Motor bad repair method a motor repair skills? Look
Observe the motor operation process with or without abnormalities, which is mainly manifested in the following situations.
1. When the stator winding is short-circuited, you may see smoke from the motor.
2. motor serious overload or lack of phase operation, the speed will become slower and heavier "humming" sound.
3. When the motor is running normally but suddenly stops, sparks are seen coming out of loose wires; fuses are blown or parts are jammed.
4. If the motor vibrates violently, it may be that the transmission device is stuck or the motor is poorly fixed, loose foot bolts and so on.
5. If there is discoloration, burn marks and smoke stains on the contact points and connections in the motor, it means that there may be local overheating, poor contact with the conductor connections or burnt windings.
Two, motor maintenance skills? Listen
Normal operation of the motor should be issued uniform and light "humming" sound, no noise and special sound. If too much noise, including electromagnetic noise, bearing noise, ventilation noise, mechanical friction, etc., may be a precursor to failure or failure phenomenon.
1, for electromagnetic noise, if the motor emits high and low and heavy sound, the causes may be the following.
(1) the stator and rotor air gap is not uniform, the sound is high and low and high and low sound interval time, this is the bearing wear and tear so that the stator and rotor is not centrifugal.
(2) three-phase current imbalance. This is the existence of three-phase winding mis-grounding, short circuit or poor contact and other reasons, if the sound is very dull, it means that the motor is seriously overloaded or lack of phase operation.
(3) loose iron core. Motor in operation due to vibration and make the iron core fixing bolts loose cause iron core silicon steel sheet loose, issued noise.
2, for bearing noise, should be in the motor running often listening.
Listening method is: one end of the screwdriver against the bearing mounting parts, the other end close to the ear, you can hear the bearing running sound. If the bearing is running normally, the sound is continuous and small "rustle" sound, there will not be high and low changes and metal friction sound. If the following kinds of sound is not normal.
(1) bearing running "squeak" sound, this is the metal friction sound, generally for the bearing oil shortage caused by the bearings should be disassembled to fill the appropriate amount of grease.
(2)If there is "chirping" sound, this is the sound of the ball rotation, generally for the grease dry or oil caused by the lack of grease, you can add the appropriate amount of grease.
(3) if there is a "click" sound or "crunch" sound, it is the irregular movement of the ball bearings and the sound, this is the bearing ball damage or motor for a long time, the grease is dry.
3. If the transmission mechanism and the driven mechanism to send a continuous and not high and low sound, can be divided into the following cases.
(1) periodic "popping" sound, caused by the belt joint is not smooth.
(2) periodic "thud" sound, for the coupling or pulley and shaft loosening as well as key or keyway wear caused.
(3)Uneven collision sound, caused by the wind blade collision fan cover.
Three, motor repair skills? Smell
By smelling the motor odor can also determine and prevent failure. If you find a special smell of paint, the motor internal temperature is too high; if you find a very heavy paste or burnt smell, it may be the insulation is broken or the winding has burned.
Four, motor repair skills? Touch
Touch the temperature of some parts of the motor can also determine the cause of failure. To ensure safety, the back of the hand should be used to touch the motor shell, bearing around the part, if the temperature is found to be abnormal, the cause may be the following.
1. Poor ventilation. Such as fan off, ventilation duct blockage.
2. Overload. Resulting in excessive current and overheating of the stator winding.
3. Stator winding turn-to-turn short circuit or three-phase current imbalance.
4. Frequent starting or braking.
5. If the temperature around the bearings is too high, it may be due to bearing damage or lack of oil.
The classification of the motor 1. stepper motor
Mainly used in the field of CNC machine tool manufacturing, because the stepper motor does not need A/D conversion, can directly convert the digital pulse signal into an angular displacement, so it has been regarded as the most ideal CNC machine tool actuating elements.
2. Brushless motor
Mechanical characteristics and regulation of the characteristics of the linearity of good, wide range of speed, long life, easy maintenance and low noise, there is no brush due to a series of problems caused by the motor, so this motor in the control system has a great deal of applications.
3. DC motor
has the advantages of good speed performance, easy to start, able to carry heavy starting, so the current DC motor is still widely used, especially after the emergence of silicon controlled DC power supply.
4. Asynchronous motor
has the advantages of simple structure, manufacturing, easy to use and maintenance, reliable operation and smaller quality, lower cost. Asynchronous motor is widely used to drive machine tools, pumps, blowers, compressors, lifting and winching equipment, mining machinery, light industrial machinery, agricultural and sideline product processing machinery and most of the industrial and agricultural production machinery, as well as household appliances and medical equipment.
5. Synchronous motor
Mainly used for large-scale machinery, such as blowers, pumps, ball mills, compressors, rolling mills and small, micro-instrumentation or as a control element. Three-phase synchronous motor is the main body. In addition, it can also be used as a regulator to deliver inductive or capacitive reactive power to the grid.
The working principle of dc motor dc motor octagonal full laminated structure, not only high space utilization, but also when the static rectifier power supply, can withstand pulsating current and rapid changes in load current. DC motors are generally not with series excitation winding, applicable to the need for forward and reverse rotation in automatic control technology. According to the user's needs can also be made with series-excited winding.
The coil is connected to the commutator, the commutator is fixed on the rotating shaft, rotating with the motor shaft, between the commutator and the commutator and the rotating shaft are insulated from each other, they form a whole is called commutator. Brushes A and B are fixed in space.
In the motor of the two brush end plus DC voltage, due to the brushes and the role of the commutator will be introduced into the armature coil, and to ensure that the same pole coil side of the current is always a direction, and then ensure that the pole coil side of the direction of the electromagnetic force remains unchanged, to ensure that the motor can be rotated continuously, when the conductor in the magnetic field cutting the magnetic lines of force in the conductor generates an induced current, the joint induction current and the magnetic field. When the conductor cuts the magnetic field, the induced current is generated in the conductor, and the combined effect of the induced current and the magnetic field exerts a driving force on the motor rotor to realize the conversion of electrical energy into mechanical energy to drag the production machinery, which is the working principle of the DC motor. Note that the direction of the current in each coil side is alternating.
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