Global one-stop procurement platform for industrial spare parts.
support01@okmarts.com service@okmarts.com hydraulic@okmarts.com
Display the website inEN
EN
translate to EN
EN
translate to ES
ES
translate to العربية
العربية
All
Danfoss
Danfoss
Johnson Controls
Johnson Controls
Senex
Senex
Huba Control
Huba Control
HACH
HACH
Meas
Meas
All Brands
All Brands
    • a
    • b
    • c
    • d
    • e
    • f
    • g
    • h
    • i
    • j
    • k
    • l
    • m
    • n
    • o
    • p
    • q
    • r
    • s
    • t
    • u
    • v
    • w
    • x
    • y
    • z
    • 3
    • 7

    The reason for the failure of the multi-line air-conditioning compressor is revealed!

    1 Overview The failure of motor compressor (hereinafter referred to as compressor) can be divided into motor failure and mechanical failure (including crankshaft, connecting rod, piston, valve plate, cylinder head gasket, etc.). Mechanical failures often overload the motor and even block it, which is one of the main causes of motor damage. The damage of the motor is mainly manifested as the destruction (short circuit) and open circuit of the stator winding insulation. After the stator winding is damaged, it is difficult to be found in time, which may eventually cause the winding to burn out. After the winding is burned, some phenomena or direct causes that caused the burnout are masked, making post-mortem analysis and cause investigation difficult. However, the operation of the motor is inseparable from normal power input, reasonable motor load, good heat dissipation and protection of the winding enameled wire insulation. Starting from these aspects, it is not difficult to find that the reasons for the burning of the winding are as follows: (1) Abnormal load and locked rotor; (2) Short circuit of winding caused by metal chips; (3) Contactor problem; (4) Absence of power supply phase and abnormal voltage; (5) Insufficient cooling; (6) Use the compressor to evacuate. In fact, motor damage caused by multiple factors is more common. 2 Abnormal load and stall The motor load includes the load required to compress the gas and the load required to overcome mechanical friction. If the pressure ratio is too large or the pressure difference is too large, the compression process will be more difficult. The increased frictional resistance caused by lubrication failure and the motor stall in extreme cases will greatly increase the motor load. "Lubrication failure and increased frictional resistance are the primary causes of abnormal loads" Dilution of the lubricating oil back to the liquid, overheating of the lubricating oil, coking and deterioration of the lubricating oil, and lack of oil will destroy the normal lubrication and cause lubrication failure. Dilute the lubricating oil back to the liquid, which affects the formation of the normal oil film on the friction surface, and even wash away the original oil film, increasing friction and wear. Overheating of the compressor will cause the lubricating oil to dilute or even coke at high temperature, affecting the formation of normal oil film. The oil return of the system is not good, the compressor lacks oil, and naturally cannot maintain normal lubrication. The crankshaft rotates at a high speed and the connecting rod and piston move at a high speed. The friction surface without oil film protection will quickly heat up. Local high temperature makes the lubricating oil evaporate or scorch quickly, making lubrication of this part more difficult. It can cause serious local wear within a few seconds. Lubrication failure, local wear, and greater torque are required to rotate the crankshaft. Low-power compressors (such as refrigerators and household air-conditioning compressors) often have blocked torque (the motor cannot rotate) after lubrication failure due to the low torque of the motor, and enter the "locked-thermal protection-locked-rotation" dead cycle. The motor burns only Time issue. The high-power semi-hermetic compressor motor has a large torque, and local wear will not cause stalling. The motor power will increase with load within a certain range, which will cause more serious wear and even cause the cylinder to bite Inside), severe damage such as broken connecting rod. 3 Short circuit caused by metal shavings The metal shavings in the winding are the culprits of short circuit and low ground insulation value. The normal vibration of the compressor during operation and the twisting of the windings caused by the electromagnetic force at each start will promote the relative movement and friction between the metal shavings interposed between the windings and the winding enameled wire. Sharp metal chips can scratch the insulation of the enameled wire and cause a short circuit. Sources of metal shavings include copper pipe shavings left during construction, welding slag, metal shavings from internal compressor wear and parts damage (such as broken valve discs). For hermetic compressors (including hermetic scroll compressors), these metal chips or debris will fall on the windings. For semi-hermetic compressors, some particles will flow in the system with gas and lubricating oil, and finally gather in the windings due to magnetism; and some metal chips (such as those caused by bearing wear and motor rotor and stator wear (bore sweeping)) It falls directly on the winding. It is only a matter of time before a short circuit occurs after metal chips have accumulated in the winding. 4 Contactor problem The contactor is one of the important components in the motor control loop. Unreasonable selection can destroy the best compressor. It is extremely important to select the contactor correctly according to the load. The contactor must be able to meet demanding conditions such as fast cycling, continuous overload and low voltage. They must have a large enough area to dissipate the heat generated by the load current, and the selection of contact materials must prevent welding under high current conditions such as starting or blocking. In order to be safe and reliable, the compressor contactor should simultaneously disconnect the three-phase circuit. Copeland does not recommend the method of disconnecting the phase circuit. In the United States, the contactor approved by Copeland must meet the following four items: 1. The contactor must meet the working and testing guidelines specified in ARI Standard 780-78 "Special Contactor Standard". 2. The manufacturer must ensure that the contactor can close at 80% of the lowest nameplate voltage at room temperature. 3. When using a single contactor, the rated current of the contactor must be greater than the motor nameplate current rating (RLA). At the same time, the contactor must be able to withstand the motor stall current. If there are other loads downstream of the contactor, such as motor fans, it must also be considered. 4. When two contactors are used, the sub-winding stall rating of each contactor must be equal to or greater than the compressor half-winding stall rating. The rated current of the contactor cannot be lower than the rated current on the compressor nameplate. Contactors with small specifications or inferior quality cannot withstand compressor start-up, stalling and high-current impact at low voltage, and are prone to single-phase or multi-phase contact jitter, welding or even falling off, causing motor damage. Contactors with jittering contacts frequently start and stop the motor. The motor starts frequently, and the huge starting current and heat will aggravate the aging of the winding insulation layer. At each start, the magnetic torque causes the motor windings to move slightly and rub against each other. If there are other factors (such as metal shavings, lubricating oil with poor insulation, etc.), it is easy to cause short circuit between windings. The thermal protection system is not designed to prevent such damage. In addition, jittery contactor coils are prone to failure. If the contact coil is damaged, it is easy to appear single-phase state. If the selection of the contactor is too small, the contacts cannot withstand the arc and the high temperature due to frequent start-stop cycles or unstable control circuit voltage, which may be welded or detached from the contact holder. The welded contacts will produce a permanent single-phase state, making the overload protector continuously cycle on and off. Therefore, when the motor burns out, checking the contactor is an essential process. The contactor is an important cause of motor damage that is often forgotten. 5 Power failure and abnormal voltage Abnormal voltage and phase loss can easily destroy any motor. The power supply voltage variation range cannot exceed ± 10% of the rated voltage. The voltage imbalance between the three phases cannot exceed 5%. High-power motors must be independently powered to prevent low voltages when other high-power equipment on the same line starts and runs. The motor power cable must be able to carry the rated current of the motor. If the compressor is running when a phase loss occurs, it will continue to run but will have a large load current. The motor windings will quickly overheat and the compressor will be thermally protected under normal conditions. When the motor winding is cooled to the set temperature, the contactor will be closed, but the compressor will not start, it will stall, and enter "Block-rotation-thermal protection-lock-rotation" endless loop. 6 Insufficient cooling Compressors with higher power are generally return air cooled. The lower the evaporation temperature, the lower the system mass flow. When the evaporation temperature is very low (exceeding the manufacturer's regulations), the flow is not enough to cool the motor, and the motor will run at a higher temperature. Air-cooled compressors (generally no more than 10HP) have a small dependence on the return air, but they have clear requirements on the compressor's ambient temperature and cooling air volume. A large amount of refrigerant leakage will also reduce the system mass flow, and the cooling of the motor will also be affected. Some unattended cold storage, etc., often find that a large amount of refrigerant leaks only when the cooling effect is poor. After the motor is overheated, frequent protection will occur. Some users do not check the cause in depth or even short-circuit the thermal protector, which is a very bad thing. Before long, the motor will burn out. Compressors have a range of safe operating conditions. The main considerations for safe operating conditions are the load and cooling of the compressor and motor. Due to the different prices of compressors in different temperature zones, it has been common to use compressors in the domestic refrigeration industry in the past. With the growth of professional knowledge and the improvement of economic conditions, the situation has improved significantly. 7 Use the compressor to evacuate The open-type refrigeration compressor has been forgotten, but there are still some on-site construction workers in the refrigeration industry who have retained the past habit of using the compressor to vacuum. This is very dangerous. Air acts as an insulating medium. After evacuating the airtight container, the discharge phenomenon between the electrodes inside easily occurs. Therefore, with the deepening of the vacuum in the compressor casing, the insulation medium is lost between the exposed terminals in the casing or the windings with slight damage to the insulation layer. Once energized, the motor may be short-circuited and burned in an instant. If the case leaks, it may cause electric shock. Therefore, it is forbidden to use the compressor to evacuate, and when the system and the compressor are in a vacuum state (the refrigerant has not been added after the vacuum has been drawn), it is strictly prohibited to energize the compressor. 8 Summary After the motor burned out, the phenomenon of winding damage was masked, which caused certain difficulties in fault analysis. However, the root cause of compressor motor damage will not disappear. 1. Abnormal load caused by poor lubrication or failure or even blocked rotation, insufficient heat dissipation will shorten the life of the winding; 2. The inclusion of metal chips in the winding provides convenience for short circuit; 3. The welding of the contactor will make the protection of the compressor impossible to implement; 4. If the power supply on which the motor runs is abnormal, any motor will be destroyed fundamentally; 5. Vacuuming with the compressor may cause internal terminal discharge

    Recent related posts

    The reason for the failure of the multi-line air-conditioning compressor is revealed!

    06/14/2020

    The reason for the failure of the multi-line air-conditioning compressor is revealed!

    The failure of motor compressor (hereinafter referred to as compressor) can be divided into motor failure and mechanical failure (including crankshaft, connecting rod, piston, valve plate, cylinder head gasket, etc.). Mechanical failures often overload器2䀀ￜ皥䖒皦즠Ʋ煔क़㲈Ʋ䌁皦ᮔDž༬皧煞क़Ѐ呄ᠾ鹨់༹皧ࠄ00령ꐱ댁珵뛐珵Љ䕄ྦ￿￿뤂ᐱ뚜珵ᴴᏩ呄ᠾ퍘ᒥ鹨់ᩄꋔྦ瑉浥巠皱㙲皦抐皱巠皱੨皦柘皱ￜ皥ب巠皱㙲皦忈皱੨皦柘皱즠Ʋǜ勁皦즠ƲبǜV /펔B䌁皦 ᮔDž'鱤džၜ먢䇨珵呈ᠾ뤂ᐱ⿇⬿먲僧ᐱ㥲ᐲ�僬㣢ᐲᠾ랖僧ݠ識�僬㣢ᐲ臆S㥲ᐲᬄğ識理艏S杴 識杴 㥲ᐲ

    What are the advantages of air spring

    06/14/2020

    What are the advantages of air spring

    The air spring shock absorber is the vibration isolator with the highest vibration isolation efficiency at this stage, which is better than the yellow elastic and vulcanized rubber. The air spring shock absorber is composed of a brake air chamber, a vulca器2䀀ￜ皥䖒皦즠Ʋ嫜ི㲈Ʋ䌁皦ᮔDž༬皧嫦ིЀ呄ᠾ鹨់༹皧ࠄ00령ꐱ댁珵뛐珵Љ䕄ྦ￿￿뤂ᐱ뚜珵ᴴᏩ呄ᠾ퍘ᒥ鹨់ᩄꋔྦ瑉浥巠皱㙲皦抐皱巠皱੨皦柘皱ￜ皥ب巠皱㙲皦忈皱੨皦柘皱즠Ʋǜ勁皦즠ƲبǜV /펔B䌁皦 ᮔDž'鱤džၜ먢䇨珵呈ᠾ뤂ᐱ⿇⬿먲僧ᐱ㥲ᐲ�僬㣢ᐲᠾ랖僧׈識�僬㣢ᐲ臆S㥲ᐲᬄğ識理艏S杴 識杴 㥲ᐲ

    Throttling mechanism

    06/14/2020

    Throttling mechanism

    The throttling mechanism is one of the important components in the refrigeration device. Its function is to reduce the saturated liquid (or supercooled liquid) under the condensing pressure in the condenser or accumulator to the evaporating pressure and e器2䀀ￜ皥䖒皦즠Ʋ煔क़㲈Ʋ䌁皦ᮔDž༬皧煞क़Ѐ呄ᠾ鹨់༹皧ࠄ00령ꐱ댁珵뛐珵Љ䕄ྦ￿￿뤂ᐱ뚜珵ᴴᏩ呄ᠾ퍘ᒥ鹨់ᩄꋔྦ瑉浥巠皱㙲皦抐皱巠皱੨皦柘皱ￜ皥ب巠皱㙲皦忈皱੨皦柘皱즠Ʋǜ勁皦즠ƲبǜV /펔B䌁皦

    Thermal expansion valve

    06/14/2020

    Thermal expansion valve

    Thermal expansion valve Thermal expansion valves are commonly used in Freon refrigeration systems. Through the function of the temperature sensing mechanism, they automatically change with the temperature change of the refrigerant at the outlet of the ev器2䀀ￜ皥䖒皦즠Ʋ嫜ི㲈Ʋ䌁皦ᮔDž༬皧嫦ིЀ呄ᠾ鹨់༹皧ࠄ

    The harm and elimination method of air intake in refrigeration system

    06/14/2020

    The harm and elimination method of air intake in refrigeration system

    The harm and elimination method of air intake in refrigeration system 1 Overview In the refrigeration system, the so-called non-condensable gas means that when the refrigeration system is working, at a specific temperature and pressure in the condense器2䀀ￜ皥䖒皦즠Ʋ煔क़㲈Ʋ䌁皦ᮔDž༬皧煞क़Ѐ呄ᠾ鹨់༹皧ࠄ00령ꐱ댁珵뛐珵Љ䕄ྦ￿￿뤂ᐱ뚜珵ᴴᏩ呄ᠾ퍘ᒥ鹨់ᩄꋔྦ瑉浥巠皱㙲皦抐皱巠皱੨皦柘皱ￜ皥ب巠皱㙲皦忈皱੨皦柘皱즠Ʋǜ勁皦즠ƲبǜV /펔B䌁皦 ᮔDž'鱤džၜ먢䇨珵呈ᠾ뤂ᐱ⿇⬿먲僧ᐱ㥲ᐲ�僬㣢ᐲᠾ랖僧Ӡ識�僬㣢ᐲ臆S㥲ᐲᬄğ識理艏S杴 識杴 㥲ᐲ

    Precautions for the operation of cold storage equipment

    06/14/2020

    Precautions for the operation of cold storage equipment

    Precautions for the operation of cold storage equipment 1. For the evaporator of the air-cooled machine: always check the defrosting situation, whether the defrosting is timely and effective, it will affect the cooling effect and cause the liquid return 器2䀀ￜ皥

    Internal balance type thermal expansion valve

    06/14/2020

    Internal balance type thermal expansion valve

    Internal balance type thermal expansion valve The internal balance type thermal expansion valve is composed of valve body, push rod, valve seat, valve needle, spring, adjusting rod, temperature sensor, connecting pipe, sensing diaphragm and other compone器

    External balance thermal expansion valve

    06/14/2020

    External balance thermal expansion valve

    The difference between the external balance type thermal expansion valve and the internal balance type in structure and installation is that the space under the diaphragm of the external balance type valve is not in communication with the outlet of the va器2䀀ￜ皥䖒皦즠Ʋ嫜ི㲈Ʋ䌁皦ᮔDž༬皧嫦ིЀ呄ᠾ鹨់༹皧ࠄ00령ꐱ댁珵뛐珵Љ䕄ྦ￿￿뤂ᐱ뚜珵ᴴᏩ呄ᠾ퍘ᒥ鹨់ᩄꋔྦ瑉浥巠皱㙲皦抐皱巠皱੨皦柘皱ￜ皥ب巠皱㙲皦忈皱੨皦柘皱즠Ʋǜ勁皦즠ƲبǜV /펔B䌁皦 ᮔDž'鱤džၜ먢䇨珵呈ᠾ뤂ᐱ⿇⬿먲僧ᐱ㥲ᐲ�僬㣢ᐲᠾ랖僧ۖ識�僬㣢ᐲ臆S㥲ᐲᬄğ識理艏S杴 識杴 㥲ᐲ

    Electronic expansion valve

    06/14/2020

    Electronic expansion valve

    Electronic expansion valve The electronic expansion valve is a speed type and is used in an intelligently controlled inverter air conditioner. The advantages of the electronic expansion valve are: large flow adjustment range; high control accuracy; suita器2䀀ￜ皥䖒皦즠Ʋ煔क़㲈Ʋ䌁皦ᮔDž༬皧煞क़Ѐ呄ᠾ鹨់༹皧ࠄ00령ꐱ댁珵뛐珵Љ䕄ྦ￿￿뤂ᐱ뚜珵ᴴᏩ呄ᠾ퍘ᒥ鹨់ᩄꋔྦ瑉浥

    Cold storage operation management and compressor common fault handling

    06/14/2020

    Cold storage operation management and compressor common fault handling

    Cold storage operation management and compressor common fault handling 1. Startup and preparations Before starting the machine, check whether the valves of the unit are in the normal starting state, and check whether the cooling water source is suffic器2䀀ￜ皥䖒皦즠Ʋ嫜ི㲈Ʋ䌁皦ᮔDž༬皧嫦ིЀ呄ᠾ鹨់༹皧ࠄ00령ꐱ댁珵뛐珵Љ䕄ྦ￿￿뤂ᐱ뚜珵ᴴᏩ呄ᠾ퍘ᒥ鹨់ᩄꋔྦ瑉浥巠皱㙲皦抐皱巠皱੨皦柘皱ￜ皥ب巠皱㙲皦忈皱੨皦柘皱즠Ʋǜ勁皦즠ƲبǜV /펔B䌁皦 ᮔDž'鱤džၜ먢䇨珵呈ᠾ뤂ᐱ⿇⬿먲僧ᐱ㥲ᐲ�僬㣢ᐲᠾ랖僧Ѳ識�僬㣢ᐲ臆S㥲ᐲᬄğ

    Customers frequently viewed

    New In stock for sale, IWAYA DENKI Water Pump 25CJT0752

    IWAYA DENKI Water Pump 25CJT0752
    US$2307.69
    New In stock for sale, Panasonic Servo Motor MHMF022L1V2M

    Panasonic Servo Motor MHMF022L1V2M
    US$653.85
    New In stock for sale, Honeywell Solenoid Valve VE4025B1045

    Honeywell Solenoid Valve VE4025B1045
    US$334.62
    New In stock for sale, ROTEN Mechanical Seal 8E5K-22-X

    ROTEN Mechanical Seal 8E5K-22-X
    US$384.62
    New In stock for sale, Bristol Compressor H23B243DBEA

    Bristol Compressor H23B243DBEA
    Contact Us
    New In stock for sale, TIMKEN Bearing 67390/67322DC

    TIMKEN Bearing 67390/67322DC
    US$646.15
    New In stock for sale, Yaskawa Servo Motor SGME-04VF12

    Yaskawa Servo Motor SGME-04VF12
    US$632.50
    New In stock for sale, Copeland Compressor 4DK1-1500-TSK

    Copeland Compressor 4DK1-1500-TSK
    Contact Us
    New In stock for sale, JOHNSON Electric Motor 1030677

    JOHNSON Electric Motor 1030677
    US$3.23
    New In stock for sale, Parker Solenoid Valve 4965933D

    Parker Solenoid Valve 4965933D
    Contact Us
    New In stock for sale, Sumitomo Gear Pump QT32-10F-A

    Sumitomo Gear Pump QT32-10F-A
    US$846.15
    New In stock for sale, CKD Solenoid Valve APK11-8A-C4A-AC110V

    CKD Solenoid Valve APK11-8A-C4A-AC110V
    Contact Us
    New In stock for sale, YUKEN Vane Pump HPV3MY-20-F-LAA-K1-10

    YUKEN Vane Pump HPV3MY-20-F-LAA-K1-10
    Contact Us
    New In stock for sale, Ding Zing Oil Seal UN30*38*6

    Ding Zing Oil Seal UN30*38*6
    US$1.54

    • Welcome to O&Kmarts

      Is there anything we can help?

      Email us
    © eCommerce. 2017-2025. All Rights Reserved
    Press and drag the mouse to start taking a screenshot