0.5 hp two way motor connection gear motor price in india
Maintenance method
Motor maintenance process of professional motor maintenance and repair center: cleaning stator and rotor - replacing carbon brushes or other parts - vacuum class F pressure impregnation - drying - dynamic balance calibration.
1. The operating environment should always be kept dry, the motor surface should be kept clean, and the air inlet should not be obstructed by dust, fiber, etc.
2. When the thermal protection of the motor acts continuously, it is necessary to find out whether the fault is from the motor or overload or the setting value of the protection device is too low. The motor can be put into operation only after the fault is eliminated.
3. The motor shall be well lubricated during operation. Generally, when the motor runs for about 5000 hours, the lubricating grease should be supplemented or replaced. When the bearing is overheated or the lubrication is deteriorated during operation, the hydraulic pressure should replace the lubricating grease in time. When replacing the lubricating grease, remove the old lubricating oil and clean the oil groove of the bearing and bearing cover with gasoline, and then fill 1/2 (for 2 poles) and 2/3 (for 4, 6 and 8 poles) of the cavity between the inner and outer rings of the bearing with zl-3 lithium grease.
4. When the service life of the bearing ends, the vibration and noise of the motor will increase obviously. When the radial clearance of the bearing reaches the following values, the bearing shall be replaced.
5. When disassembling the motor, take out the rotor from the shaft extension end or non extension end. If it is not necessary to remove the fan, it is more convenient to take out the rotor from the non shaft extension end. When taking out the rotor from the stator, it shall be prevented from damaging the stator winding or insulation.
6. When replacing the winding, the form, size, number of turns, wire gauge, etc. of the original winding must be recorded. When these data are lost, they should be obtained from the manufacturer. Changing the original design winding at will often worsens one or more performances of the motor, or even makes it impossible to use.
Protector
The function of motor protector is to provide comprehensive protection for the motor and give an alarm or protection in case of overload, phase loss, locked rotor, short circuit, overvoltage, undervoltage, electric leakage, three-phase imbalance, overheating, bearing wear and eccentric stator and rotor.
General knowledge of motor protection
0.5 hp two way motor connection gear motor price in india
1. Today's motors are easier to burn than in the past: due to the continuous development of insulation technology,
In the design of the motor, it is required to increase the output and reduce the volume, so that the thermal capacity of the new motor becomes smaller and smaller, and the overload capacity becomes weaker and weaker; Moreover, due to the improvement of production automation, the motor is required to run in a variety of ways such as frequent starting, braking, forward and reverse rotation and variable load, which puts forward higher requirements for the motor protection device. In addition, the motor has a wider range of applications, often working in extremely harsh environments, such as humid, high temperature, dusty, corrosive and other occasions. All of these have caused the motor to be more easily damaged than in the past, especially the overload, short circuit, phase loss, bore sweeping and other faults with the highest frequency.
2. The protection effect of the traditional protection device is not ideal: the traditional motor protection device is mainly thermal relay, but the thermal relay has low sensitivity, large error, poor stability and unreliable protection. In fact, although many equipment are equipped with thermal relays, the phenomenon of motor damage affecting normal production is still common.
3. Development status of motor protection: at present, the motor protector has developed from mechanical type to electronic and intelligent type. It can directly display the current, voltage, temperature and other parameters of the motor. It has high sensitivity, high reliability, multiple functions and convenient debugging. After the protection action, the fault types are clear, which not only reduces the damage of the motor, but also greatly facilitates the fault judgment, It is beneficial to the troubleshooting of the production site and shorten the production recovery time. In addition, the air gap magnetic field of the motor is used to detect the eccentricity of the motor, which makes it possible to monitor the wear status of the motor on-line. The curve shows the change trend of the eccentricity of the motor, so that the bearing wear, inner circle and outer circle faults can be found and handled early, so as to avoid the occurrence of bore sweeping accidents.
3. selection principle of protector: reasonably select the motor protection device, which can not only give full play to the overload capacity of the motor, but also avoid damage, so as to improve the reliability of the electric drive system and the continuity of production. The specific function selection shall comprehensively consider such factors as the value of the motor itself, load type, service environment, the importance of the main equipment of the motor, and whether the motor out of operation has a serious impact on the production system, so as to strive to be economical and reasonable.
4. Ideal motor protector: the ideal motor protector is neither the most functional nor the most advanced, but should meet the actual needs of the site, achieve the unity of economy and reliability, and have a high performance price ratio. The type and function of the protector shall be reasonably selected according to the actual situation of the site. At the same time, the protector shall be easy to install, adjust and use. More importantly, it is necessary to select a high-quality protector.
0.5 hp two way motor connection gear motor price in india
Selection of protector
Basic principle of model selection:
At present, there is no unified standard for motor protection products in the market, and there are various models and specifications. In order to meet the different use needs of users, manufacturers have derived many series of products with a wide variety, which brings a lot of inconvenience to the selection of users; When selecting the type, the user shall fully consider the actual needs of motor protection, and reasonably select the protection function and protection mode, so as to achieve good protection effect, improve equipment operation reliability, reduce unplanned shutdown and reduce accident losses.
The method of model selection:
1. Conditions related to model selection
1) Motor parameters: it is necessary to know the specification and model, functional characteristics, protection type, rated voltage, rated current, rated power, power frequency, insulation grade, etc. of the motor. These contents can basically provide a reference for users to correctly select the protector.
2) Environmental conditions: mainly refer to normal temperature, high temperature, high cold, corrosion, vibration, wind and sand, altitude, electromagnetic pollution, etc.
3) Purpose of motor: it mainly refers to the required characteristics of driving mechanical equipment, such as mechanical characteristics of different loads such as fans, water pumps, air compressors, lathes, oil field pumping units, etc.
4) Control mode: the control modes include manual, automatic, local control, remote control, independent operation of single machine, centralized control of production line, etc. The starting modes include direct, step-down, star angle, frequency sensitive rheostat, frequency converter, soft start, etc.
5) Other aspects: monitoring and management of on-site production by users, severity of abnormal shutdown on production, etc.
There are many factors related to the selection of protectors, such as installation location, power supply, distribution system, etc; It is also necessary to consider whether to configure protection for newly purchased motor, upgrade motor protection, or improve accident motor protection; It is also necessary to consider the difficulty of changing the motor protection mode and the impact on production; The selection and adjustment of protector shall be comprehensively considered according to the actual working conditions on site.
2. Common types of motor protectors
1) Thermal relay: Ordinary small capacity AC motor, with good working conditions, and there is no occasion under severe working conditions such as frequent startup; Due to poor accuracy, reliability cannot be guaranteed, so it is not recommended.
2) Electronic type: detect the three-phase current value, set the current value by potentiometer or code pulling switch, and generally adopt analog circuit with inverse time limit or definite time limit working characteristics. The protection functions include overload, phase loss, locked rotor, etc. the fault type is displayed by indicator light, and the operating power is displayed by digital tube.
3) Intelligent type: detect the three-phase current value. The protector uses a single-chip microcomputer to realize the intelligent comprehensive protection of the motor, integrating protection, measurement, communication and display. The setting current adopts digital setting and is operated through the buttons on the operation panel. The user can modify the setting of various parameters on site according to the specific conditions of the motor; Digital tube is used as the display window, or large screen LCD is used, which can support a variety of communication protocols, such as modbus, PROFIBUS, etc. the price is relatively high, and it is used in more important occasions; At present, intelligent protection devices are used for high-voltage motor protection.
0.5 hp two way motor connection gear motor price in india
4) Thermal protection type: thermal elements are embedded in the motor to protect it according to the temperature of the motor winding, and the protection effect is good; However, when the motor capacity is large, it should be used together with the current monitoring type to avoid the motor winding damage due to the hysteresis of the temperature measuring element when the temperature rises sharply when the motor is locked.
5) Magnetic field temperature detection type: the magnetic field detection coil and temperature measuring element are embedded in the motor to protect it according to the change of rotating magnetic field and temperature inside the motor. The main functions include overload, locked rotor, phase loss, overheating protection and wear monitoring. The protection function is perfect. The disadvantage is that the magnetic field detection coil and temperature sensor need to be installed inside the motor.
3. Selection of protector type
1) For stand-alone motor with low requirements for working conditions, simple operation control and little impact on production by shutdown, ordinary protector can be selected. Because of its simple structure, it is easy to install and replace on site, simple operation and high cost performance.
2) For motors with poor working conditions and high reliability requirements, especially those involved in automatic production lines, medium and high-grade intelligent protectors with complete functions shall be selected.
3) For explosion-proof motors, eccentric bearing wear may lead to high temperature at the explosion-proof gap, resulting in explosion hazards. Therefore, the wear status monitoring function should be selected. For special equipment such as high-pressure submersible pumps with large capacity, due to the difficulty in inspection and maintenance, the wear condition monitoring function should also be selected, and the bearing temperature should be monitored to avoid significant economic losses caused by chamber sweeping accidents.
4) For protectors used in places with explosion-proof requirements, corresponding explosion-proof protectors shall be selected according to the specific requirements of the application site to avoid safety accidents.
Common faults
In household electrical equipment, such as electric fans, refrigerators, washing machines, range hoods, vacuum cleaners, etc., the working power is single-phase AC motors. This kind of motor has a simple structure, so some common faults can be repaired under amateur conditions.
1. Motor does not start after power on
In addition to poor power circuit and motor winding, most of the faults are abnormal starting circuit of the motor. Electric fans, exhaust fans, washing machines and other motors are generally started and operated by capacitors; The motors of refrigerators, freezers, etc. are mostly started by resistance phase separation. Once the capacitor or phase separation resistance in the starting circuit is damaged, the motor cannot operate normally. During maintenance, the motor fault should be checked after the starting circuit fault is eliminated.
If the starting circuit is normal, it may be a local short circuit or open circuit in the internal winding of the motor. Use the multimeter R × 1. Judge by measuring the resistance value of each winding.
For example, for the refrigerator compressor motor, under normal conditions, the resistance value of the starting winding is about 23 Ω, the resistance value of the operating winding is about 10 Ω, and the normal resistance value of the starting and operating series winding should be the sum of the two.
0.5 hp two way motor connection gear motor price in india
2. Motor speed is slow and weak
When the speed of the motor is slow and powerless after power on, most capacitor starting motors have insufficient capacitor capacity, serious leakage or low power supply voltage; In addition, if the aluminum bar of the squirrel cage rotor has serious defects and broken bars, especially the washing machine motor is often started and operates alternately, the large induced current of the rotor aluminum bar is easy to break the rotor aluminum bar, which also leads to slow and weak operation.
When cracks are found in the aluminum strip, an electric hand drill can be used to drill a small hole between the cracks, insert the corresponding aluminum wire strip into the hole, then knock it flat and rivet it, and finally polish it smooth with a steel file and sandpaper. If the fracture surface of aluminum strip is large, aluminum wire gas welding can be used to repair if conditions permit.
3. Motor housing is live
Generally, the motor leakage current shall not be greater than 0.8ma to ensure personal safety.
The main reasons for the leakage of the motor shell are that the insulation of an outgoing line in the motor is damaged and touches the shell; Local burning of motor winding causes leakage between stator and housing. It is common to see that the long-term high humidity environment leads to the reduction of the insulation of the motor due to moisture and the electrification of the housing. At this time, the megger can be used to measure the insulation resistance between each winding of the motor and the casing. If it is below 2m Ω, it indicates that the motor has been seriously affected by moisture, and the stator winding of the motor should be baked to remove moisture.
