How to Choose the Right Motor for Power Tools?

Motors are very common in life. I believe everyone knows them well. However, some professional knowledge may not be known to everyone. Today, I will introduce the model of the motor, the principle of the motor, the maintenance of the motor and the motor. The maintenance, to help everyone better understand it. I believe that the more you understand this machine, the more efficient it will be.

FIXMAN have a big range of product line, that the power tools are surely involved in our product range. FIXMAN power tools seperate in electric power tools and battery power tools. There are different kinds of power tools that we provide, including power drill, impact drill, impact wrench, angle grinder, rotary hammer, circula saw, angle polisher, electrical planner, marble cutter, mitra saw, etc…

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Introduction to Motor

Electric machinery (English: Electric machinery, commonly known as “motor”) refers to an electromagnetic device that converts or transmits electrical energy according to the law of electromagnetic induction. It is represented by the letter M in the circuit (D in the old standard). Its main function is to generate driving torque as a power source for electrical appliances or various machinery. The generator is represented by the letter G in the circuit. Its main function is to convert electrical energy into mechanical energy.

 

motor model

It is composed of four subsections: motor type code, motor characteristic code, design number and excitation mode code. 1. Type code is the Chinese Pinyin alphabet used to characterize various types of motors. For example: asynchronous motor Y synchronous motor T 2. The characteristic code is to characterize the performance, structure or purpose of the motor, and it is also expressed in Chinese pinyin letters. For example: B for flameproof type, YB for axial flow fan, YT 3. Design serial number refers to the sequence of motor product design, expressed in Arabic numerals. For the products designed for the first time, the design serial number is not marked, and the products derived from the series of products are marked in the order of design. For example: Y2 YB2 4. Code of excitation mode, respectively expressed by letters, S means third harmonic, J means thyristor, X means phase compound excitation. Such as: Y2– 160 M1-8. Y: Model, which means asynchronous motor; 2: Design serial number, “2″ means the product designed based on the first improvement; 160: Center height, which is the height from the shaft center to the plane of the base; M1: Base length specification, M It is a medium-sized type, where the footnote “2″ is the second specification of the M-type core, and the “2″ type is longer than the “1″ type core. 8: Number of poles, “8″ refers to an 8-pole motor.

 

Motor principle

It is made by using the phenomenon that the energized coil rotates in the magnetic field and is distributed in various users. The motors are divided into DC motors and AC motors according to different power sources. Most of the motors in the power system are AC motors, which can be synchronous motors. Or an asynchronous motor (the motor stator magnetic field speed and the rotor rotation speed do not maintain synchronous speed). The motor is mainly composed of a stator and a rotor. The direction of the force movement of the energized wire in the magnetic field is related to the direction of the current and the direction of the magnetic line of induction (the direction of the magnetic field). The working principle of the motor is the action of the magnetic field on the force of the current to make the motor rotate.

 

Motor classification

1. Brushless DC motor Brushless DC motor (BLDCM) is developed on the basis of brushed DC motor, but its driving current is uncompromising AC; brushless DC motor can be divided into brushless speed Motors and brushless torque motors. Generally, there are two types of drive currents for brushless motors, one is a trapezoidal wave (usually a “square wave”), and the other is a sine wave. Sometimes the former is called a DC brushless motor, and the latter is called an AC servo motor. To be precise, it is a kind of AC servo motor. In order to reduce the moment of inertia, the brushless DC motor usually adopts a “slender” structure. Brushless DC motors are much smaller in weight and volume than brushed DC motors, and the corresponding moment of inertia can be reduced by about 40%-50%. Due to the processing problems of permanent magnet materials, the general capacity of brushless DC motors is below 100kW.

 

Motor purchase

1. Check the appearance: the paint layer on the surface of the motor should be smooth and flat, the nameplate should be installed correctly, and the signs should be complete; the heat dissipation ribs of the closed motor base should be intact and complete with accessories; 2. Manual rotation: rotating the electric shaft by hand, the rotation should be very flexible and inertial The momentum is good, and there is basically no movement in the axial direction; 3. Diagnosis and hearing bearing: The bearing should be stable and brisk, without stagnation after 15-25 minutes of power-on operation. The sound is uniform and harmonious; the bearing temperature is not high, and there is no oil leakage or oil sling; after the operation stops, touch the motor base and end cover with your hands and feel no heat; 4. Check the wiring: open the junction box to see if the signs of the phase wires are clear and complete , Whether the contact piece is compacted and tight, and whether the nut is complete;

 

Motor maintenance

Correct maintenance of the motor can extend the service life of the motor. The motor maintenance process: cleaning the stator and rotor-replacing the carbon brush or other parts-vacuum F-level pressure dipping-drying-balancing. 1. The operating environment should always be kept dry, the surface of the motor should be kept clean, and the air inlet should not be obstructed by dust, fibers, etc. 2. When the thermal protection of the motor continues to operate, it should be ascertained whether the fault comes from the motor or the overload or the setting value of the protection device is too low. After the fault is eliminated, it can be put into operation. 3. Ensure that the motor is well lubricated during operation. The general motor runs for about 5000 hours, that is, the grease should be added or replaced. When the bearing is overheated or the lubrication is deteriorated during operation, the hydraulic pressure should be replaced in time. When replacing the grease, remove the old lubricating oil, and clean the oil grooves of the bearing and bearing cap with gasoline, and then fill 1/2 of the cavity between the inner and outer rings of the bearing with ZL-3 lithium-based grease (for 2 poles) And 2/3 (for 4, 6, and 8 poles).

 

Motor repair

How to repair the abnormal heating of the motor? Answer: The maintenance method is generally to replace the motor or perform maintenance. When the no-load current of the motor is greater than the limit data of the reference table, it indicates that the motor has malfunctioned. What are the reasons? How to repair? Answer: The internal mechanical friction of the motor is large; the coil is locally short-circuited; the magnetic steel is demagnetized; the inverter of the DC motor has carbon deposits. The maintenance method is generally to replace the motor, or replace the carbon brush, and clean up the carbon deposits.


Post time: Oct-21-2021