The Welding Of The Motor Windings Directly Determines The Life Of The Motor

The welding of the motor windings directly determines the life of the motor

 

Motor winding welding is the key production process of the motor production process, such as the welding of the winding main wire and the main wire, the welding of the main wire and the lead, the welding of the copper rotor guide strip and the end ring, etc., all of which will be directly related to the operating reliability and quality level of the motor. Motors of different types or sizes involve welding processes with their own particularities and are often not simply equated. Today, Ms. Shen will talk to everyone about common winding welding methods.

Welding methods can be divided into two main categories: fusion welding and brazing. Fusion welding directly melts the two workpieces together, and the metal at the joint must be heated to a molten state to complete the welding. Brazing adopts a metal material with a lower melting point than the base metal as the filler, heats the weldment and the solder metal to a temperature higher than the melting point of the solder metal and lower than the melting temperature of the base metal, and uses liquid solder metal to wet the base metal, fill the joint gap and diffuse with the base metal to achieve connection welding. Most of the welding of motor windings adopts brazing, although there is also fusion welding, but in most cases it is necessary to assist hard brazing to make up for fusion welding defects.

 

                             Common welding methods for motor windings

 

Silver brazing (gas welding)

 

This welding method is suitable for occasions with large working current, high temperature and high reliability requirements, and is also the welding method adopted by most motor manufacturers. The welding equipment is acetylene oxygen welding gun. When welding, in order to prevent scalding of the motor wire near the wire insulation, the line head should be wrapped with an asbestos rope dipped in water. At the same time, it is necessary to prevent solder and flux from flowing into the gap of the coil, scalding the insulation and causing a short circuit.

Soldering

 

Soldering is easy to operate and the soldering point is firm, so it is the most commonly used, but the working temperature is low. Commonly used soldering is soldering iron soldering and pouring tin. When the number of welding wire ends is large, the method of pouring tin can be used. Due to the limitation of the low melting point of solder tin, it is only used in small motors and motor windings with low temperature rise.

 

arc welding

 

When the conductor of the winding is thin, arc welding can be used for welding. The characteristics of arc welding are that there is no need for flux, which is fast and convenient, but when there are many parallel connections and more wire heads, if the operation is not proficient, it is easy to miss welding or weld firmly.

Copper-aluminum oxygen welding

 

When welding, the copper wire or the connecting part of the copper lead wire is first tin attached, and then the scraped aluminum wire is twisted on the copper wire, and the aluminum wire is slightly higher than the copper wire. Then apply a layer of aluminum welding powder, melt the aluminum wire with a neutral flame of gas welding, so that the aluminum is fused at the top of the copper to form a spherical solder joint. This method is used in the welding link of the main wire and the lead wire in many motor factories.

TIG welding

 

Argon arc welding is based on the principle of ordinary arc welding, the use of argon gas on the protection of metal welding consumables, through high current to melt the welding consumables on the welded substrate into a liquid state to form a molten pool, so that the welded metal and welding consumables to achieve metallurgical combination of a welding technology, due to the high temperature melt welding constantly send argon, so that the welding consumables can not contact with oxygen in the air, thereby preventing the oxidation of the welding consumables. This welding plays a good role in the welding quality of multi-turn windings.

High frequency induction brazing

 

Induction brazing is to weld the metal workpiece (generally copper) placed in the induction coil, through high-frequency alternating current, generate induction electromagnetic field, coupling on the surface of the workpiece to generate induced electromotive force, on the metal surface to form induction eddy current, relying on the metal surface generated eddy current heating, in the welding part will generally be coated with welding powder, until the workpiece reaches the solder melting temperature when welding can be, induction brazing is currently the world's cleanest and environmentally friendly heating welding method. This type of welding in the copper bar rotor application more, because the welding at the same time on several welding joints at the same time operation, the consistency of process parameters is better, but also effective solder joint deformation, no matter from the ergonomics, reliability and aesthetics and other aspects is a better process, but because the equipment cost is relatively high, the corresponding induction coil cost is also particularly expensive, so not every manufacturer adopts this welding technology.

Medium frequency induction brazing

 

Medium frequency induction brazing equipment is to assemble the surface cleaned workpieces together in a lap type, and place the filler near the joint gap or between the joint gaps.

Medium frequency induction brazing equipment can replace oxyacetylene heating, coal oven heating, box electric furnace heating and other backward heating methods for brazing and quenching heat treatment. It can greatly improve product quality, effectively save electric energy, and improve working conditions. When the workpiece and the filler metal are heated to a temperature slightly higher than the melting point temperature of the filler metal, the filler metal melts (the workpiece is not melted), and between the capillary action being sucked in and filled with the solid workpiece, the liquid filler metal and the workpiece metal diffuse and dissolve each other, and the brazing joint is formed after cold suspicion. Features of medium frequency induction brazing equipment:

1 Because the principle of medium frequency induction heating is electromagnetic induction, its heat is generated by the workpiece itself, the heating method has a fast heating rate, very little oxidation, high heating efficiency, good process repeatability, only a very slight decolorization of the metal surface, slight polishing can restore the surface to mirror brightness, so as to effectively obtain constant and consistent material properties.

Uniform heating, high temperature control accuracy, uniform heating, to ensure that the temperature difference of the heating core table is small. The temperature control system allows precise temperature control to ensure product repeatability.

The welding of the bare copper rotor guide strip of medium frequency induction brazing ground is more widely used, and the welding method has more stringent requirements for the cutting, forming and related shape of the head cover, otherwise the welding effect will be greatly reduced.

 

Based on the above information content, each motor manufacturer should combine their own equipment characteristics and product characteristics for comprehensive evaluation, but welding quality reliability is the key technology of manufacturing.