of overheating of the contacts of screw connections and fuses. In control panels, check the serviceability of signal lamps and their fittings, locking devices and door seals. After completing these works, apply voltage and check the operation of the equipment.
– Maintenance. Dismantle the device, check and tighten all fasteners, partially disassemble the device and clean it from dust and dirt, clean it from melting and soot, replace faulty parts, clean and paint the shell, assemble the device, adjust its components. Adjust thermal relays after repair. Check the assembled device for operability, install it in its place and test it in operation.
Scope of work on maintenance and current repair of power and lighting wiring, switchgear and lighting shields.
Power wiring :
– Maintenance . Clean the wiring from dust and dirt. Check the condition of the wiring fastening, eliminate sagging if necessary, check the strength of the fastening of the mechanical protection of the wiring, check the compliance of the cross-sectional area of the wiring with the actual current load, the condition of the marking. Check the state of grounding of metal protective structures.
– Maintenance. Perform maintenance operations. Replace individual defective sections of wiring, couplings, funnels, etc. Check the insulation resistance with a megger, paint the brackets and other fastening metal structures.
Lighting wiring :
– Maintenance . Clean the wiring from dust and dirt. Check the condition of the wiring fastening, fix if necessary separate sections. Check the condition of switches and sockets, lighting boxes, eliminate any defects. Check the condition of the wire connections in the junction boxes. Reinforce wiring with damaged insulation by applying several layers of electrical tape. Check the state of grounding of metal protective structures.
– Maintenance. Perform maintenance operations. Replace individual defective sections of electrical wiring, faulty switches and sockets. Check the insulation resistance of the wiring with a megger.
Power builds:
– Maintenance . Clean the power assembly from dust and dirt. Check and, if necessary, tighten at the junction of the busbars with each other, as well as at the points of connection of cables and wires. Check the condition of the contacts of knife switches, fuses, contactors, etc. Check that the currents of the fusible links correspond to the rated currents. Check the grounding condition of the assembly case.
– Maintenance. Perform maintenance operations. Replace individual defective busbars, switches, contactors, etc. Check the condition of the insulation of current-carrying parts. Replace defective insulators or panels. Repair locking devices and assembly housing. Run painting work, restore warning labels on assemblies.
Lighting shields :
– Maintenance . Clean the shield from dust and dirt. Check the condition of the contacts between the shield busbars, cables and wires. Check the condition of the switching devices of the fuses, the compliance of the currents of their fuse links with the calculated values, the condition of the grounding of the shield.
- Maintenance . Perform maintenance operations. Check the condition of the insulating parts of the shield, replace defective parts. Replace burnt tires, switching devices and fuses. Paint the shield cover, restore the warning labels.
5.4. Consumption of materials for maintenance and repair and spare parts of electrical equipment for a year of operation.
The consumption of materials and spare parts for maintenance and repair for the entire economy as a whole, but only for the main equipment - for engines, magnetic starters, thermal relays, lighting and irradiation equipment, we will calculate according to the norms of PPREsh for the year of operation.
Materials and spare parts for maintenance and repair of electrical equipment allow you to determine the stock of materials and the number of spare parts for the year of operation.
Consumption of materials for maintenance of electric motors per year of operation.
Table 5.4.2
|
Consumable Material |
Material characteristic |
, kg. per unit |
For the owner as a whole, |
|
|
Brand, standard number |
Assortment |
|||
| GOST 1012–72 | ||||
|
Kerosene lighting |
KO–30, GOST 4753–68 | |||
| CIATIM, GOST 8773–73 | ||||
|
Fasteners |
||||
| 1 POA, GOST 2162–78 | ||||
|
Cleaning rags |
629, GOST 5354–79 | |||
| 1E, GOST 5009–82 | ||||
1E, GOST 6456–82
760´30LOG15А80–N
620´50P215A40…3–N
The reference book shows the consumption rates for one current repair of an asynchronous electric motor with an average power of 5 kW. The need for materials for current repairs of electric motors for the year of operation is set depending on the frequency of current repairs of electric motors in the economy. Then, if the average power of electric motors is 5 kW, the given norms should be multiplied by the number of current repairs. If the average power differs from 5 kW, when determining the need for materials for current repairs, correction factors should be used:
with an average power of up to 2 kW, the coefficient is 0.5, up to 3 kW - 0.6, up to 4 kW - 0.8, from 4.8 to 5.2 -1, up to 6 - 1.1. In the calculated economy, the average power of electric motors is 5.83 kW. From here we take the correction factor equal to 1.1
Consumption of materials for TR of electric motors per year.
Table 5.4.1
|
Consumable |
Material characteristic |
Consumption rates, kg. per unit per 1 TR |
Total household chores |
|
|
Brand, standard number |
Assortment |
|||
| GOST 1012–72 | ||||
|
Kerosene lighting |
KO–30, GOST 4753–68 | |||
| CIATIM, GOST 8773–73 | ||||
|
Fasteners |
||||
|
Welding steel wire |
Sv-0.8GS, GOST 2246-70 | |||
|
Sheets and brass rods |
L–63, GOST 15527–70 |
Sheet 0.8´600´1500 mm. |
||
|
Copper strips and sheets |
M-2, GOST 859-78 |
Sheet 0.8´710´1410 mm. |
||
|
Tin-lead solder |
POS-40, GOST 21931-76 | |||
|
Insulating rubberized tape |
1 POA, GOST 2162–78 | |||
|
PVC or linoxin insulating tube |
NK-230, GOST 1535-71, | |||
TLV, GOST 9614–75
Getinax sheet
1, GOST 2718–74
Installation wire
APV, GOST 6323–79
2.5 ... 120 mm 2.
Rosin
A, GOST 19113–84
NTs-132, GOST 6631-74
Putty
KF-003, GOST 10277-76
Primer
Cleaning rags629, GOST 5354–79
Grinding cloth or paper skin
1E, GOST 5009–82
1E, GOST 6456–82
760´30LOG15А80–N
620´50P215A40…3–N
for maintenance and repair of electric motors .
Table 5.4.3
Consumption of materials for maintenance of magnetic starters and circuit breakers for a year of operation.
Table 5.4.4
|
Consumable |
Material characteristic |
Consumption rates, kg. per unit |
household expenses |
|
|
Brand, standard number |
Assortment |
|||
| GOST 1012–72 | ||||
|
Instrument oil |
MVP, GOST 1805–76 | |||
|
Installation wire |
APV, GOST 6323–79 |
2.5 ... 6 mm 2. |
||
|
Fasteners |
||||
|
Phenol-formaldehyde adhesives |
BF–6, BF–2, GOST 12172–74 | |||
|
Cleaning rags |
629, GOST 5354–79 | |||
|
Grinding skin Paper |
1E, GOST 6456–82 |
620´50P215A10–N 620´100P215A4–N |
||
Non-commercial Partnership "Innovations in the electric power industry"
ELECTRIC MOTORS WITH VOLTAGE OVER 1000 V, POWER FROM 100 KW AND MORE
General technical conditions for overhaul
Norms and requirements
Introduction date - 2010-01-11
Moscow
2010
Foreword
Goals and principles of standardization in Russian Federation established by the Federal Law of December 27, 2002 "On Technical Regulation", and the rules for the development and application of organization standards - GOST R 1.4-2004 "Standardization in the Russian Federation. Organization standards. General Provisions".
This standard establishes technical requirements for the repair of electric motors with a voltage of more than 1000 V with a power of 100 kW or more and requirements for the quality of repaired electric motors.
The standard was developed in accordance with the requirements for the standards of power industry organizations “Specifications for the overhaul of power plant equipment. Norms and requirements”, established in section 7 of STO “Thermal and hydraulic power plants. Methodology for assessing the quality of repair of power equipment.
The application of this standard, together with other standards of OAO RAO "UES of Russia" and NP "INVEL", will ensure the implementation mandatory requirements established in the technical regulation on safety power stations and networks.
About the standard
1. DEVELOPED by Closed Joint Stock Company "Central Design Bureau for Modernization and Repair of Power Equipment of Power Plants" (CJSC "TsKB Energoremont")
2 INTRODUCED by the Technical Regulation Commission of NP INVEL
3. APPROVED AND PUT INTO EFFECT by the Order of NP "INVEL" dated December 18, 2009 No.
4. INTRODUCED FOR THE FIRST TIME
STANDARD OF ORGANIZATION NP INVEL
Electric motors with voltage over 1000 V, power from 100 kW and more
General technical conditions for overhaul
Norms and requirements
Introduction date - 2010-01-11
1 area of use
This organization standard:
It is a regulatory document that establishes technical requirements for the repair of asynchronous and synchronous electric motors with a voltage of over 1000 V with a power of 100 kW or more, as well as for the repair of stators and rotors of the above electric motors, aimed at ensuring industrial safety thermal power plants, environmental safety, increasing the reliability of operation and the quality of repairs;
Establishes technical requirements, scope and methods of fault detection, repair methods, control and testing methods for constituent parts and electric motors with a voltage of over 1000 V with a power of 100 kW or more in general during and after repair;
Establishes the volumes, test methods and comparison of quality indicators of repaired electric motors with a voltage of over 1000 V with a power of 100 kW or more with their standard and pre-repair values;
It applies to the overhaul of asynchronous and synchronous electric motors with a voltage of over 1000 V with a power of 100 kW or more (hereinafter referred to as electric motors) of thermal power plants;
Designed for use by generating companies operating at thermal power plants, repair and other organizations that carry out repair maintenance of power plant equipment.
The standard of the organization does not apply to DC motors and special designs (explosion-proof, waterproof, gas-tight, moisture-proof, frost-resistant, chemical-resistant).
2 Normative references
This standard uses Normative references to the following standards and other normative documents:
Federal Law of the Russian Federation of December 27, 2002 No. 184-FZ "On Technical Regulation"
3.2 Symbols and abbreviations
NTD - normative and technical documentation;
OTU - general specifications;
TU - technical conditions.
4 General provisions
4.1 Preparation of electric motors for repair, withdrawal for repair, production repair work and acceptance from repair must be carried out in accordance with the norms and requirements of STO 70238424.27.100.017-2009.
Requirements for repair personnel, guarantees of the repair work manufacturer are established in STO 17330282.27.100.006-2008.
4.2 Fulfillment of the requirements of this standard determines the assessment of the quality of repaired electric motors. The procedure for assessing the quality of repair of electric motors is established in accordance with the standard of the organization of service stations, approved by Order of RAO UES of Russia No. 275 dated April 23, 2007.
4.3 The requirements of this standard, except for capital, can be used for medium and current repairs of electric motors. The following features of their application are taken into account:
Requirements for components and electric motors as a whole in the process of medium or current repairs are applied in accordance with the range and scope of repair work being carried out;
The requirements for the scope and methods of testing and comparing the quality indicators of a repaired electric motor with their normative and pre-repair values during an average repair are applied in full;
The requirements for the scope and methods of testing and comparing the quality indicators of a repaired electric motor with their standard and pre-repair values during current repairs are applied to the extent determined by the technical manager of the power plant and sufficient to establish the operability of the electric motor.
4.4 In case of discrepancy between the requirements of this standard and the requirements of other NTDs issued before the approval of this standard, it is necessary to be guided by the requirements of this standard.
When the manufacturer makes changes to the design documentation for electric motors and when issuing regulatory documents of state supervision bodies, which will entail a change in the requirements for repaired components and for electric motors in general, one should be guided by the newly established requirements of the above documents before making appropriate changes to this standard .
4.5 The requirements of this standard apply to the overhaul of the electric motor during the full service life established in the NTD for the supply of electric motors or in other normative documents. When extending the duration of operation of electric motors in accordance with the established procedure beyond the full service life, the requirements of this standard are applied in the permitted period of operation, taking into account the requirements and conclusions contained in the documents for extending the duration of operation.
5 General technical information
5.1 Electric motors are designed for continuous operation as a drive for station pumps (feed, circulation, condensate, chemical, fire, etc.) of various capacities and pressures, mills for grinding fuels, draft machines (fans and smoke exhausters for various purposes), etc. P.
5.2 Electric motors consist of:
Beds;
stator;
rotor;
windings and insulation;
Brush-contact apparatus (for electric motors with a phase rotor);
rolling bearings;
Plain bearings and thrust bearings;
Air coolers (oil coolers) built into the stator;
Terminal boxes;
Fan on the rotor shaft.
5.3 Structural characteristics, operating parameters and purpose of electric motors must comply with specifications and manufacturer's passports for delivery.
5.4 The standard is based on design documentation manufacturers and takes into account the requirements of GOST 9630, GOST 17494, GOST 20459 and GOST R 51757.
6 General technical requirements
6.1 Requirements for the metrological support of the repair of electric motors:
Measuring instruments used in measurement control and testing should not have errors exceeding those established by GOST 8.051, taking into account the requirements of GOST 8.050;
Measuring instruments used in measurement control and testing must be verified in accordance with the established procedure and are suitable for operation;
Non-standardized measuring instruments must be certified;
It is allowed to replace the measuring instruments provided for in this standard, if this does not increase the measurement error and the safety requirements for the performance of work are observed;
It is allowed to use additional aids controls that expand the possibilities of technical inspection, measurement control and non-destructive testing, not provided for in this standard, if their use increases the effectiveness of technical control;
Equipment, fixtures and tools for processing and assembly must provide accuracy that complies with the tolerances given in the design documentation.
6.2 When performing a major overhaul of the electric motor, the methods, scope and means of technical control are used to determine the compliance of parts, assembly units and the electric motor as a whole with the requirements of paragraphs of this standard.
6.3 Visual inspection without using additional funds control is carried out on the points: ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; , ; ; ; ; ; ; .
6.4 Measurement control is carried out using measuring instruments in accordance with the table.
Table 1
|
Measuring instruments |
|
|
Caliper, threaded template |
|
|
Vernier caliper, micrometer |
|
|
Vernier caliper, caliper, micrometer, slot gauge |
|
|
Micrometer, ruler, profilograph-profilometer |
|
|
Loupe 5 - 7 times magnification, set of probes |
|
|
Megohmmeter |
|
|
Loupe 5 - 7 times magnification, caliper |
|
|
Indicator |
|
|
Calipers |
|
|
Vibrometer, thermometer |
|
|
Indicator, feeler set, caliper |
|
|
BIP-7 device |
|
|
Calipers |
|
|
Ruler, set of probes |
|
|
Megohmmeter |
|
|
Vernier caliper, feeler gauge set |
|
|
Stopwatch |
|
|
Feeler set |
|
|
Vernier caliper, set of probes, megohmmeter |
|
|
Vibrometer |
The place and method of marking must comply with the requirements of the design documentation.
When disassembling the electric motor, it is not allowed to put marks on the seating, sealing and docking surfaces.
6.7 Methods of disassembly (assembly), cleaning, the tools used and the conditions for temporary storage of components must exclude their damage.
6.9 When disassembling (assembling) the components, measures must be taken to temporarily secure the released parts in order to prevent them from falling or moving.
Assembly units of electric motors, bearing parts, rotor shafts and other unpainted surfaces must be cleaned of oil, external contaminants and oxides to the second degree in accordance with GOST 9.402 before fault detection. The internal surfaces of the shields, fans and other unpainted assemblies and components must be cleaned until the paintwork is completely revealed, and if it is damaged, up to the third degree in accordance with GOST 9.402.
Places for connecting the ground wire on the electric motor must be cleaned of paintwork.
The contact surfaces of conductive parts must be protected with cable paper according to GOST 645;
The surfaces of the rotor shaft and the labyrinth grooves on it are wrapped with paraffin paper according to GOST 9569 or sheet rubber according to GOST 7338;
The slip rings of the rotor must be wrapped with electrical insulating cardboard according to GOST 2850;
When working with an open flame within the frontal parts of the stator and rotor windings, the winding insulation must be protected from damage with wet asbestos cardboard according to GOST 2850 and (or) asbestos cloth according to GOST 6102;
When removing the bearings from the rotor shaft, the shaft journals must be protected with an asbestos sheet in accordance with GOST 6102.
It is allowed not to remove the rolling bearings from the rotor of the electric motor to control the fit, if the assembly does not reveal a loose fit and bearing defects.
6.14 Insulation of electric motor windings must be made on the basis of thermosetting electrical insulating materials of heat resistance class not lower than B in accordance with GOST 8865.
Type of insulation - according to the design documentation for a specific electric motor.
Nicks, scuffs, breaks, thread chipping and breaks, corrosion ulcers of the working part of the thread with a depth of more than half the height of the thread profile on more than two threads;
One-sided clearance of more than 1.7% of the turnkey size between the bearing surface of the bolt head (nut) and the surface of the parts after installing the bolt (nut) until it touches the part;
Damage to the heads of bolts (nuts) and slots in the screws, preventing screwing with the necessary effort.
6.20 Threaded connections must be cleaned of dirt, calibrated and lubricated with grease in accordance with GOST 1033.
Taper pins must be replaced if flat largest diameter the pin is buried below the plane of the part by more than 10% of its thickness.
Cylindrical and conical pins must be replaced if their working surface has burrs, nicks, corrosion pits in an area exceeding 20% of the mating area and (or) the threaded part has damage specified in.
Electrodes before use must be calcined in an oven according to the calcination mode recommended for electrodes of this brand.
Signs of a violation are: a change in the color of the outer coating area, solder leakage, an increase in the fragility of the insulation in comparison with other compounds.
table 2
|
Ring risks on the shaft; Weak tightening of the fixing round nut; Temper colors on mating surfaces; Disruption of the lock lug of the washer. Cracks or chipping on rolling parts and treadmills; Separator damage; Nuts, surface dullness, corrosion pits and other defects on the tracks or rolling elements; Radial clearances that go beyond the maximum allowable values; Residual magnetism, which is determined using ferromagnetic powder (crushed iron scale Fe 3 O 4 , sifted through a sieve with a semi-fine mesh 009K according to GOST 6613). To eliminate the defect, install additional gaskets and (or) weld. The compression of parts should be from 15 to 35% of the thickness and distributed evenly around the entire perimeter; The surfaces of sealing parts installed in closed joints must be lubricated with CIATIM-221 grease in accordance with GOST 9433; lubrication of sealing parts installed in flat flanged joints is not allowed; Sealing parts must not have cracks, delaminations, pores, bubbles, tears, brittleness and softening. Electric cardboard gaskets, sleeves, wooden wedges and insulating plastic tubes must be replaced during repairs with the replacement of windings, regardless of the technical condition. 6.37 The materials used for repair must comply with the requirements of the design documentation for the electric motor. The quality of the material must be confirmed by the supplier's certificate. 6.38 The electrodes used in welding and surfacing must comply with the grades specified in technical documentation manufacturer. The quality of the electrodes must be confirmed by a certificate. 6.39 All materials used for the manufacture of components of the electric motor must pass the input control in accordance with GOST 24297. 6.40 Spare parts used for repairs must have accompanying manufacturer's documentation confirming their quality. Before installation, spare parts must be subjected to input control in the scope of the requirements of this standard and the NTD for the repair of a particular electric motor. Measure the amplitude of vibration displacement on the upper cross, bearing supports, motor housing in three directions; Measure the oil temperature of the liners, thrust bearing segments and bearings; Check the efficiency of the cooling system; Check for oil leakage through leaks in the connection of the bearing assembly, inlet and drain pipes, cracks in the oil bath housing. Inspect studs, insulators, terminal boxes; Measure the radial runout at the working end of the shaft flange; Measure the gaps between the shaft and the labyrinth seals; Measure the movement of the rotor in the axial direction (for electric motors with plain bearings). 7 Requirements for components7.1 Stator Defects shall be eliminated by welding and (or) cleaning. Damaged insulation between segments must be repaired, broken parts of segments removed. The blade of the control knife from the force of the hand (from 100 to 120 N) should not enter between the segments to a depth of more than 3 mm. Cleaning the insulation from dirt; drying insulation; Requirements for winding insulation resistance and absorption coefficient in accordance with GOST 183. 7.1.4 Violation of the electrical strength of the body insulation of coils, connecting and output buses is not allowed. To eliminate defects, repair and (or) replace the winding. Requirements for the electrical strength of insulation - according to GOST 11828. 7.2 Rotor Eliminate defects by restoring surfaces, spraying and (or) surfacing, followed by mechanical processing. Runout tolerances of the coupling half and slip rings - according to the design documentation for the electric motor. When tapping with a hammer weighing 0.2 kg, the movement of the balancing weight in any direction is not allowed. The balancing accuracy must correspond to class 4 according to GOST 22061. Residual unbalance after balancing the rotor should not exceed the values given in the design documentation for the electric motor. To eliminate defects, weld or replace the rods. The magnitude of the leakage magnetic flux of the short-circuited winding rods should differ from each other and previously measured by no more than 5%. Defective wire bandages must be replaced. The coils of the new bandage must be laid in accordance with the design documentation. Cleaning the insulation from dirt; drying insulation; Winding insulation repair and replacement. If the insulation resistance is below normal, perform: Winding insulation cleaning; Drying of winding insulation; Repair or replacement of winding insulation. 7.4 Rolling bearings Defective bearings must be replaced. 7.5 Plain bearings and thrust bearings 7.5.1 Cracks, lack of penetration of welding joints in the body are not allowed. Eliminate defects by welding. The work surface must be clean and shiny. The requirements for the insulation resistance of thermometers, the resistance of liners, thrust bearing segments are established by the design documentation. 7.6 Air coolers (oil coolers) 7.6.1 Contamination and damage to the tubes is not allowed. Pollution is eliminated by blowing the tubes with air or steam, and deformations are eliminated by straightening the tubes. To eliminate defects, do: flaring; tube cap; tea leaves; Replacement of sealing parts. The number of plugged and previously plugged tubes should not exceed 10% of the total number of tubes in the air cooler (oil cooler), unless otherwise specified by the manufacturer. 7.7 Shields Elimination of defects by welding is allowed. To eliminate defects, weld bathtubs, replace sealing parts. 8 Requirements for assembly and overhauled electric motor8.1 The assembly of the electric motor must be carried out according to the design documentation for the electric motor. 8.2 Components that meet the requirements of this standard and NTD for a specific electric motor are allowed for assembly. Air gaps between the steel of the rotor and the stator, measured in places located along the circumference of the rotor and shifted relative to each other by an angle of 90 °, or in places specially provided for in the manufacture of the electric motor, should not differ by more than 10% from the average value; The distance between the brush holder and working surface slip rings should be from 1.5 to 4 mm; The contact area of the brush to the contact ring must be at least 80% of its cross-sectional area; Brushes of the same brand and size must be installed on the brush apparatus according to the design documentation for the electric motor; The gaps between the rotor and the bushings of the plain bearings, as well as between its components, must comply with the requirements of the design documentation for the electric motor; Insulation resistance of insulated stand-up bearings relative to foundation slab should not be less than 0.5 MΩ; The insulation resistance of the thrust bearing segments must be no less than in the requirements of the design documentation for the electric motor. In the absence of such instructions in the technical documentation, the vibration of bearings articulated with mechanisms should not exceed the values \u200b\u200bspecified in the table. Table 3
8.7 Noise level of repaired electric motors - according to GOST 16372. 8.8 The repaired electric motors must retain the nominal parameters: power, voltage, current and speed according to the manufacturer's passport data. It is allowed to change the nominal parameters at the request of the customer after confirming them with the appropriate calculations and subject to the requirements of GOST 12139. 9 Tests and quality indicators of reconditioned electric motors9.1 The quality of the repair of the electric motor characterizes the degree of restoration of its operational properties, including reliability, efficiency and maintenance of these qualities for a certain operating time and, therefore, the assessment of the quality of the repair should be based on a comparative comparison of the quality indicators of the repaired electric motor with normative values, determined in accordance with GOST 12139, GOST 28173, the standard for the organization of service stations, approved by Order No. 275 of RAO UES of Russia of April 23, 2007, and specifications for the supply of electric motors. 9.2 The range of quality indicators of electric motors, according to which a comparative comparison of indicators before and after repair is made, is given in the table. Table 4 - Nomenclature of the constituent indicators of the quality of electric motors before and after repair
9.3 Electric motors repaired without changing the parameters are subject to acceptance tests in accordance with GOST 183 and RD 34.45-51.300-97. 9.4 Repaired electric motors with parameter changes are subject to type tests according to GOST 11828. 9.5 Methods for acceptance testing of electric motors must comply with GOST 7217, GOST 9630, GOST 10169, GOST 11828. 9.6 When issuing an electric motor from repair, the following measurements and tests must be performed: Measure the movement of the rotor in the axial direction (for electric motors with plain bearings); Measure the air gap between the steel of the rotor and the stator, if the design of the electric motor allows; Measure the gap between the shaft and the labyrinth seals; Measure the radial runout at the working end of the shaft; Measure the insulation resistance and the absorption coefficient of the stator winding; For synchronous and slip-ring motors, measure the insulation resistance of the rotor winding; Measure the resistance of the phases of the stator and rotor windings to direct current (the resistance to direct current of the rotor winding is measured for synchronous electric motors and asynchronous electric motors with a phase rotor); Carry out high voltage tests of the stator and rotor windings (for synchronous electric motors and electric motors with a phase rotor); Check the insulator studs; Measure clearances in bearing assemblies; Measure the insulation resistance of the thrust bearings; Check the oil level in the crosses, oil baths, bearing chambers; Check the absence of oil leakage through leaks in the connection of the bearing assembly, inlet and drain pipes, cracks in the oil bath housing; Measure the temperature of the cooling water; Check the operation of the electric motor at idle for at least 1 hour, measure the idle current; Measure the amplitude of vibration displacement or the root-mean-square value of the vibration velocity on the upper cross, bearings, motor housing in three directions; Check the operation of the electric motor under load with the power consumed from the network at least 50% of the rated power for at least 48 hours; Measure the temperature of oil, bearings, liners, segments; Measure the temperature of the stator winding; Measure the temperature of the stator core; Check the efficiency of the cooling system. 9.7 The value of the test voltage with a frequency of 50 Hz is taken according to the table. Duration of test voltage application 1 min. Table 5
9.8 The smallest allowable values of winding insulation resistance are given in the table. Table 6
9.9 For the measurement of insulation resistance, the one-minute measurement method may be used. 9.10 Measurement of the insulation resistance of the stator windings is carried out with a megger for a voltage of 2500 V - with a rated voltage of the winding above 1000 V, with a megger for a voltage of 1000 V - with a rated voltage of the winding from 500 to 1000 V, with a megger for a voltage of 500 V - with a rated voltage of the winding up to 500 V , accuracy class is not worse than 2.5. 9.11 Measurement of the insulation resistance of the rotor winding of asynchronous electric motors and electric motors with a phase rotor is carried out with a megohmmeter for a voltage of 1000 V (500 V is allowed). When repairing electric motors with replacing the rotor winding, the insulation resistance must be at least 0.2 MΩ. When repairing an electric motor without replacing the rotor winding, the insulation resistance is not standardized. 9.12 Measurement of the resistance of bearing assemblies is carried out with a megohmmeter for a voltage of 1000 V. 9.13 Applicable for testing measuring instruments must comply with GOST 11828. 9.14 Measurement of the resistance of the stator and rotor windings is carried out at a temperature of 10 to 30 °C. 9.15 Reduced to the same temperature, the measured resistance values of the various phases of the windings should not differ from each other and from the initial values by more than 2%. 9.16 Permissible values of clearances in the plain bearings of the electric motor are given in table 7 |
0,100 - 0,195 |
0,150 - 0,285 |
0,260 - 0,530 |
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|
St. 180 to 260 incl. |
0,120 - 0,225 |
0,180 - 0,300 |
0,30 - 0,60 |
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|
St. 260 to 360 incl. |
0,140 - 0,250 |
0,210 - 0,380 |
0,34 - 0,68 |
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|
St. 360 to 600 incl. |
0,170 - 0,305 |
0,250 - 0,440 |
0,36 - 0,76 |
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9.17 If it is impossible to carry out any tests during delivery for repair and acceptance from repair, the scope and methods of testing, as well as the conditions for their implementation, are established by the customer together with the repair contractor, depending on the type, purpose of the electric motor, and the possibility of testing.
10 Safety requirements
10.1 Special devices for lifting and transporting (eye bolts, lugs, holes) on the repaired components and parts of the electric motor must fully comply with the requirements of the design documentation.
10.2 When repairing electric motors (components), safety requirements, including fire safety, established in GOST 12.2.007.0 must be observed.
10.4 Vibration safety criteria - according to GOST 12.1.012.
11 Conformity assessment
11.1 Conformity assessment is carried out in accordance with STO 17230282.27.010.002-2008.
11.2 Assessment of compliance with the technical requirements, the scope and methods of fault detection, repair methods, methods of control and testing for components and electric motors as a whole with the norms and requirements of this standard is carried out in the form of control during the repair process and upon acceptance into operation.
11.3 In the process of repair, control over the fulfillment of the requirements of this standard for components and electric motors as a whole is carried out during repair work, performance technological operations repairs and node tests.
When accepting repaired electric motors for operation, the results of acceptance tests, work during the period of controlled operation, quality indicators, established quality assessments of repaired electric motors and performed repair work are monitored.
11.4 The results of the conformity assessment are characterized by quality assessments of the repaired electric motors and the repair work performed.
11.5 Control over compliance with the norms and requirements of this standard is carried out by bodies (departments, divisions, services) determined by the generating company.
11.6 Control over compliance with the norms and requirements of this standard is carried out according to the rules and in the manner established by the generating company.
Bibliography
Yu.B. Trofimov
Performers
Yu.P. Kosinov
Yu.B. Trofimov
Performers
Yu.P. Kosinov
Abstract on the topic:
"Maintenance and current repair of electric motors"
Maintenance (TO) of electric motors. 3
Current repair (TR) of electric motors. 3
Three times impregnation of windings with varnish modified with inhibitors 7
Encapsulation of frontal parts of electric motors. eight
List of used sources.. 13
Maintenance (TO) of electric motors
Maintenance is carried out at the installation site without dismantling and disassembly. The scope of maintenance includes: cleaning the electric motor from dust and dirt; checking the serviceability of grounding, fixing the electric motor and its elements, the degree of heating and the level of vibration and noise, the reliability of contact connections; measurement of insulation resistance and elimination of detected faults. For motors with a phase rotor, the condition of the slip rings and the brush mechanism is checked.
The terms of maintenance of electric motors depend on the characteristics of the premises and the working machines with which they work. Maintenance of electric motors of series 4A, D, AO2SKh is carried out once every three months, except for electric motors installed on grain crushers, threshers, presses, feed grinders (dusty wet rooms), for which maintenance is carried out once every one and a half months. The same maintenance intervals have electric motors operating on outdoors or under a canopy. For engines of milk vacuum pumps and pasteurizers (especially damp rooms), maintenance is performed once every two months.
The frequency of maintenance for electric motors of the AO2 series installed in dry and humid, as well as damp rooms, for electric motors used in dusty and especially damp rooms, is determined in accordance with the PPRE - a system of preventive maintenance of electrical equipment.
Current repair (TR) of electric motors
They are carried out either at the place of their installation, or at a maintenance point, in a workshop, etc. Current repairs at the installation site of electrical equipment are carried out by specialized mobile teams.
In accordance with the PPR, the scope of the current repair of the electric motor includes: cleaning from dust and dirt, disconnecting from the supply wires and grounding, dismantling at the installation site and disassembling, cleaning the winding, measuring the insulation resistance of the winding and, if necessary, drying the winding, washing the bearings, checking and replacement if necessary, repair or replacement of damaged lead wires of the winding and terminal board, terminal boxes, assembly, lubrication of bearings, idle test, painting and, if necessary, installation of the electric motor on the workplace, alignment with the working machine and testing under load.
For electric motors with a phase rotor, the condition of the slip rings is checked, if necessary, they are grooved and polished, the brush mechanism is adjusted and, if necessary, the brushes are replaced.
When drying the motor windings, moisture is removed from the pores and cracks of the winding, but the cracks and pores themselves remain in the varnish film. This means that the probability of fairly rapid wetting of the motor winding during its "breathing" during operation remains, and, consequently, the probability of breakdown. Elimination of pores and cracks in the varnish film of the winding conductors makes it possible to avoid its moistening for a long time. Cracks and pores can only be repaired by impregnating the winding in lacquer.
Winding impregnation increases its reliability, but complicates the repair technology, requires impregnating baths, varnish storage containers, etc. In addition, the time spent by the electric motor in repair increases, it can be more than the downtime between work cycles. In this case, it will be necessary to replace the repaired electric motor with a backup one. Therefore, in each specific case, before the current repair, it is necessary to conduct a thorough diagnosis of the state of the electric motor and, based on the data obtained, decide on the scope and location of the repair.
The frequency of current repairs of electric motors of series 4A, D, AO2SKh in accordance with the PPRE is 24 months, with the exception of electric motors installed on milk vacuum pumps and pasteurizers in especially damp rooms in which the humidity exceeds 98%, in this case, the frequency of current repairs is 18 months.
The periodicity of TR for electric motors of the A02 series is 24 months for dry, damp (humidity up to 75%) and damp rooms and 18 months for dusty and especially damp rooms (humidity up to 98%), excluding electric motors of grain crushers, threshers, presses, feed grinders, for which frequency is 12 months. Electric motors of the AO2 series operating in the open air or under a canopy have the same frequency of TR.
The PPRE system determines the frequency of maintenance and repair in relation to the room and the working machine for which the electric motor is used. The influence of the operating mode of the electric motor on the change in the characteristics of the winding insulation is not taken into account when determining the frequency of maintenance and TR. In addition, PPR does not take into account the life of the electric motor. In accordance with the PPRE, a new electric motor that has been subjected to maintenance or TR for the first time, and an electric motor that has already repeatedly passed TO and TR have the same frequency. The frequency of maintenance and repair of electric motors installed on working machines after a major overhaul or modernization is not specified.
Under these conditions, the importance of electrical equipment diagnostics and the role of the heads of the electrical service of the economy in the preparation of monthly and annual schedules Maintenance and repair of electrical equipment.
Qualitatively performed diagnostics of the electrical equipment of the economy will allow you to adjust the timing of maintenance and current repairs of electrical equipment. With the help of diagnostics, it is possible to identify and take out of operation for repair (modernization) or for decommissioning electrical equipment that has exhausted its resource and has maximum permissible reliability parameters. As a result, the risk of a sudden failure of electrical equipment and an emergency stop is eliminated. technological process.
Modernization of electrical equipment that was put into repair in a timely manner will increase its reliability and, as a result, ensure the continuity of the technological process of agricultural production. As a result of diagnostics, a decision can be made to extend the time between maintenance and repair for electrical equipment that has high parameters reliability, which will save the cost of maintenance of electrical equipment.
Consider measures to improve the operational reliability of electric motors.
The main reasons for the failure of electric motors used in agricultural production: non-compliance with harsh environmental conditions; inconsistency or lack of protection against open-phase modes of operation and emergency overloads; insufficient level of exploitation.
To eliminate the first reason, the following measures are taken: electric motors of increased reliability are produced; modernize electric motors of old series during repairs; take out electric motors outside the limits of the damp corrosive environment.
Increasing the reliability of electric motors, factories produce highly specialized versions for agricultural production. Electric motors of the second series of agricultural design AO2SH have justified themselves well in operation.
When working in livestock buildings, the service life of electric motors of agricultural design reaches 6 ... 8 years, and the second series of general industrial design - only 1 ... 2 years.
In the fourth series of general industrial electric motors, the same insulating and active materials are used as in AO2SKh motors. Therefore, electric motors of the 4A and A02CX series operate with the same reliability. The difference between the manufactured electric motors of a specialized design 4АХ is only in anodizing or nickel plating of the motor mounting parts and better painting.
Upgraded electric motors of the fourth series 4AM have increased reliability. The domestic electrical industry, together with the countries of the socialist community, has begun to produce a new series of AI (international) engines, the characteristics and reliability of which have been further improved.
Thus, modern electric motors of general industrial design are universal, since they can be used in especially damp livestock buildings with a chemically active environment, in which the humidity content is 80 ... 100%, ammonia - 2 ... 140 mg / m3, hydrogen sulfide - 10...90 and carbon dioxide- 0.03...0.88 mg/m3, dust content - up to 240 g/m3.
In agricultural production, a variety of series of electric motors are used, including the old ones - A, AO and A2, AO2.
During major and current repairs, it is desirable to upgrade the old series of electric motors. Usually, electric machine-building plants in the manufacture of electric motors use double impregnation of the windings. Electrical repair plants sometimes deviate from repair technology and use only a single impregnation of the winding, which significantly reduces the reliability of motors. As the simplest modernization of electric motors during their repair, one can consider the use of not two, but three times impregnation.
Three times impregnation of windings with varnish modified with inhibitors
This proposal by V.I. Charykov - the first type of the simplest modernization, which increases the reliability of electric motors during current repairs. The inhibitor, diffusing into the lacquer film and filling its pores, prevents the penetration of moisture. For research, we used chromate and BDN inhibitors developed by ChIMESKh under the guidance of O.I. Golyanitsky. The best results were obtained when using a BDN inhibitor - a mixture of diethylaniline, benzotriazole and paranitrophenol dissolved in acetone. When impregnating the winding, GF-92KhS enamel modified by adding 6% (by weight of the enamel) of an inhibitor was used.
The rationale for the need for periodic maintenance of IM is given. An approximate list of works on maintenance of AD is proposed
Asynchronous motors are characterized by very high reliability, high uninterrupted operation (subject to the permissible duty cycle).
However, this does not mean that "asynchronous" are eternal. Therefore, it is recommended that each plant has a maintenance schedule. induction motors. The list of works during maintenance of asynchronous motors can be as follows:
1. External inspection and assessment of the condition of the mechanical part
Maintenance of an asynchronous electric motor should begin with its detailed external inspection. First of all, the presence of obvious faults is determined. The motor housing should be cleaned of dirt and dust with a steel brush. It must not be chipped or damaged. Due to vibrations and dynamic loads, as well as irregularities and defects in the mounting site, it often happens that one of the mounting "paws" breaks off. Such an engine is rejected and not allowed for further operation.
AT without fail you should check the presence of the terminal box cover, as well as the cover covering the rotor terminals for motors with a phase rotor. These lids should close tightly, without gaps. Their crushing and damage are not allowed.
Each asynchronous electric motor must have a nameplate on the body - a plate with information about the rating parameters. It is necessary to control the readability of all inscriptions on the nameplate and, if necessary, restore them in order not to have “unidentified” electric motors in the household.
When performing maintenance, the engine must be disconnected from the transmission: remove the drive belt, chain or half-coupling. After that, turn the shaft by hand. It should turn with an effort due only to the inertia of the rotor, extraneous sounds, rattle and crunch should be absent.
It is necessary to open the casing hiding the motor impeller (when closed). The impeller must not dangle, have play in any direction, the locking screw must be tightened.
The motor shaft must not move in the radial and axial directions, and the sprocket or pulley on the shaft must be securely fastened and not dangling. All bolted connections must be pulled through and the thread must not be stripped. Defective parts and fasteners must be replaced.
Next, you need to open the covers of the bearing assemblies. The condition of bearings and bearing seats is determined visually. Cracks, chips of bearing rings, its incorrect position relative to the shaft (misalignment) are excluded. Before closing, the bearing assembly is filled with grease (oil or special grease). It is generally recommended to monitor the presence and condition of lubricant in bearing assemblies every shift.
2. External inspection and assessment of the state of the electrical part
To assess the condition of the stator terminals and the current collector of the rotor, the engine covers are opened. The insulation of the stator terminals must be intact, without cracks or damage, otherwise the insulation must be restored with electrical tape and keeper tape. The terminal block, if present, must not be melted or damaged - otherwise it must be replaced.
The tips of the stator terminals may be oxidized or have carbon deposits on the surface - this is a sign of poor electrical contact. In the presence of such defects, the tips should be cleaned to metal and the windings reconnected according to the required scheme. The cavity of the motor terminal box should be carefully cleaned of dust and dirt.
The residual value of the current-collecting rotor brushes of motors with a phase rotor must be at least 4 mm. Their contact surface must be flat and fit snugly against the slip ring. Chips and cracks on the brushes are excluded. Defective brushes must be replaced. Before installation, they are ground under the surface of the slip ring with glass paper.
Collector rings should be cleaned of dust and dirt with a rag soaked in kerosene. Seizures, damage to slip rings are not allowed. The cause of such defects may be the limiting wear of the brushes not noticed in time.
Finally, it is necessary to check the condition of the grounding conductor of the electric motor. Its cores must be intact, without damage, and the bolt fasteners of the tips must be securely tightened.
3. Measurements and tests
At this stage, using a megohmmeter, the insulation resistance of the stator windings is checked, and for motors with a phase rotor, the rotor windings are also checked. Electrical resistance stator windings are checked relative to the motor housing, and the resistance of the rotor windings is checked relative to the working shaft. At operating temperature winding insulation resistance of 0.5 MΩ or more is considered normal. In practice, the insulation resistance of serviceable electric motors is calculated in tens of Mohms.
Next, you need to measure the resistance of the stator windings to direct current. The resistances should be the same in phase, this indirectly indicates the absence of interturn short circuits. For this measurement, it is better to use not a multimeter, but a device with more high class accuracy, since the resistance of the DC windings is calculated in fractions of an ohm.
After making the above measurements, the engine is connected to the network, its covers are closed. The engine starts at idle. The absence of vibrations, beats of the working shaft is checked, the currents are measured phase by phase and correlated with each other idle move. By hand, the presence / absence of heating of the motor housing is checked for at least 15 minutes of operation.
Some rise in temperature is normal and the extent to which it is allowed is determined by the insulation resistance class. But, for example, an increase in the temperature of the case to 100 ° C clearly indicates any problems in the operation of the electric motor.
Only after that the engine is connected to the transmission of the working mechanism and is included in the work under load. Maintenance can be considered completed.
4. General remarks
The main purpose of maintenance is prevention and timely detection faults. If the detected defects are not large and serious, a decision is made to eliminate them on the spot during maintenance. For major and responsible repairs, the engines are delivered to a specially equipped electrical workshop.
In a systematic maintenance need not only asynchronous electric motors. But it is precisely in their relation that this necessity is often neglected.
However, the lack of timely maintenance is fraught for the engine with serious breakdowns and malfunctions, the elimination of which can take a lot of time and effort. There may be mechanical damage iron of the stator, the motor winding may become completely unusable, even a fire may occur in the box or in the working cavity of the motor.
The list of works during maintenance, in agreement with the chief engineer or chief power engineer of the enterprise, does not have to be exactly the same as proposed in this article. Working conditions are of decisive importance: ambient humidity, temperature, dustiness of the room and, finally, the intensity of work. The same factors should be taken into account when determining the frequency of maintenance of asynchronous motors.
